The Design of a Portable Pipe Threading Machine Citation Wallace, Richard Alfred (1949) The Design of a Portable Pipe Threading Machine. Engineer's thesis, California Institute of Technology. doi:10.7907/zhdz-cx45. https://resolver.caltech.edu/CaltechTHESIS:09052025-021606031 Abstract This thesis is the presentation of the design of a portable pipe threading machine having improved operational usefulness and increased sales advantage over present machines. An investigation of the present portable pipe threading machine market has been conducted including a product study, a survey of consumer preference in a sample market, an analysis of the present market, and a patent investigation. Technical research has been done consisting of tests to determine operating torque loads, an investigation of chaser form and threading speed, development of automatic chucking systems, and an investigation of suitable materials and new processes for portable pipe threading machine manufacture. Design studies have been made of an ideal portable pipe threading machine, of portable rotary-tool machines, and of portable rotary-pipe machines. The final design offers the following improved features over present portable machines: (1) separate threading assemblies for each pipe size, but only one opening mechanism; (2) a power-driven cut -off mechanism; (3) a reamer mounted behind the diehead; (4) a positive gripping automatic chucking system. A stress analysis, a cost analysis, a weight analysis, a market estimate, sales and advertisement features, maintenance and service considerations, and assembly drawings have been prepared for this machine. Item Type: Thesis (Engineer's thesis) Subject Keywords: (Industrial Design) Degree Grantor: California Institute of Technology Division: Engineering and Applied Science Major Option: Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1949 Record Number: CaltechTHESIS:09052025-021606031 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:09052025-021606031 DOI: 10.7907/zhdz-cx45 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 17667 Collection: CaltechTHESIS Deposited By: Ben Maggio Deposited On: 12 Sep 2025 09:58 Last Modified: 12 Sep 2025 10:02 Thesis Files PDF - Final Version See Usage Policy. 42MB Repository Staff Only: item control page

THE DESIGN OF A PORTABLE PIPE THREADING MACHINE Thesis by Richard A. Wallace In Partial Fulfillment of the Requirements For The Professional Degree of INDUSTRIAL DESIGNER California Institute of Technology Pasadena, California 1V49 ACKNOWLEDGMENTS The designer wishes to thank the members of his thesis reviewin g committee: Mr. J. P. Youtz, Dr. D. S. Clark, and Mr. B. Morant, for the valuable suggestions and assistance which they offered. To the faculty and the class members of the Industrial Design Section, the designer is most appreciative for the creative stimulus which their frank and honest criticism provided. Many manufacturers, salesmen, and consumers of pipe threading machinery have graciously given of their time and effort, and the designer sincerely thanks each of them. ABSTRACT This thesis is the presentation of the desi gn of a portable pipe t h readin g machine having improved operational usefulness and increased sales advanta ge over present machines. An investi gation of the present portable pipe threadin g machine market has been conducted includin g a product study, a survey of consumer preference in a sample mark et, an analysis of the present market, and a patent investigation. Technical research has been done consistin g of tests to determine operating torque loads, an investi gation of chaser form and threadin g speed, development of automatic chuckin g systems, and an investigation of suitable materials and new processes for portable pipe threading machine manufacture. Design studies have been made of an ideal portable pipe threadin g machine, of portable rotary-tool machines, and of portable rotary-pipe machines. The final design offers the followin g i mproved features over present portable machines: (1) separate threading assemblies for each pipe size, but only one opening mechanism; (2) a power-driven cut -off mechanism; (3) a reamer mounted behind the diehead; (4) a positive grippin g automatic chucking system. A stress analysis, a cost analysis, a weight analysis, a market estimate, sales and advertisement features, maintenance and service considerations, and assembly drawin gs have been prepared for this machine. TABLE OF OONTENTS Title APPENDICES A. Rotamatic Appearance Design Considerations 57 Rotamatic Drawing Number Schedule 61 c. Rotamatic Stress and Load Analysis 63 D. Rotamatic Weight Analysis 72 Rotamatic Cost Estimate 75 Rotamatic Market Estimate 80 Rotamatic Sales and Advertising Features 82 Rotamatic Maintenance and Service Requirements 85 Specifications of Present-Day Portable Pipe Threading Machines 86 Pipe Threading Machine Patents 87 Su ggestions for Future Portable Pipe Threading Machine Design 88 Bibliography 90 B. E. F. G. H. I. J. K. L. 'l'ABLE OF OONTENTS Title APPENDICES A. B. c. D. E. F. G. H. I. J. K. L. Rotamatic Appearance Design Considerations 57 Rotamatic Drawin g Number Schedule 61 Rotamatic Stress and Load Analysis 63 Rotamatic Weight Analysis 72 Rotamatic Cost Estimate 75 Rotamatic Market Estimate 80 Rotamatic Sales and Advertising Features 82 Rotamatic Maintenance and Service Requirements 85 Specifications of Present-Day Portable Pipe Threading Machines 86 Pipe Threadin g Machine Patents 87 Su ggestions for Future Portable Pipe Threadin g Machine Design 88 Bibliography 90 ILLUSTRATIONS AND FIGURES Title After Page 1 Rotamatic Pipe Threading Machine 3 2 Rotamatic Operation Sequence 4 3 Threading Torque Test Set-Up 16 4 Cut-Off Torque Test Set-Up 16 5 Pipe Threading Torques 17 6 Threading Chaser With SR-4 Strain Gages Attached 17 7 Threading Chaser Forms 19 8 Hobbed Chaser F'orm For Cutting Iron & Mild Steel 19 9 Rotating-Wedge Chuck Jaw Profiles 23 10 Rotating-Wedge Chuck Jaw •reeth Shape 23 11 Self-Holding Sliding-Wedge Chuck Jaw 23 12 An Ideal Portable Pipe Threading Machine 29 13 Portable Rotary-Tool Pipe Threading Machines 31 14 Opening Diehead Designs 34 15 Reamer Designs 34 16 Cut-Off Mechanism Designs 35 17 Chuck Designs 35 18 Rotamatic--Front Views 38 19 Rotamatic--Rear Views 38 20 Rotamatic--Pictorial 38 21 Rotamatic Diehead Threading Ass.embly 39 22 Rotamatic Diehead Frame Assembly 39 23 Rotamatic Cut-Off Tumble Gear Assembly 41 24 Rotamatic Cut-Off Frame Assembly 41 ILLUSTRATIONS AND FI GURES Title After Page 25 Rotamatic Carria ge Assembly 43 26 Rotamatic Spindle and Chuck Assembly 44 27 Rotamatic Motor Assembly 46 28 Rotamatic Cutting Oil System 47 29 Rotamatic Frame Assembly 48 30 Rotamatic Final Assembly 49 31 Rotamatic Operation--Cutting Off 52 32 Rotamatic Operation--Threading 52 33 Rotamatic Operation--Reaming 53 34 Rotamatic Operation~-Making-Up 53 35 Rotamatic Half Scale Visualization Model 58 36 Beaver Model-A Pipe Threading Machine 86 37 Quijada No. 3A Pipe Threading Machine 86 38 Beaver Model-B Pipe Threading Machine 86 39 Toledo High Speed Pipe Threading Machine 86 40 Toledo No. 999 Pipe Threading Machine 86 41 Red-E-Haul Pipe Threading Machine 86 42 Oster No. 582 Pipe Threadin g Machine 86 43 Oster No. 502 Pipe 'rhreadin g Machine 86 44 Oster No. 531-A Pipe Threading Machine 86 1 FOREWORD INTRODUCTION AND SCOPE There are three general types of pipe threading machines in use today: (1) Automatic and semi-automatic production machines which will thread all sizes of pipe from 1/16 11 to 12 11 • (2) Portable field machines which will thread, ream, and cut-off pipe below 2 11 diameter by tools attached to a carriage sliding on ways. (3) Power vises which rotate pipe below 2 11 diameter and use hand tools to thread, ream, and cut-off. The Rotamatic pipe threading machine developed in this thesis is a portable field machine. Its design is the result of careful consideration of the sales, production, and operational requirements which present day portable pipe threading machines must meet. The thesis is composed of four major parts: a market investigation, technical research, design studies, and the final design description. The market investigation includes a survey of present portable pipe threading machines, a field survey of consumer preference in the Southern California area, an analysis of the extent and condition of the present pipe threading machine market, and an investigation of threading machine patents. 2 FOREWORD The technical research consists of operational tests to determine threadin g and cut-off torques, an investi gation of chaser form and threadin g speeds, research and development of two automatic chucking systems, and an investi gation of suitable materials and new processes for use in the manufacture of the Rotamatic. The design studies include a visualization of an ideal pipe threadin g machine, preliminary designs of five portable rotary-tool machines, and a desi gn analysis of the component parts of portable rotary-pipe machines. The final design of the Rotamatic pipe threading machine is based on the results and conclusions of the market investigation, the technical research, and the design studies. It consists of a detailed description of the construction and operation of the machine. The appendices include en gineerin g, market, and sales data pertainin g to the Rotamatic; a tabular summary of the specifications of present day portable pipe threadin g machines; and the desi gn er's suggestions for future pipe threadin g machine design . 3 FOREWORD FINAL DESIGN SUI'IIM.ARY The Rotamatic pipe threading machine designed in this thesis is shown in Illustration 1. Its general specifications are: size - 38.50 11 long, 14.7511 wide, 14.3511 high; weight- 220#; standard range of pipe - ½" - 2 11 ; spindle speed - 40-55 rpm, variable with load; price - $625.00 (with 6 threading assemblies.) The Rotamatic is painted a warm, light grey with black trim. The operating handle knobs are red plastic. The threading mechanism consists of separate threading assemblies for each size pipe, but of only one scroll opening mechanism operated by the handle mounted on top of the diehead. A downward motion of the handle closes the chasers and locks the threading assembly in place, while an upward motion opens the chasers and a lows the threading assembly to be removed. Provision is made in the threading assemblies for adjustment for cutting oversize and undersize threads. The cut-off mechanism is power driven by a friction drive from the pipe. nism. Operation is by the handle mounted on top the mecha- A downward motion of the handle causes the cut-off wheel to move against the pipe, while an upward motion backs the cut-off wheel away from the pipe at high speed. The cut-off mechanism will slide to align itself about any size pipe. TAMATIC I. THE ROTAMATIC PIPE THREADING MACHINE 4 FOREWORD A cone reamer is mounted on the rear of the cut-off mechanism, and is moved into position behind the diehead chasers by sliding the cut-off mechanism towards the operator. The carriage which carries the threading and cut-off mechanisms is moved by a rack and pinion gear feed by the positioning wheel mounted on the frame of the machine. The threading and cut-off mechanisms may be swung away from the carriage for making-up fittings. 'l'he chucking system driving the pipe is fully automatic. There is a front gripping chuck and a rear aligning chuck which open and close simultaneously. Operation is by the handle mounted on the front of the driving head. A down- ward motion of the handle starts the motor which closes the jaws. A further downward motion lifts the closing force. An upward motion reverses the motor and opens the jaws. Positive gripping of the front chuck jaws is insured by a master torque jaw which grips tighter as the torque load increases. The motor is a½ HP, sealed, gear-in-head, series motor, driving a spur pinion gear which meshes with the spindle gear. The motor mounts are fiber to reduce noise and vibration. The motor switch is operated by the chuck operating handle. A vane type oil pump, driven from the spindle gear, supplies CUTTING - OFF 2. ROTAMATIG REAMING THREADING OPERATION SEQUENCE MAKING -UP 5 FOREW ORD cuttin g oil to the threadin g mechanism. The oil is automati- cally shut off when the threading and cut-off mechanisms are in make-up position. Chips are caught on a removable metal tray. 'r he frame is a one-piece aluminum casting. used to support the s p indle. Ball bearin gs are The carria ge guides are g round, heat-treated steel. 'r he operation sequence of the Rotamatic cutting -off, t h readin g , reamin g , and makin g-up a piece of pipe is shown in Illustration 2. Estimate d operation times for 2 11 pipe are: Cuttin g-off, 6 sec.; Threadin g , 20 sec.; Reamin g , 4 sec.; Making-up, 15 sec. Patent ri ghts on novel features of the Rotamatic are reserved by the desi gn er. 6 MARKET INVESTIGATI ON PRODUCT SURVEY Thirty five letters were written in October 1948 to the pipe threading machine manufacturers listed in Thomas Register. The purpose of these letters was twofold: (1) to obtain manufacturers' reaction to the initial concept of the design of a portable pipe threading machine (a machine having a maximum pipe capacity of 1 11 , weighing approximately 50 pounds, costing around $300, and rotating the tools rather than the pipe); and (2) to collect sales data and engineering specifications of the present portable machines manufactured and sold by these companies. The significant information contained in the replies to these letters was as follows: (1) The capacity of the machine to meet the full need of the present market would need to be large enough to handle 2 11 pipe. (2) The weight was lower than necessary. To be so light would necessitate the use of too many high-cost, high precision parts. The machine might weigh as much as 100 pounds and still be more portable than present day machines. (3) The retail cost should be in the vicinity of $3.00 per pound if the machine is made chiefly of aluminum, or $2.00 per pound if made chiefly of ferrous materia],.s. 7 (4) MARKET INVESTIGATION The construction of the machine must be durable enough to withstand excessive abuse and prolonged overloads. The principal manufacturers of portable pipe threading machines as indicated by this survey are: (1) American Die and Tool Co., Reading, Penna. (2) Beaver Pipe Tools, Inc., Warren, Ohio (3) The Oster Manufacturing Co., Cleveland, Ohio (4) Quijada Tool Co., Inc., Los An geles 32, Cal. (5) The Toledo Pipe Threading Machine Co., Toledo, o. The portable machines manufactured by these companies are shown in Illustrations 36 to 44 inclusive. Specifications of these machines are tabulated in Appendix I. The power vises and large pipe threadin g machines manufactured by these companies and other companies were not considered as bein g of sufficient informative value for this thesis study and were not investi gated. CONSUMER FIELD SURVEY A consumer field survey was conducted during the first three months of 1949. The purpose of this survey was (1) to de- termine consumer lik es and dislikes of present pipe threadin g machines, and (2) to become acquainted with portable pipe threadin g machine operational requirements. MARKET INVESTIGATION 8 A total of 32 interviews made up the survey. Names were selected according to a predetermined sequence from the local telephone directories. The primary area was Pasadena (18 interviews), chosen because of its easy access. The Los Angeles area (9 interviews) and the Long Beach area (5 interviews) were used as checks against the Pasadena area. The interviews consisted of four major groups of consumers. Plumbers were the largest .group interviewed. This included 13 of the Pasadena interviews, 5 of the Los Angeles interviews, and 4 of the Long Beach interviews. All sizes of plumbing establishments from large heating and plumbing contractors employing approximately 100 people to one-man shops were included in this group. An effort was made to speak with men on all levels of employment. Owners, estimators, master plumbers, shop men, and apprentice plumbers were interviewed. The head plumbing instructor of the Pasadena City College, where an off-job training course in plumbing is given, was interviewed. Plumbing supply shops included 2 of the Pasadena interviews, 4 of the Los Angeles interviews, and 1 of the Long Beach interviews. These shops varied in size and volume of business from large departmental businesses to small 2 or 3-man shops. Pipe threading machine jobbers included 3 of the Los Angeles interviews. One of these jobbers was also the largest re- 0 MARKET INVESTIGATION 9 builder of pipe threadin g machinery in Southern California. Electrical contractors included 3 of the Pasadena interviews. All of these concerns employed over 50 people. The technique of the interviews varied with the different groups. With plumbers the individual was first acquainted with the nature and scope of this thesis project. pattern of questions was asked. No set The conversation was cast in such a direction as to ascertain what he liked most about his machine, what he liked least, and what he would like to see incorporated in a machine which he might buy in the future. With plumbing supply shops the purpose was to learn • the requirements which they placed upon pipe threading machines. Questions concernin g present supply channels of plumbing supplies were also asked. With pipe threading ma- chine jobbers the purpose was to determine sales features, sellin g problems, and repair problems of threading machinery. The conversations were more concerned with economic considerations than with mechanical features of the machines. With electrical contractors the technique was the same as with the plumber interviews. The questions asked were modified to fit their special interest in iron pipe for solid conduit work. The time spent on each interview varied from approximately 15 to 45 minutes. An effort was made to be as brief as possible. 10 MARKET I:N--VESTIGATION A general summary of the information obtained from the four groups of consumers interviewed is as follows: (1) Portable pipe threading machines were used by approximately half the establishments interviewed. Power vises were used in the remainder. (2) - Increased speed was desired by practically all plumbers. This interest was more pronounced in large contracting shops using several portable machines than in small shops using power vises. (3) A light-weight machine would be very desirable if it would be s~rong enough to withstand the usual abuse and overload presently incurred. (4) The price of present-day machines was considered reasonable, although any reduction would be welcome. (5) The uses of portable machines varied from being used entirely in the shop to being used entirely on the job. (6) Most machines were used in both capacities. The cut-off operation should either be speeded up on the threading machine, or be done on special machines. Several contracting shops were using car- borundum-wheel cut-off machines. Wheel and roller hand cut-off was preferred to blade cut-off for general work. (7) Separate opening dieheads for each size pipe were desired for greater speed, convenience, and 11 dependability. MARKET INVESTIGATION Any design which would lower the high initial cost of these mechanisms without sacrificing operational accuracy and efficiency would be highly desirable. , (8) Reaming by the use of burr reamers or some simi- lar device was thought desirable ( 9) to increase speed. An automatic chuck which would hold 2 11 pipe with- out slipping, and not wear out quickly would be very desirable . . (10) Bent or curved pipe handling ability by a portable pipe threading machine would be very helpful for some jobs. No significant difference in machine working requirements or in consumer preference was noted in the three areas surveyed. However, it was felt that the Southern California requirements for portable pipe threading machines are not entirely representative of the requirements of other areas of the United States. For a definite, conclusive survey of this sort, a large number of people in several areas of the country would need to be interviewed, and the results tabulated and compared. The information thus assembled was used as a basis of reference for the design of the Rotamatic pipe threading machine developed in this thesis. 12 lflARKET INVESTIGATION MARKET ANALYSIS The pipe threading machine industry is a small section of the machine tool industry. There are 37 companies listed in Thomas Register under the general heading of Pipe Threading Machinery. This list is composed of manufacturers, jobbers, and rebuilders of all types of pipe threading machinery and equipment. The size of the five companies manufacturing portable pipe threading machines can be approximated by the capital rating assigned them by Thomas Register: (1) American Die and Tool Co.--over $1,000,000 (2) Beaver Pipe Tools, Inc.--between $ 500,000 and $1,000,000 (3) The Oster Manufacturing Co.--over $1,000,000 (4) Quijada Tool Co., Inc.--between $100,000 and $300,000 (5) The Toledo Pipe Threading Machine Co.--over $1,000,000 The distribution of portable machines is direct from the factories to the jobbers. These jobbers may be machine tool retailers, plumbing supply retailers, pipe supply companies, or hardware and metal supply companies. Factory representa- tives call on these retail outlets for sales orders. bers buy through the retail outlets. Plum- There is a small auxi- iary market of rebuilt machines sold by machine shops which specialize in rebuilding machine tools. The life of portable machines varies with the make of machine 13 and the manner of use. INVESTIGATION MARKET Some makes of machines, if used carefully and periodically overhauled, will last until antiquated by design evolution. Other makes are less durable and need replacemnt of parts after several hundred hours of operation. The ave~age life as indicated by the Southern California market is approximately six years.- For individual machines the life may be as low as three years and as high •as ten. The volume of portable pipe threading machines manufactured and sold per year is not available in any government or private publication, and the manufacturers of these machines are unwilling to release any production figures. However, the annual volume may be established with reasonable accuracy in the three following ways: (1) Estimations of men associated with the industry fix the total volume manufactured per year at approximately 5000 machines. {2) The Statistical Abstract of the United States 1948 1 lists a total of 37,112 heating and plumbing establishments recorded in the census of 1939. Of these estab- lishments 4,686 have over $25,000 capital while 32,426 have under $25,000 capital. On the basis of the con- sumer survey made by the designer of Southern California, it appears safe to allow three portable machines for each of the plumbing establishments of over $25,000 MARKET INVESTIGATION 14 capital, and one portable machine for half of the establishments under $ 25,000. By this distribution there are a total of 30,000 portable machines in use in the United States. Assuming that the present market is essentially the same as the 1939 market, and that the average life of each machine is six years, there is an average annual market of 5000 machines. This figure does not re present sales of portable machines to factories and institutions for repair work. It can be assumed that this market would add as many as 500 machines per year to the market, giving a total annual volume in this case, of 5500 portable machines. (3) The Census of U. S. Manufacturers 1939 2 lists the total value of pipe threadin g machines of all types manufactured in 1937 as $1,529,383, and in 1939 as $ 1,073,489. Assuming 80 Jl of this value to be portable machines at an average cost of $300 each, and assuming the volume to be essentially constant each year, the annual volume is approximately 4500 portable machines. An annual market of approximately 5000 portable pipe threading machines may be assumed with reasonable accuracy on the basis of these calculations. No attempt has been made to determine either the volume or the value of the market of rebuilt portable machines. 15 MARKET INVESTIGATION PATENT SITUATION A search of the patent files in Washington, D. C. was made by the designer in December 1948. Appropriate classes of Divisions 10, 29, 74, and 82 were searched. The patents noted as bein g of interest in the design of a portable machine are listed in Appendix J. Manufacturers' sales literature was checked for patents issued and applied for on present portable pipe threading machines. These patents are also listed in Appendix J. Copying patented elements on the Rotamatic was avoided. An effort was made to use mechanisms upon which there are no patent restrictions and to develop mechanisms which are sufficiently different from present design to be patentable in their o~~ ri ght. 16 TECHNICAL RESEARCH THREADING AND CUT-OFF TORQUE TESTS Operational threading and cut-off torque loads were obtained by a series of tests using a Toledo 999 pipe threading machine, Rigid 11-R and 65-R hand threading dies, and a Rigid wheel and roller hand cut-off tool. This equipment is owned by the Department of Buildings and Grounds of the California Institute of Technology. The threading torque test was conducted as follows: The pipe threadin g machine was set up adjacent to a set of platform scales. The hand threading dies were used for threading instead of the machine dieheads. The lever arm of the hand threadin g dies was made to bear upon the platform scales while the thread was bein g cut by the machine. up is shown in Illustration 3. The test set- Care was taken to achieve point contact between the threading die lever arm and the platform scales support. Rigid 11-R threadin g dies were used to thread 1/2", 3/4", and 1 11 wrou ght iron pipe. A Rigid 65-R die set was used to thread 1 11 , l¼", 1½11 , and 2 11 wrought iron pipe. The depth of the 11-R chasers was l", and the thickness, 3/16 11 • The depth of the 65-R chasers was 1 11 , the thickness, 1/4". Three runs were made usin g different P\ ~7ces of each diameter pipe. All chasers were sharp and a sulphur base cuttin g oil was used durin g all runs. The cut-off torque test was conducted as follows: The Rigid 3. THREADING TORQUE TEST SET- UP. 4. CUT-OFF TORQUE TEST SET- UP. 17 TECHNICAL RESEARCH hand cut-off tool was set up to cut off pieces of black iron pipe turned by the machine as shown in Illustration 4. were read on a spring scale. Loads Care was taken to keep the spring scale at right angles to the cut-off tool handle. readings were made on each size pipe. Several No cutting oil was used. A plot of the average threading torques obtained is shown in Figure 5. It was felt that the difference in the torque to thread l" pipe with the 11-R d~set and the 65-R die set was caused by the difference in the thickness of the chasers. The average cut-off torque for wheel and roller cut-off was found to be 80"#. There was no appreciable variation in this value for the different pipe diameters tested. Pipe threading torques are not listed in any handbooks or engineering publications available to the designer., Letters sent to the five major manufacturers of portable pipe threading machines and to the Rigid Tool Company asking for this information were completely futile. Inasmuch as cutting torques, milling torques, and drilling torques are included in standard handbooks, the designer feels that companies who have this information would do the engineering and machine tool profession a needed service by making threading torque values publicly known. The tangential forces acting upon the chasers can be 1/J 0 I 60 C / z ::, 0 ll. ~ ~ 1200 l&J ::> a 0: 0 t- 80 0 I I.!) -z 0 <{ I I / ✓ / / / / / / l.&J 0: o .:c 400 t- RIGID 11-R DlES "" RIGID 65-R DJES 0 .500 1.000 PIPE OUTSIDE 1.500 2,000 2.500 DJ A METER - INCHES FIG. 5 - PIPE THREADING TORQUES. FIG. 6 - THREADING CHASER WITH SR-4 STRAIN GAGES ATTACHED. TECHNICAL RESEARCH 18 calculated from the threading torque values obtained. The radial forces however, can not be determined from these data. A test for accurately determining both the tangential force and the radial force exerted on a threading chaser may be made by gluing four standard SR-4 strain gages on each side of a chaser as shown in Figure 6. The chaser could be clamped, and calibrated under static load in both the tangential and radial directions. Threading loads could be measured by a galvanometer and bridge circuit. The total work done in cutting metal is known to be composed of the following parts: ( 1) friction work caused by the chip sliding over the tool face; (2) plastic strain energy to curl the chip; (3) work to separate the chip from the work-piece. Merchant 3 , Zlatin 4 , and Alim 5 have made determinations of work done and have developed force relationships for the orthogonal cutting of metal with a continuous chip. However, no w:>rk has yet been done using v-profile cutters or threading chasers. The further investigation of the work done to thread metal would be the subject of a separate research and is outside the scope of this thesis. C~SER FORM AND THREADING SPEED INVESTIGATION Threading chasers are made of carbon and of high-speed steel. Carbon steels for this purpose contain approximately 1.10 to 19 TECHNICAL RESEARCH 1. 30 per cent carbon w.i. th little or no alloying elements. Standard high-speed steels may be hi gh-tungsten low vanadium, low-tun gsten high-vanadium, molybdenum, or molybdenum-tun gsten steel alloys. Special hi gh-speed steels may be high-tungsten hi gh-vanadium, low-tungsten cobalt, or high-tun gsten cobalt steel alloys. 6 There are four general forms of chasers as illustrated in Figure 7: (1) Circular chasers are used on production pipe threading machines were their increased cost is offset by their increased speed and precision. (2) Tan gent chasers are used interchangeably wlth circular chasers on production machines. (3) Milled chasers, because of their tendency to chatter after a few sharpenin gs, are not generally used on portable pipe threadin g machines. (4) Hobbed chasers are the usual form used on port- able pipe threadin g machines and on hand pipe dies. rhe recommended form for sharpenin g hobbed chasers for cut- 1 ting wrought iron or SAE 1010-1035 steel is with a hook an)gle of 5o as illustrated in Figure 8. 7 This an gle may be cut by hand, but should be done on a grinding fixture for best results. The chaser may be sharpened as often as re - quired until too weak to withstand threading torques. CIRCULAR M.ILLED CHASER CHASER FIG. 7- THREADING CHASER FIG. 8 - HOBBED CHASER AND FORM MILD STEEL. FOR TANGENT CHASER HOBBED CHASER FORMS. CUTTING IRON 20 TECHNICAL RESEARCH The surface speed at which a pipe may be threaded depends upon the following variables: (1) the hardness of the pipe metal; (2) the kind of steel of which the chasers are made and their heat treatment; (3) the sharpness and the cutting face angles of the chasers; ( 4) the depth of the thread being cut; (5) the rigidity and resonant characteristics of the threading machine; (6) the cutting oil being used. Threading speeds are determined on the basis that the chasers remove the same amount of metal in a given time for all thread pitches. The recommended surface speed using carbon or high- speed chasers, for threading between 8 to 10 threads per inch, standard taper pipe threads produced by a jam cut, is 15 fpm for wrought iron and 22.5 fpm for SAE 1010-1035 steel. 7 The principal functions of a cutting oil vvhen used with threading chasers is: (1) to carry off heat developed by the separation of the chips from the pipe; (2) to lubricate the chips as they are removed from the pipe; (3) to improve the surface finish of the thread; (4) to increase the life of the chaser; (5) to flush out the threading area and wash out small chips. The lubricant recommended for threading wrought iron is soluble oil, and for threading SAE 1010-1035 steel is mineral lard (20% lard) oil. 7 In general practice petroleum or lard oil with a sulphurized base have proven very satisfactory. 21 TECHNICAL RESEARCH AUTOMATIC CHUCKI NG SYST EM DEVELOPMENT Present demands for speed in threading pipe have made practical the development of automatic chucks. As a part of the design of the automatic chuck used on the Rotamatic, research on automatic methods of chuckin g pipe was done. A chuck is basically a friction clutch in which one element is the power-driven machine and the oth er the working-piece. To hold, a chuck must exert a friction force on the surface of the working -piece which will overcome any working torque load. A wed ge action is usually used in the chuck to create this friction force. It is desirable that a chuck be self- holding by being constructed so that the working torque load will tend to increase the friction force. Such a self- holdin g feature sho u ld also be easil y and instantly releasing upon opening t h e chuck. It is desira b le that a chu ck be self-lockin g and need no further app lication of locki ng force to hold the jaws a g ainst the working-piece after the initial ti ghtening. In an automatic chuck the initial ti gh tening force comes from a source other than the operator. This force ma y be applied by the driving motor, or by a separate power mechanism. The most economical method is by the use of t h e drivin g motor and a friction drag mechanism. Unless the friction drag is removed after the workin g-piece has been gripped tightly, it 22 TECHNICAL RESEARCH will cause an additional load on the driving motor and wear to the friction drag mechanism. Two types of automatic chucks, which use the power of the driving motor to operate them, were investigated: (1) a rotating-wedge chuck, and (2) a sliding-wedge chuck. An automatic rotating-wedge chuck has three jaws (usually) attached to the spindle by rotating means. The jaws are ro- tated by planetary gears attached to them. The motor may (1) be connected to the planetary gears by an internal gear and have a spindle restrained by friction drag, or (2) be directly connected to the spindle and have an external gear enga ging the planetaries which is restrained by friction drag. The friction force which a rotating-wedge chuck can exert is dependent upon the following three major factors: (1) The pressure angle of contact between the chuck jaws and the pipe determine the profile of the rotating jaw. This profile may be generated by a tangent envel- ope similar to the way in which an involute gear tooth profile is generated. Figure 9 shows a 10°, 15°, and 20° pressure angle jaw for comparison of profile. It can be seen that as the pressure angle decreases, the jaw becomes fuller, and the an gle through which it rotates increases. A o0 jaw is a segment of an Archimedes spiral. Handbooks give 150 as a maximum wedge angle for a self- TECHNICAL RESEARCH 23 locking fit. The exact angle to be used on these jaws would need be determined by experiment. If the an gle is too small the jaw will tend to lock too ti ghtly in place and be difficult to open. If too large, the jaw will not be self-locki n g enough to overcome centrifugal force, and will not remain in place a gainst the pipe without a constant closing moment applied to it. (2) The shear strength of the pipe determines for a given jaw tooe_h penetration the torque load which will cause the pipe to slip. If the magnitude of the torque and the penetration of the jaw tooth is such that the load rises above the ultimate shear strength of the pipe, the jaw tooth will become a shaving tool and remove a cutting from the surface of the pipe. (3) The jaw teeth shape determines the self-holding characteristics of the chuck. The shape must be such that there is no unlockin g force transmitted to the jaw by the pipe as the workin g torque is applied. If the shape of the jaw teeth are as shown in Figure 10, as torque is applied, the jaw will tend to lock tighter a gainst the pipe. For this action to occur the jaw teeth must have sufficient initial contact with the pipe surface so that the stress in the pipe is kept below shear ultimate. The main advanta ge of a rota tin g-wed ge chuck is its, self- ~ 15°JAW <i. Ct. PIPE JAW 10°JAW FIG.9- ROTATING-WEDGE CHUCK JAW PROFILES. FIG. 10- ROTATING-WEDGE CHUCK JAW TEETH SHAPE. FIG. 11- SELF-HOLDING SLIDING-WEDGE CHUCK JAW. 24 holdin g characteristics. TECHNICAL RESEARCH The use of rotatin g parts also tends to simplify and lighten the structure. The major disadvanta ge of a rotating-wedge chuck is that it is not inherentl y self-lockin g. A constant moment needs to be kept upon the jaws to keep them in c ontact with the pipe. This moment imposes an extra load upon the motor. chuck has several desi gn disadvanta ges. This type The jaws must be cantilevered from the spindle, requirin g heavy construction of parts. If an internal gear is used to rotate the jaws, the spindle gear must be mounte d on a very short bearing axis. If an external g ear is used, the housin g construction is complicated. An a u tomatic slidin g-wedge chuck has three jaws (usually) attached to t h e spindle by sliding means. The jaws are slid by the rotation of a scroll plate having a spiral thread machined on it. The motor may be connected (1) to the scroll plate and have the spindle restrained by friction drag, or (2) to the spindle and have t h e scroll plate restrained by • friction dra g. The friction force which a sliding-wedge chuck can exert is depende n t upon the following three major factors: (1) The ma gnitude of the tightenin g force. Since this type chuck is not inherently self-holdin g , the initial tightenin g force must be g reat enou gh to drive the jaw 25 TECHNICAL RESEARCH teeth deep enough into the pipe to overcome all working torque loads. (2) The shear strength of the pipe has the same effect on this type chuck as on the rotating-wedge chuck. (3) The jaw teeth shape must be such that a maximum amount of penetration is achieved by a given tightening force. The strength and wearing characteristics of the jaw metal, the amount of pipe surface scarring permissible, and the radii of the maximum and minimum size pipe to be gripped determine the final shape and area. The main advantage of a sliding-wedge chuck is its selflocking characteristics. The major disadvantage of a sliding-wedge chuck is that it is not inherently self-holding. design disadvantages. This type chuck has several The use of sliding parts tends to make the structure heavy and the machining difficult. The self-holding characteristic of a rotating-wedge chuck may be added to a sliding-wedge chuck by modifying one of its jaws as shown in Figure 11. ment of a o0 rotating-jaw. The rotating-jaw is a seg- It is attached to the sliding- jaw by a pin and flat spring as shown. The initial tighten- ing force will drive the rotating-jaw teeth into the pipe. As the working torque load is applied, the rotating-jaw will roll tighter against the pipe. Experimental design will be 26 TECHNICAL RESEARCH necessary to determine (1) the exact profile of the rotatingjaw to make it hold sufficiently and yet not bind the scroll plate too tightly to prevent easy opening, and (2) the jaw teeth shape so that the pipe may rotate but have no axial motion relative to the jaws. The addition of the rotating-jaw will reduce the magnitude of the initial tightening force needed to overcome a given working torque. SUITABLE MATERIALS AND NEW PROCESSES FOR PORTABLE PIPE THREADIN G MACHINE IvlAN l]FACTURE The materials investi gated for use in the Rotamatic pipe threadin g machine were: (1) Aluminum may be used for sand cast parts such as the frame, the carriage, and the diehead and cut-off mechanism frames. The characteristics which these parts should have are: (a) high impact resistance, (b) good corrosion resistance, (c) good machinability, (d) good castability, (e) good bearing qualities, and (f) high strength. No one aluminum castin g alloy has all these features. An aluminum-copper alloy contain- ing 4% copper plus ma gnesium and nickel is somewhat hot short, but has high physical and bearing qualities and good machinability. It is generally used in a . heat treated condition. An aluminum-magnesium alloy containing 10% magnesium combines high stren gth and 27 TECHNICAL RESEARCH elongation with good shock and corrosion resistance. machinability is good; its castability only fair. generally used in a heat treated condition. Its It is An aluminum- copper-silicon alloy containing 7.5% copper, 2.5% silicon plus zinc can easily be made from scrap and combines fair corrosion resistance, very s~od castability, and excellent machinability. It is generally used as cast. An aluminum-silicon-copper alloy containing 5.5% silicon, 4.5% copper plus zinc is a general purpose alloy having all-around characteristics and is heat treatable. (2) Malleable iron may be used where part size is limited and high strength is needed for such parts as the spindle and chuck housings. Malleable iron castings have high shock resistance, excellent machinability, good castability, good wearing qualities, and high strength. (3) Steel may be used in cast or rolled form. Alloy steel castings can be used in place of malleable iron castings for higher strength weight ratios. High-speed tool steel is used for the chasers, reamer, and cut-off wheel. The carriage guides may be made of high carbon or alloy steel. (4) Thermo-plastic plastics generally have limited use on a portable pipe threading machine. Cellulose acetate or pol-ystyrene,however, are very suitable for operation 28 handles. TECHNICAL RESEARCH Thermo-setting plastics may be used in the form of fabric impregnated with phenolic as mounting blocks for the motor to reduce vibration and noise. Parts of the electrical insulation of the motor and motor switch are made of various forms of molded phenolic plastic. New processes investigated for use in the manufacture of the Rotamatic were as follows: (1) Castin g small steel inserts in aluminum castings for increased wearing strength can be done with decided success. If the inserts are large, machining needs to be done on them after casting to insure correct alignment of mating parts. (2) Powder metallurgy forming of gears8 has the fol- lowing advantages: (a) lower production cost than cut and heat treated SAE 1040 gears, and (b) self-lubrication qualities of gears so formed. The gears used in the power cut-off mechanism of the Rotamatic are well adapted to being formed by this method. (3) Shot-peening of the chuck scroll plates, the diehead scroll, the motor gears, and the spindle for increased wear and fatigue resistance could be expected to raise the expected life of these parts several times over their life when not peened. 29 DESIGN STUDIES DiliSIGN OF AN IDEAL PORTABLE PIPE THREADING MACHINE The ideal portable pipe threading machine visualized by the designer is shown in Illustration 12. The construction of the machine would be light enough for one man to carry, yet there would be sufficient stability for operation when sitting unattached to a surface. The tools would be electric-power driven; the pipe would be held stationary. The machine would handle any pipe size from 1/8" to 2 11 , and any pipe length above 2 11 • All dies would be self- contained and could be selected by turning a dial on the outside of the machine. The appearance of this machine would be simple and suggest the nature of its work. There would be a minimum of protruding surfaces and controls. It would be amply-powered, of durable construction, be safe and simple to operate, and be easy to adjust and maintain. Its price would be around $600. The operation of t h is machine would be as follows: After a length of pipe has been indexed in the slot, the control arm is tripped to Position 1. The machine would then commence a cycle of gripping the pipe, cutting-off the unwanted length, threading and reaming the end, releasing the grip on the pipe, and coming to a stop. The threaded piece of pipe could then be removed from the machine. If it is desired only to thread an end, the end of a length of pipe could be indexed in the I 2 PI PE AN IDEAL THREADING PORTABLE MACHINE 30 DESIGN STUDIES slot, and the control arm tripped to Position 2. The machine would then commence a cycle of gripping the pipe, threading and reaming the end, releasing the grip on the pipe, and coming to a stop. The threaded piece of pipe could then be removed from the machine. This concept of an ideal portable pipe threading machine was used as a basis of further design and development. DBSIGNS OF PORTABLE ROTARY-TOOL PIPE THREADING MACHINES Preliminary design studies were conducted of five portable rotary-tool pipe threading machines. A turret machine having two turret positions is shown in Illustration 13a. It has a combination rotary self-opening die head and reamer, and a rotary power cut-off tool mounted on the turret. The pipe is held stationary in a vise, and the turret is mounted to rotate and slide on the machine bed. Fully automatic, this machine is a wo rl{ing version of the ideal machine p reviously described. With hand controls . to indes the turret it is an exceedingly fast machine. How- ever, the me chanical difficulties involved in getting power to the turret tools makes this machine unable to c ompete pricewis e with present portable machines. was therefore not att empted. Future development D E 13-PORTABLE PIPE ROTARY THREADING TOOL MACHINES 31 DE SIGN STUDIES A li ght-weight hand machine similar in q)pearance to an electric drill is shown in Illustration 13b. opening diehead. It has an automatic The threading torque is restrained by clamp- ing an extension of the machine frame to the pipe. A reamer may be mounted behind the diehead, or can be rotated by an electric drill. The hand threading machi~e could also be fit- ted with a rotary power cut-off tool for cutting off pipe. The main advantage of this machine is that it will replace hand tools in places where the worl{ can not be done on ordinary machines. The limited market which it would have was considered too small for further development. A machine rotating its tools by flexible shafts is shown in Illustration 13c. It can be placed on any convenient sur- face and the pipe clamped to it by an ordinary pipe vise. One of the flexible shafts drives the rotary diehead and reamer combination; the other drives the power cut-off tool. Both these tools can be clamped onto the pipe to relieve the operator from restraining the torque. The chief disadvantages of this system are the difficulties in using a flexible cable drive to deliver the hi gh torque loads needed, and the necessity of the operator havin g to mount the tools by hand. For these reasons this design was not considered further. A bench-mounted machine having two spindles is shovm in Illustration 13d. The pipe is held stationary in a slidin g vise 32 DESIGN STUDIES which moves between the two spindles. and reams; the other cuts off the pipe. One spindle threads The obvious disad- vantages of this machine are the expense of the two spindles needed, and the necessity of having to move the pipe between them. For these reasons this concept of a portable pipe threadin g machine was not considered practical for further development. A bench-mounted machine having a single spindle is shown in Illustration 13e. The pipe is held stationary in a vise and is inserted either into the spindle for threadin g and reamin g , or through the spindle for cutting-off. This machine was considered suitably workable for a more comphrens:tve engineering desi gn. ered: The followin g disadvanta ges were discov- (a) The method of removing the reamer for cut-off was extremely clumsy. Either it had to be inserted and removed by hand each time it was needed, or a rather elaborate retracting mechanism was needed to move it out of the way of the pipe. (b) The power cut-off mechanism as designed needed several impact elements in it. (c) A time analysis to cut- off, thread, and ream showed no great saving in time over present rotary-pipe machines. (d) Consumer preference in the sample market surveyed showed no great demand for this type machine. These design studies proved conclusively that in spite of the DES I GN STUDIES 33 ability of a rotary-tool pipe threading machine to thread bent or qurved pipe, it would be very difficult to produce a machine which rotated the three tools which could compare in price or simplicity with a machine which rotated only the pipe. For this reason, design studies of portable rotary-pipe pipe threading machines were undertaken. DESIGNS OF PORTABLE ROTARY-PIPE PIPE THREADING MACHINES A rotary-pipe pipe threadin g machine resembles a lathe in over-all configuration. The pipe is rotated by a chucking device mounted on the headstock. The cut-off mechanism, the reamer, and the diehead are mounted on a carria ge which slides on ways attached to the bed. This configuration is dictated by function, and the major variations possible are primarily in the desi gn of the component parts, and to a lesser extent in their location. The design of a rotary-pipe threading machine logically begins with the desi gn of the diehead mechanism, the reamer, and the cut-off mechanism. The confi gu ration and placement of these mechanisms determine the carria ge dimensions and the bed width. The motor, the spindle, and the pipe chuckin g device determine the dimensions of the headstock. A cutting oil system is required for the threadin g and reamin g assemblies. The frame is designed to mount the carria ge and tools, to 34 DESIGN STUDIES support the spindle and chucking device, to house the motor, and to include the cutting oil system. Following is a discussion of the design features of the parts of rotary-pipe pipe threading machines. Dieheads. There are three types of opening dieheads as il- lustrated in Figure 14: ( 1) a self-.contained diehead which has all of the chasers needed for threading any size pipe mounted in it; (2) a chaser and scroll diehead which uses a spiral scroll to open the chasers; and (3) a quick-opening diehead which is hinged in two pieces. The advantage of a self-contained diebaad is that all the chasers are in one unit eliminating the necessity of changing dieheads or chasers. The advantage of a chaser and scroll diehead is the simultaneous opening and closing ability of the chasers. The ad- vantage of a quick-opening diehead is the simple construction. With machines using chaser and scroll or quick-opening dieheads the greatest convenience is to have a separate mechanism for each size pipe. Reamers. There are two general designs of reamers as illus- trated in Figure 15: (1) burr, and (2) cone. A burr reamer is mounted behind the diehead and reams while threading. of ream depends upon the length of thread. reamer is needed for each pipe size. Depth A different burr Cone reamers are usually mounted ahead of the diehead and swung or slid out of place 0 0 0 0 0 0 CHASER ANO SCROLL OIEHEAO SELF· CONTAINE 0 OIEHEAO QUICK· OPENING FIG. 14-0PENING DESIGNS. DIEHEAD OIEHEAO BURR RE AMER FIG. IS-REAMER CONE REA MER DESIGNS. DESIGN STUDIES 35 when not in use. They vary in angle from 60° to 30°, and may be multi-fluted or have a replaceable blade. Cut-Off Mechanisms. There are two types of cut-off mechanisms as illustrated in Figure 16: (1) a wheel and roller cut-off in which a tool-steel cutting wheel pierces the pipe by a rolling and wedging action; and (2) a blade cut-off in which a single or multiple blades cut the pipe by removing metal. The advantage of a wheel and roller cut-off is its simple and durable construction. The advantage of a blade cut-off is its clean cut requiring a minimum of reaming. A cut-off mechanism may be made self-aligning about a pipe by mounting it on sliding guides. If it is mounted rigidly on the car- riage, adjustment for different pipe diameters must be made by hand. Carriages. The carriages of portable pipe threading machines usually hold the cut-off mechanism, the reamer, and the diehead mechanism. They may slide on flat or round cross-section ways, and may be moved by a rack and pinion or by a lever. If the tools are attached to the carriage in such a way that they may be rotated or slid out of the way, making-up fittings can be conveniently done. It is not desireable to attempt make-up work through the diehead because of danger of damage to the chasers. Make-up work can also be done outside the back end of the spindle by running the motor in reverse. SELF•AOJUSTING WHEEL a ROLLER CUT-OFF 0 MULTIPLE MANUAL-ADJUSTING WHEEL a ROLLER BLADE CUT- OFF CUT-OFF FIG.16- CUT-OFF MECHANISM DESIGNS. MANUAL-ADJUSTING SINGLE SLIDING-WEDGE CHUCK BLADE CUT-OFF ROTATING-WEDGE FIG. 17 - CHUCK DESIGNS. CHUCK 36 Chucks. DESIGN STUDIES There are two general types of chucks as illustrated in Figure 17: (1) a sliding-wedge chuck operated by a scroll plate which slides the gripping jaws, and (2) a rotatingwedge chuck operated by gears which rotate the gripping jaws. The three-jaw universal chuck, tightened by a key wrench, is the most common form of sliding-wedge chuck available. A uni- versal chuck may be made semi-automatic by extending the scroll plate beyond the circumference of the chuck housing and providing it with finger grips. The operator can then tighten the chuck by grasping the scroll plate while the motor rotates the housing. sent. Rotating-wedge chucks are not in wide use at the pre- They are readily adaptable to automatic chucking using the motor as a source of power. For holding long pipe a rear chuck or a bracket holder is desirable to keep the pipe in correct alignment with the spindle. Motors. There are two general types of motors which are adap- table for use on portable pipe threading machines: wound, and (2) induction. (1) series Compensated series, 110 volt, 15 ampere maximum input are the most common type. Induction mo- tors are usually 3 phase, 110-220 volts and are used on high speed machines. Motors may be gear-in-head, gear connected, worm connected, belt connected, or chain connected to the spindle. Transmissions, while desirable for speed are ex- pensive, and are not in general use on portable machines. 37 Cuttin g Oil Systems. DESIGN STUDIES A cuttin g oil system consists of a gear or vane type oil pump driven by a belt or gear from the main motor, an ou tput line leadin g to the workin g tools, a screenin g system to retain cuttin gs and strain the cu tting oil, a resevoir of cuttin g oil, and a s u ction line from the resevoir to the pump. Frames. Frames for portable pipe threadin g machines may be cast, or built-up welded structure. is desirab le to li ghten weight. The use of cast aluminum Handles are us ually pro- vided for ease in carryin g. Accessories. There are various accessories made for use with portable machine s . Amon g them are collapsible pipe stands, wheeled stands, auxiliary s u pports for lon g pipe, nipple chuck s, and universal drive shafts to drive geared dieheads for threading pipe up to 12 11 nominal diameter. 'rhe above studies of the design features of portable rotary-pipe pipe threadin g machines indicate that a wide vari a tion in structure is possible. The exact combination of features se- lected is a choice based on the economic and en gineerin g requirements under wh ich the machine is bein g designed. 38 THE FINAL DESIGN BASIS The design of the Rotamatic pipe threading machine is based on the results and conclusions of the market investigation, the technical research, and the design studies perfonned. Production, sales, and operation requirements of portable pipe threading machines were considered simultaneously throughout the design. The final design of each of the parts of the Rotamatic is the result of consideration and compromise between the following elements: (1) Sufficient strength and power requirements. (2) Low material and fabrication costs. (3) Simple maintenance and accessibility. (4) Essential safety considerations. (5) Over-all utility and operation convenience. (6) Inherent attractiveness of form and surfaces. (7) Special sales and advertising features. CONSTRUCTION The Rotamatic pipe threading machine is shown in front views in Illustration 18, in rear views in Illustration 19, and in pictorial orthographic in Figure 20. The machine is composed of the seven mechanisms described in the following paragraphs. A schedule of the drawing numbers referred to is tabulated in Appendix B. ROTAMATIC 18. ROTA MATI C - FRONT ROTAMATIC I VIEWS . 19. ROTAMATIC - REAR VIEWS / I I -j FRONT I --22.t)O- --- --- ELEVATION II \_ C(/T-OFF '/ -· - - WHEEL C/1.k'RJ,,,.t,::;E P0.:5/TION/,1/~ COT-OFF FE££JSCREW' XNOB MECHANISM --- ---- CA££/A6E -- OP£RAT/AIG HA/V£>L.E. 1WmMECHAN~ ' CARl?IAGE .E..OZNYM L , , -M~ 7------ - I 20. S:,& -1 _J 4r MANVl'ACTl4/1E,e) #AMEPLATE HOUMATIC PKTO£/AL _,,,.~...,.,R-000 CALIFIIIII IISTfflTMUlltlNY ,--: RIGHT £NO £ZEYATIOIV' -1225 20.7.f OVER~,ALL. W/OTI/ --- - -- 5 LEFT -E~~ EL£Y~T/O~=J p -- - - - -- - - FIGURE - \ \ ._____ FRtJ/VT cA.ee1.AcE GI./IV.£ _ 0B Jlj - \ \ '--- 1. . . , . . - - - - ~ \ ,--+- _:_-~ i \ \ CA,eRY/NCr NA/VOLE \- Ir /V,1 '1 -I _J __ J _ _t_ I HEIGHT , a/J~ r - · - /?EAR C,ARRl,A6£ Gillt)E I~ -(R~ I, - --L_____ - - - - io.m- -- -- ··1 550 tf 1 r---- 14:00 CARRIAGE TRAVEL--- -, VIEW 3 r L ' ~- I -- - R£AMER -ITT-I - U------+- -----~L...-- 1 :~ --/'!__ / ,·,,,uo, I OOTL.£T ~ - -REAR ALIG,1-//N,S- C~ ✓IJ"'I( - £1.-E'CT.f:'ICAL __/ -7 / - FRONT ~/?!?PIN-"= - - - - - - - - - - - -- --.f,2,50 OVER-ALL /..E.NGTH- -- -- - - - -- - ·-- • i--------1-F.5'. ~ TOP ASS.EMBLY L _ THREAO/,YG -==-==~1° ' f---lZ75 C&VTER TO CDITER Clit/CX 1---- CHlC'K Ol?Cli?/17NG HAl{t:>/..E SOLT HOLE AfOVNTI/VG' CAUYIIV'<7 HANOLE / ~__ '\, Cl/TT/NG 0/L FL...EX'/8L.E H0.5.E- / - 39 THE FINAL DESI GN The threading mechanism is composed of two major assemblies, the diehead threading assembly (Drawin g R-010) shown in Figure 21, and the diehead frame assembly (Drawing R-020) shown in Figure 22. Six threading assemblies are furnished with the Rotamatic to thread pipe from½" to 2 11 in diameter. Bolts up to 1¼11 in diameter may be threaded by the use of bolt chasers mounted in the threading assemblies. The 2 11 pipe diehead threading assembly is shown in Figure 21. It consists of a steel stamping front plate; a steel stamping back plate; 4 steel chaser guides; 4 hobbed, high-speed tool steel chasers; and 4 spring steel chaser sprin gs. to the back plate. The chaser guides are welded The chasers slide easily in the guides, but are held in an open position by the chaser springs when the threadin g assembly is not mounted on the machine. The cantilever construction of the chaser guides prevents clogging by chips such as occurs in quick-opening dieheads. The front plate is connected to the back plate by two 3/8" cap screws to allow for varying the thread diameter by rotating the back plate in respect to the front plate, which will allow the chasers to enga ge the operating scroll at a different point when the threading assembly is mounted on the torque pins. Bushings are provided around the front plate mounting holes to add ri g idity. The radius of metal around these holes allows the threadin g assembly to be locked onto the f ' j /" /IEX HP. CAP .5Cff W- j -2~ N,C-3 5 '·;-~ 0£5/GNAT.£ .2".P/P£ ,5/ZE, 0TH£R ,.:1/Z,,E NO4f8£€'S .5/it'WN ON ~H.EPVL.£ . z ClLIFORlll llSTITUTE .. TECHIOLBSY 1-C"==--=•:•c..,•_,_ _---l FIGURE 21. : I' r, j - - - r l, -"7_' . =~____, ____ ,_ - ;'T( !' I- - - -rLL- 1 I I ' r - - - OIEHEA£J 77/REAJJl ASSEMBLY •.,.~ __, R-0/0-F ~ - ' ..J I I'----iI ' I I I ___ .,/ ~- - - ~~i'l) ------- ~ ~~' HLIFIHII IISTITUTM£CHILIIY .._:_-_::________, FIGURE 22. LJIEHEA£) FRAME •• A.5S£A.fBLY H- 020 40 THE FINAL DESIGN diehead frame assembly when the chasers are closed. The diehead frame assembly shown in Figure 22 consists of a cast aluminum back plate, a cast aluminum front cover plate, a cast aluminum rear cover plate, e. cast steel operating scroll, a cast steel scroll washer, a steel st~mping toggle link, a cast aluminum toggle arm, a steel stamping loc1cing lug, a steel and plastic operating handle, and two steel torque pins. The toggle linkage which raises and lowers the chasers of the six threadin g assemblies is mounted on the diehead frame assembly. An 80° rotation of the operating handle rotates the scroll through 33° and moves the chasers .210 11 • The lobes of the scroll are interrupted for ease in fitting the threading assemblies onto the torque pins. The lobes are rounded on their interrupted ends so that when closed, they will easily enga ge the chasers, and push away any chips which might be in the chaser slots. A locking lu g is at- tached to the to ggle arm which rotates in front of the threading assemblies and holds them in place on the torque pins when the chasers are closed. The bushin gs on the threadin g assemblies' front plates will not allow them to slip off the torque pins even thou gh they are held at only one pin. The front cover plate adds rigidity to the attachment of the diehead frame assembly to the carria ge. The rear cover plate is used as a stop for the diehead mechanism wren raised in make-up position. There is sufficient cut out in the cover 41 TB""E FINAL DESI GN plates for full visibility of the pipe and for chip disposal while threadin g . Toe torque pins are screwed into the back plate and carry the threadin g torque load from the diehead threading assembly to the diehead frame back plate. The toggle arm rotates about the front torque pin and is restrained from sliding off it by a shear pin. The male guides machined on the back of the back plate enga ge the cut-off mechanism female guides. 'rhe s cro 11 washer is threaded into the back plate. The cut-off and reaming mechanism is composed of two major assemblies, the cut-off tumble gear assembly (Drawing R-030) shown in Figure 23, and the cut-off frame assembly (Drawing R-040) shown in Figure 24. The cut-off tumble gear assembly shown in Figure 23 consists of a cast aluminum back p late, a steel stamping tumble plate, a steel and plastic operating handle, 2 gear and roller combinations, 1 large steel intermediate spur gear, 2 small intermediate spur gears, a steel spur and bevel gear cluster, and steel pins for these gears. The tumble gear assembly uses the torque of the rotating pipe to drive the cut-off wheel into the pipe. When the operating handle is moved downward the bottom roller contacts the rotatin g pipe. This sets in motion the lower gear train which drives the cut-off wheel against the pipe at a rate of .052 11 for each revolution ,;;_-;;0 , ____, £".JJ .~ · .t,_o,2 FIGURE 23. FIGURE 24. ,-. -,,v;_; 7':,..,3,_ ~- ;..j _,. -E ~ CUT-OFF TUMBLE :':::;_:'-"~u GEAR ASSEMBLY l?-030 CVT-OFF FRAN£ ~u:;;~:;;2~==:::l ASSEMBLY R-040 42 of the bottom roller. THE FINAL DES I GN When the operatin g handle is moved up- ward, the top roller en gages the pipe, setting in motion the upper gear train which moves the cut-off wheel away from the pipe at a rate of .104" for each revolution of the top roller. A small ball bearin g mounted in the back plate keeps the tumble plate in a neutral position when not in use. The fe- male guides on the back of the back plate engage the male guides on the back of the diehead mechanism. The center hole in the back plate is to allow pipe to pass throu gh it for cuttin g-off, and the rear hole is to allow the pipe to pass throu gh it for reaming. The cut-off frame assembly shown in Figure 24 consists of a cast aluminum frame, a cast aluminum sliding block, a tool steel cut-off wheel, 2 steel cut-off rollers, a steel feed screw, a cast aluminum feed screw knob, a steel feed screw bevel gear, steel wheel and roller pins, and a tool steel cone reamer. The steel guides for the sliding block and the steel insert bushi ng for the feed screw bevel gear are cast as inserts in the frame. The two rollers align the cut-o.ff mecha- nism about the pipe. The feed screw has a½" NC thread. The feed screw bevel gear threads onto the feed screw and engages the bevel gear of the tumble gear assembly. knob is used for three purposes: The feed screw (1) to move the sliding block by hand if it is not open far enough to allow a pipe to be inserted through the cut-off frame; (2) to rotate the cut- 43 THE FINAL DESIGN off and diehead mechanisms out of the way of the pipe for make-up work; and (3) to slide the reamer into place for reaming. The reamer has a 60° included an gle and is mounted on the rear of the cut-off frame. When slid in place it is approximately 1½" behind the threadin g chasers. This posi- tion in rear of the chasers enables it to be used with more convenience and speed than if it were mounted in front of the diehead. There is sufficient clearance for full visibility of the reamer when in cutting position. The carriage assembly (Drawin g R-050) shown in Figure 25 consists of a cast aluminum frame, 2 steel carriage slides, and a steel carria ge rack. It supports the diehead and cut-off mechanisms by a bolt connection in the rear and a locking block in front. The slides slide on the top and grip on the bottom of the main frame guides. of carriage travel. The rack is 1511 long to allow 14" The bolt attachin g the tools to the car- riage is on the same horizontal center line as the spindle to avoid a force couple which would tend to twist the tools relative to the carria ge. The automatic chuckin g device ( Drawing R-060) shown in Figure 26 consists of a cast steel front chuck housin g , a cast steel front chuck scroll plate, a forged steel front chuck master jaw, 2 steel front chuck jaws, a cast alum i num rear chuck housing, a cast aluminum rear chuck adjustment plate, a cast \ p • BUR#EA/? lhV/<W' ~ '/ I ·," r $/ I j" ,&""/LL/JrEe #P. 5C,e.t:·w -j.e.9/V,,&:-J f.,X .J" C.5-< /IP. 5CRLW #-2BNF·3~ ~ -- 1-- ' - _j' _ _ _ _ I '---+ - - - - i - - --+ - \ i ::,_:-, > / ' ,,-- ....... WG I 1-.-.J ... ~ I ,...,,_..L ....... ~ Ff1 - 1-- CARl?IA6£ ASSEMBLY CUIFUIIA IUTITUTE-TECHIILIIY ~ " PUT --1 +J - -1- - '- - - -_-i-_- + - I \ FIGURE 25. - -- -- -t-- - - - - - - - - -- - J r✓ J ----0:_~~~ L,1-,' I ) I I \ I I I ' I I I I • + )j - --- - I I I I I I I - 7- --·-r-~-- -- - 7 \ I \ I I I I \ 44 THE F'INAL DESI GN steel rear chuck scroll plate, 3 steel rear chuck jaws, a cast steel outer spindle, a cast steel inner spindle, a cast steel spindle gear, and 2 extra-light ball bearings. The front 3-jaw sliding wedge chuck grips the pipe while the rear chuck keeps it concentric with the inner spindle. The housings of the two chucks are connected to the inner spindle. scroll plates are connected to the outer spindle. gear is keyed to the outer spindle. The The spindle The ou ter spindle rota- tes on extra-light ball bearin gs which have seal rings and can be lubricate·d by fittings provided on the frame. is carried by the front bearing. Thrust An adjustment plate is pro- vided on the rear chuck scroll plate to allow the setting of the rear jaws to be the same as the front. The driving torque is transmitted from the spindle gear, through the key to the outer spindle, through three shear pins to the front chuck scroll plate, through the teeth to the front chuck jaws, and throu gh the jaw serrations to the pipe. The transmission of torque throu gh the front chuck is different from conventional universal chucks which transmit the torque from the spindle, to the chuck housin g , to the jaws, and to the pipe. The in- ner spindle carries no torque loads. 'rhe action of the chucks and spindle for chuckin g pipe is as follows: After a piece of pipe has been inserted through the inner spindle, the operating handle is moved to the "close" position which starts the motor. The friction dra g linka ge ¢ I t R-064 1\_:-;,_o~ __ / / / .,,;,rr:eA £/G,#T OAl.,L, 8EAR/N6 ,YO, J,t,,24/ ...YLW' PE,PA,e lt/£6 ,r '- -· - ~~- 1 i -ae ) ,;-;:,;_>- - . (£- 6"':-J ,e. £YTR.4,Ll6#/ BA-GL, l},EAelNG Nv', OL.24 ,,y.ew L?E.P,Aeruek R.-059 ) '"' -,,, '-- "' --- -- ' f R-ose; J ~ ,.,.,,,, /, if ----;;- SPJVfJLE l CflUCr. ~ _ __ ASSEMBLY I R-060 /::P ✓»/ /;/ I I I I # I; ,,, \\~ ~:\ , ',~ ~ -~::::.-,~ ----:::~ -.. -===~ --i--- FIGURE 26. ( R-0.:2 ) - ~✓ -✓~--·- ~ ~ £ - ~ ,;~J ~- 45 THE B7 INAL DE SI GN shown in F' igure 29 (Drawing R-090) will restrain the front chuck housing from rotation, allowin g the spindle gear to rotate only the outer spindle and scroll plates, which will cause the front and rear chuck jaws to close. When the front chuck jaws are tightly closed upon t h e pipe the brake will be gin to slip as the inner spindle rotates. This will impose a load on the motor, and t h e spindle will slow down. operating handle is t h en moved to the 11 The run 11 position which causes a. cam to lift the brake shoe and allows the full power of the motor to rotate the pipe. The rotatin g pawl on the master jaw of the front chuc k will g rip tighter as the working torque load upon the pipe increases. The action of this type jaw is described in detail on pa ge 25. The action of the chuck s and spindle for unchuckin g pipe is as follows: When the operatin g handle is moved to 11 open 11 the brake s h oe is allowed to bear again st the front chuck housing and the motor is reversed. The scroll plates will rotate in reverse and open the front and rear chuck jaws. When the jaws are sufficiently clear of the pipe, the operating handle is moved to "off 11 and the pipe can be remove d from the inner spindle. If it is desired to stop the machine and not remove the pipe, the operatin g handle can be moved from 11 run 11 to 11 off 11 • This will cause the brak e to bear a gainst the front chuck housing, and the motor to be turned off. chuck will not release its g rip on the p ipe. 'rhe front 46 THE FI NAL DES I GN The motor assembly (Drawin g R-070) shown in Figure 27 consists of a series armature, a series field, 2 brush assemblies, a cast aluminum fan, a cast steel motor end bell, a cast steel motor housin g, a cast steel gear case, a steel helical motor pinion gear, a steel helical cluster gear, a steel helical final gear, a steel spur pinion gear, 2 steel gear shafts, 4 gear shaft ball bearings, 2 motor armature ball bearin gs, a steel stamping switch lever, a Furnas electric switch St y le 1-143, and a Hubbell 3-prong 15 amp. twist lock socket. The motor specifications are: 2-pole compen- sated series winding, 110 volts, 3.5 amp. no-load current, 15 amp. full-load current, 7500 rpm no-load s peed, 5400 rpm full-load speed, 65" if startin g torque. Heat-treated steel, helical gears are used in t he gear case which give an overall reduction of 1 7-1 in two steps of 4-1 and 4 .25-1. The spindle gear reduction is 8-1 giving a total reduction of 136-1, wh ich mak es the no-l o?d spindle speed 55 rpm and the full-load speed 40 rpm. The motor armature and the gear shafts are mounted on ball bearings. The mo t or and gear case are sealed and require no l ubrication in service. The spur pinion which en ga ges the spindle gear requires only occasional greasin g. The rear motor mounts which restrain the motor torque have fiber bushings to minimize vibration and noise. The front motor mount is a steel bushin g which fits on the spur pinion gear shaft. The electric switch is an on-off- ~ ~ c:e:.-;z) - 7~_ } ~ '- - --- --- --\ 7 ( R-0 :__) ~ ~ Q ( R -o:--~ J (e -o7? )---- ' _______,.,,,/ / ', I F-~__:7 I : I I , I J I L" I , _,_1-...,, . = pb I, #VBIJ£,LL 3-?.;.'&Al<J. ( ,e---:;;&__'j ( R;'."~) "-, Ft//.:tVA.f EL.LC Th'/C .5W /TCH 5TYLE ,L.-/43 rw,_;;r LOt;.e 5CX /.4T I '- FIGURE ~ 1, 27. \~, I ~ -"'_-'.?(_i 'I\ ---,~~~- ~;-:~ "-, ,, ,, \\ I/ I' ~\\ f!;-~t· \ '// i- ,1 / , I, / - ~ -(e-~,e ) MOTQI? ASSEMBLY R-070 ClLIFDllll llSTllm-rmnun ,-·-::_ ==-; .,:_/,, I~ 47 THE FINAL DESIGN reversin g switch of½ HP rated capacity. throw of 60° from reverse to forward. It has a total It is mounted on the gear case where it is fully shielded a gainst any oil V\hich the pinion mi ght throw on it, and is operated by an extension of the chuck operating handle. The 3-pronged twist lock electrical socket for connectin g t h e power cord is locate d on the rear of the machine where it is out of the operator's way. The cuttin g oil system (Drawing R-080) s h own in Figure 28 consists of a sheet metal sump, a perforated metal tray, a vane oil pump, a pinion gear, a suction line, an ou tput line, a neoprene flexible hose, a valve bolt, and a diehead line. The sheet metal sump has a 2.5 quart capacity of cut- tin g oil. A ridge is cast in t he frame where it meets the sump to restrict the flow of cuttin g oil down the ins i des of the frame. The perforated metal tray is fitted with handles for convenience in removin g for cleaning. The va ne pump is driven by a pinion gear meshing with the spindle gear. Cut- tin g oil is picked up from the sump throu gh the suction line. The output line exten ds from the pu mp to a bulkhead union on the frame midway between the extremes of the carria ge travel. A piece of neoprene tubin g with fittin gs on each end runs from the frame bulkhead union to the carria ge bulkhead union. The carria ge is drilled, and t h e bolt which connects the diehead mechanism to the carria ge is hollow and equipped vvith a union : f-------- - - - r / ~r----~ - (X) N w 0::: ::J <.9 LL I. ., ., 0 ¥ ij .... ., ~ 0 ¥• 0-,0 vO <.. ~· Og .:, ~ '-. , 1 11 ,. I'll.1,, I '" I \__, ,.,,.,..__._..~ _ : I 'I -+-_,L; I 000 zii!H ® l : LL_L L - --+----------------.___Jj ' I i1 c1:i~t=J2-y I _ _ _ _ _ _ __ ___J 48 on its head. THE FINAL DESIGN The diehead line extends from the head of the bolt inside the rear cover plate to a point directly over the chasers. When the diehead and cut-off mechanisms are ro- tated to make-up position the bolt will rotate with them and stop the supply of cutting oil to the chasers. The frame assembly (Drawing R-090) shown in Figure 29 consists of a cast aluminum frame, 2 steel carriage guides, a cast aluminum brake shoe, molded asbestos brake lining, a steel stamping brake adjusting link, a steel stamping brake tripping link, a steel cam, a steel and plastic operating handle, a spring steel brake spring, a steel spur gear and shaft, an aluminum carriage positioning wheel, and two tubular steel carrying handles. The frame is cast in one piece with the parting line along the vertical center line of the spindle. The name of the Machine, the chuck operating handle positions and slot, and the motor cooling slots are part of the casting. The brake shoe is located so as to bear on the front chuck housing, and is rigidly connected by a bolt to the adjusting link. The molded asbestos lining is unaffected by the cut- ting oil. A set screw in the tripping link bearing against the adjusting link varies the angle between the brake shoe and the tripping link to compensate for wear of the lining. The compression spring pushes against the tripping link so as to keep the brake shoe tight against the front chuck housing. Spring pressure may be varied by adjusting the length of the l§ ! ! : •l •~~ f-+-+++-t-+-f-+-H f-+-+++-t-+-f-+-,t-rl I~ * ~~ \ 11 \ -~ ,- ~a ~ l( ~ ~ : >-e-t-+-+-+-+--+-f-+-C'H ~ ~ ~n,,~ .. "'~l, 5 0) C\J I w -t-,-- (-:_·J,/, 0::: ::J <..9 ) •/ -{_.!z ' LL ------J._ - '-.J____,..,' i G I I I ~ f-+,L-,1._:_,___-+--~::;TAT: y I I - - I _ -_:_ -=== -=- ~ --=---'-'--"'m~-- THE FINAL DESIGN 49 bolt running through its center. is welded to the cam. lugs on the cam. The chuck operating lever The motor switch lever engages two A 30° downward movement of the operating lever will turn the motor on. An additional 30° downward movement will cause the cam to bear against the tripping lever and the brake shoe to lift off the front chuck housing. The center of the cam is displaced from the center of the motor switch to allow for this overtravel. The chuck operating lever moves through a total arc of 90°. By having the operat- ing lever lift the brake there is less wear to the brake lining, and a large proportion of the motor torque may be used to close the chuck jaws. The carriage guides are heat-treated ground steel whichare bolted on both ends to the frame. allows 14 11 of carriage travel. The length of the guides The carriage positioning pinion, shaft, and wheel are mounted on the frame. Tubular steel handles are provided on each end of the machine for carrying by two men. Mounting bolt holes are provided in the horizontal feet on each end of the machine. The Rotamatic final assembly (Drawing R-100) shown in Figure 30 consists of 6 diehead threading assemblies, a diehead frame assembly, a cut-off tumble gear assembly, a cut-off frame assembly, a carriage assembly, a spindle and chuck assembly, a motor assembly, a cutting oil system, and a frame assembly. (i_o t o ) - o ---1r-- ··- --- - -- - - --- --- -\ · --- ' ' 0 F -· ') -· ( ,e-_o= (.R_ o_ 20)--\_ . \__ - - R - 010 1··~ £-tJ3C ' ,/ l]'.~ -- - C r ,- --(To~;;'] _] L- - - ~ - - - ~- ~ --= l- _::-:_:-_~ =. -= -=-=.. //' ' _) _-_ -- ..- --l··') ' "" / ) FIGURE 30 . _"I 0 ~-,~ 0 -- - r·-: -, ~ ~ c:;,~ ~ -- ·· - -~ lit:JTAUITlC ..~-"; FINAL ASSE.WJLY i-J?-°IOC' ClllFIHIA IISTITITE•TEIIHLNT :::::: \ ~ ;.:;.;~-- \ THE FINAL DESIGN 50 The inside and outside surfaces of the frame, carriage, diehead mechanism, and cut-off mechanism are sprayed with grey lacquer primer. The outside surfaces of these parts are given two coats of a light warm grey lacquer. The machine name, the chuck operatin g handle positions, the front of the cutoff feed screw knob, the front of the carriage positioning wheel, and the two carrying handles are painted black. The manufacturer's name plate is attached to the left end of the machine. The diehead threadin g assembly is mounted on the torque pins of the diehead frame assembly which is bolted to the carriage assembly by the special oil valve bolt. The cut-off tumble gear assembly is bolted to the cut-off frame assembly. The cut-off mechanism will slide against the back of the diehead mechanism. The spindle and chucks are assembled through the frame bearing holes with the frame in an upside-down position. The motor is fitted into place from the bottom of the frame and held by two bolts in the rear and by the pinion shaft bushing in the front. The motor wiring is passed under the spindle and connected to the twist lock socket. The oil pump is mounted in the frame and the suction and output lines connected. The oil sump and tray are fastened to the frame. The carriage is fitted on the guides and the flexible oil line is attached between it and the frame. •rhis completes the as- sembly of the Rotamatic pipe threading machine. 51 THE FINAL DESIGN OPERATION The Rotamatic may be operated on a bench, on a wheeled stand, on the bed of a truck, or on any convenient working surface. For best results the surface should be smooth and level, and the machine should be fastened to it with care that there is no twist in the bed. Height of the carriage positioning wheel should be between 30 11 and 36 11 above floor height for maximum comfort and ease of operation. Electric power may be obtained from any 110 volt line fused for 15 amperes or higher. For maximum safety a ground con- nection should be made if the circuit does not provide it. The electric power cord may be disconnected from the back of the machine for convenience in moving. Approximately 2. 5 quarts of cutting oil should be in the· oil sump for operation. The perforated metal tray should be clean of chips. A pipe support should be used whenever a long length of pipe projects from either end of the machine. Very short nipples can be threaded by using a nipple chuck. Pipe up to 12 11 nomi- nal diameter may be threaded and cut off by use of geared tools driven by a universal extension shaft. Chucking is done by placing a piece of pipe in the spindle so that the position where it is to be cut off falls approxi- THE FINAL DESIGN 52 mately midway between the ends of the carriage guides. The chuck is closed and the motor turned on by pulling the chuck operating handle downward to the 11 close 11 position. After the jaws have gripped the pipe tightly, it will begin to rotate and the motor will slow down. handle is then moved to the 11 The chuck operating run" position which will re- move the load from the motor. Cutting-off is done by moving the carriage so that the cutoff wheel is at the position desired. The cut-off operating handle is pulled towards the operator. This motion will con- tact the bottom roller of the tumble gear train to the pipe and the cut-off wheel will move towards the pipe. The Rotamatic is shown performing the cut-off operation in Illustration 31. Time for cutting off 2 11 pipe is 6 seconds. For pipe sizes below l½" the gear train will drive the cutoff wheel into the pipe without having to lift the operating handle. For l½" and 2 11 pipe the operating handle will have to be lifted periodically as the wheel is cutting off to avoid stalling the motor. After the pipe has been cut.:.off the cut- off operating handle is moved away from the operator. This contacts the top roller of the tumble gear train against the pipe and backs the cut-off wheel away at high speed. Threading is done . by moving the carriage away from the end of the pipe far enough to clear the diehead. The chasers are 31. ROTAMATI C 32. THREADING CUTTING - OFF OPERATION 53 THE FINAL DESIGN closed by pulling the diehead operating handle towards the operator, and ·are started threading by moving them against the end of the pipe by means of the carria ge positioning wheel. Once started, the chasers alone will move the car- riage. Cutting oil is fed in a steady stream directly over the chasers. The Rotamatic is shown performing the threading operation in Illustration 32. 20 seconds. Time for threading 2 11 pipe is When sufficient thread has been cut, the chasers are lifted by moving the diehead operation handle away from the operator. Reaming is accomplished by sliding the cut-off mechanism towards the operator by grasping the cut-off feed screw knob. The reamer is then moved against the end of the pipe by the carriage positioning wheel, until it has cut away a sufficient amount of pipe metal. The Rotamatic is shown performing the reaming operation in Illustration 33. Time for reaming 2 11 pipe is 4 seconds. Making-up a fitting is done by moving the carriage away from the pipe far enou gh for the reamer to clear, and rotating the diehead and cut-off mechanisms away from the carriage, by lifting the cut-off feed screw knob. When in this position the flow of cutting oil to the diehead will stop. Caulking may be applied to the thread of the rotating pipe and a fitting screwed on by hand. The Rotamatic is shown performing t h e 33. ROTAMATIC 34. MAKING-UP REAMING OPERATION 54 THE FINAL DESIGN making-up operation in Illustration 34. 2 11 pipe is 15 seconds. Time for making-up After the fitting is on finger tight, the chuck operating handle is moved to the 11 off 11 position and the fitting is tightened with a wrench. Unchucking the pipe is accomplished by moving the chuck operating handle to the "open" position. vVhen the jaws have opened sufficiently, the chuck operating handle is moved to "off". The motor will stop and the pipe with the fitting on it may be removed from the front of the machine. The diehead and cut-off mechanisms are rotated back into place on the carriage and the Rotamatic is ready for another piece of pipe. Changing dieheads may be done by merely pulling the diehead threading assembly off the torque pins when the diehead operating handle is in an open position, and slipping another size diehead in place on the pins. Closing the chasers locks the threading assembly onto the diehead frame. CONCLUSIONS The pipe threading machine designed as a result of this thesis study fulfills a large portion of the present need for portable pipe threading machines. The Rotamatic is an attractive, durable, light-weight, high-speed machine which is convenient to operate, easy to clean, and simple to maintain. It is cap- able of threading, reaming, cutting-off, and making-up 55 THE FINAL DESIGN fittings for pipe between ½" and 2 11 diameter. It can thread bolts up to 1¼11 diameter, and thread and cut-off pipe up to 12" diameter by the use of a universal extension shaft. 'rhe Rotamatic offers the following improved features over present portable pipe threading machines: (1) Separate threading assemblies for each size pipe, but only one diehead operating mechanism mounted on the machine. This arrangement substantially lowers the cost of the threading assemblies. (2) A cut-off mechanism which is power-driven by the rotating pipe for increased ease and speed in cutting off pipe. (3) A reamer which is mounted behind the diehead for increased speed and convenience of use. ( 4) . A positive gripping automatic chucking system which simultaneously grips and aligns the pipe saving operator time and effort. The design of the parts of the Rotamatic were determined by the designer as being the best for the job required without regard to any particular manufacturing plant facilities. With minor modifications the machine could be adapted to be made by most of the present day portable pipe threading machine manufacturers. The final design, as presented, is free of mechanical 56 THE FINAL DESIGN interferences that coul d be checked by the building of the wooden appearance model. The structure is sufficiently strong to carry the design loads chosen as a result of test and reasoning. Before actual production, an experimental working model will need to be built to eliminate the mechanical and structural difficulties which will surely arise. 57 APPENDIX A APPEARANCE DESI GN CONSIDERATIONS . 'l'he appearance desi gn of the Rotama tic was done simultaneously with the en gineerin g desi gn. The basic characteristics which the designer considered the Rotarnatic needed appearance-wise were: (1) A form su ggestive of a light-weight, yet sturdy and powerful machine. (2) Surfaces with a minimum of protrudin g parts. (3) A durable surface finish suggestive of precision of design and construction. (4) As few controls as possible organized into convenient groups for operation. The design of the diehead and cut-off mechanisms began by assuming them to be housed within a rectangular form. This shape was modified to reduce the mass and to save material. The diehead and cut-off frame castin gs were tapered both for ease of drawing when bein g cast and to further lighten the mass. They were desi gned so that when closed, the guides be- tween them are invisible. tion to either castin g. This was possible Vl!i.th no complicaThe diehead toggle linka ge and the cut-off tumble gear assembly were desi gned to fit within the outside form. Placin g the reamer inside the cut-off frame was a convenient way of organizin g it within the basic form. Ample cutouts were made in the top of t h e castings for vision. The die h ead and cut-off mechanism operat i ng han d les were APPENDIX A 58 organized so that when the diehead was closed and the cutoff mechanism was in neutral position, the handles would be parallel and at an angle of approximately 65° to the horizontal for ease in grasping. A thermo plastic knob was used for the knobs for warmth and color. Because of the relatively low production of the machine a spherical knob was used. However, a more comfortable form could be designed if thought economically feasible. The cut-off feed screw knob was rounded in the back for comfort in pulling, and knurled on the surface for friction in turning. The carriage was designed in a straight-forward way to carry the diehead and cut-off mechanisms. Its dimensions were de- termined by the dimensions of these mechanisms and the length of travel desired. The center extension which holds the rack was made with straight lines to avoid giving a feeling of direction away from the carriage. The frame design was begun after the dimensions of the motor, the spindle, and the chucks had been definitely determined. The half-scale visualization model shown in Illustration 35 was constructed. It contained the motor, spindles, chucks, carriage, and diehead and cut-off mechanisms. Since the die- head and cut-off mechanism operating handles were asymetrical elements about the center line of the spindle, it was considered best to mount the motor asymmetrically towards the front. If 3 5. ROTAMATIC HALF - SCALE VISUALIZATION MODEL. APPENDIX A 59 the motor were placed above or below the spindle the over-all height of the machine would be raised, which would require more metal, increase the weight, and raise the silhouette. If the motor were placed to the rear of the machine the operating handles would cause asymmetry in one direction and the motor in the other. Half-scale elevations of the frame were made, and perspective sketches were made from photographs of the model. Finally, the visualization model was covered with modeling clay to the form desired to check the sketches. In the final form of the frame the headstock was tapered to lighten the mass and to form a pleasing transition from the large front chuck to the small rear chuck. Small radii were used on horizontal plane intersections, while larger radii were used for vertical plane intersections to accent the horizontal lines of the machine. The angle of slope of the bed sides was made the same as the angle of slope of the headstock sides. The large protrusion which was needed for the motor gear case was used to mount the chuck operating handle. The off-center position of this handle was balanced by the position indications cast into the metal. The handle was made to operate in the same direction, and of the same dimensions and material as the diehead and cut-off mechanism operating handles. The minor protrusion to clear the motor housing was textured with horizontal cooling slots. The name of the machine was cast into the metal and placed on a 60 prominent part of the headstock. APPENDIX A The manufacturer's name plate was mounted on the left end of the machine underneath the rear chuck. The twist-lock electrical outlet was placed in the rear of the machine out of the way of the operator. The ear- riage guides were dropped¼" from the top of the frame ways so the carriage would appear to be well consolidated with the frame. The carriage positioning wheel was made to repeat the cut-off feed screw knob and was provided with finger grips on the back to give positive gripping action for reaming. Handles were provided at both ends of the machine for two-man carrying since, because of the asymmetrical position of the motor, it could not be carried satisfactorily by a pipe through the spindle. A horizontal foot running the width of the machine was provided for its support and fastening. The color scheme was chosen because it is attractive in any setting, and does not show grease stains excessively. The frame, the carriage, and the diehead and cut-off mechanisms are painted a light, warm grey. The carrying handles, the inside of the feed-screw knob, the inside of the carriage positioning wheel, the chuck operating handle positions, and the name of the machine are painted black. The spherical knobs on the chuck, diehead, and cut-off mechanism operating handles are dark red. The rear chuck, the front chuck, the diehead threading assemblies, the stems of the three operating handles, and the rims of the feed screw knob and carriage positioning wheel are natural metal finish. 61 APPENDIX B ROTAMATIC DRAWING NUMBER SCHEDULE R-000 Rotamatic Pictorial - (Figure 20) R-010-A-F Diehead Threading Assembly, ½"-2 11 - ( Figure 21) R-011 Diehead Front Plate R-012-A-F Diehead Back Plate Assembly, ½" -2" R-013-A-F Threading Chasers, ½" -2 11 R-014 Threading Chaser Spring R-020 Diehead Frame Assembly - (Figure 22) R-021 Diehead Frame Back Plate R-022 Diehead Frame Front Cover Plate R-023 Diehead Frame Rear Cover Plate R-024 Diehead Operating Scroll R-025 Diehead Operating Scroll Washer R-026 Diehead Toggle Link R-027 Diehead Toggle Arm R-028 Diehead Operating Handle R-029 Diehead Torque Pins R-030 Cut-Off Tumble Gear Assembly - (Figure 23) R-031 Cut-Off Back Plate R-032 Cut-Off Tumble Plate R-033 Cut-Off Operating Handle R-034 Cut-Off Gear and Roller Combination R-035 Cut-Off Intermediate Gear, Large R-036 Cut-Off Intermediate Gear, Small R-037 Cut-Off Bevel and Spur Gear Cluster R-038 Cut-Off Gear Pins R-040 Cut-Off Frame Assembly - (Figure 24) R-041 Cut-Off Frame R-042 Cut-Off Sliding Block R-043 Cut-Off Wheel R-044 Cut-Off Roller R-045 Cut-Off Feed Screw R-046 Cut-Off Feed Screw Knob R-047 Cut-Off Feed Screw Bevel Gear R-048 Cut-Off Wheel and Roller Pins R-049 Reamer R-050 Carriage Assembly - ( Figure 25) R-051 Carria ge Frame R-052 Carriage Slide R-053 Carriage Rack 62 APPENDIX B R-060 Spindle and Chuck Assembly - (Figure 26) R-058 Front Chuck Housing R-059 Front Chuck Scroll Plate R-061 Front Chuck Master Jaw Assembly R-062 Front Chuck Minor Jaw R-063 Rear Chuck Housing R-064 Rear Chuck Adjustment Plate R-065 Rear Chuck Scroll Plate R-066 Rear Chuck Jaw R-067 Outer Spindle R-068 Inner Spindle R-069 Spindle Gear R-070 Motor Assembly - (Figure 27) R-071 Motor Armature R-072 Motor Field R-073 Motor Brush Assembly R-074 Motor Fan R-075 Motor End Bell R-076 Motor Housing R-077 Motor Gear Case R-078 Motor Armature Pinion Gear R-079 Motor Cluster Gear R-081 Motor Final Gear R-082 Motor Spindle Pinion Gear R-083 Motor Switch Lever R-080 Cutting Oil System - (Pigure 28) R-084 Oil Sump and Tray R-085 Gear Pump Assembly R-086 Pump Output Line R-087 Flexible Hose R-088 Diehead Valve Bolt R-089 Diehead Line R-090 Frame Assembly - (Figure 29) R-091 Frame Casting R-092 Carriage Guides R-093 Chuck Brake Shoe R-094 Chuck Brake Linkage R-095 Chuck Brake Lifting Cam R-096 Chuck Operating Handle R-097 Carriage Positioning Pinion Gear and Shaft R-098 Carriage Positioning Wheel R-099 Machine Carrying Handle R-100 Rotamatic - Final Assembly - (Figu.re 30) 63 APPENDIX C ROTAMATIC STRESS AND LOAD ANALYSIS 1. R-010 Diehead 'rhreading Assembly Design Torque, T = 2000 11 # (F'ig. 5) a. Load at the mounting holes: FT~ T/1: 2000/7.00 • 286// b. Right mounting hole in tearout: S = 286/.188 x.25 = 6100 psi f.s. = 60,000/6100 = 9.7 c. . 25 = length of tearout f.s.= factor of safety 60,000= shear ultimate mild steel 2.375 = diameter 2 11 pipe Ample. Forces on chasers: FT: 2000/2.375 x 2 = 421# d. Fr Forces on chaser guides: FA: 421 x 1.63/1.25 • 550# 421 = 129# Assume FT= FR= 421# e. Force against scroll slot of chaser: f. Shear in weld between chaser guide and back plate: s a P/.24 x 1 X t = 550/.24 X = 6100 psi f.s. p - load .24 = welding constant 1.5 x.25 1 • Length of weld t • Thickness of weld 60,000 = Shear ultimate of weld = 60,000/6100 • 9.7 Ample. 64 2. R-020 a. APPENDIX C Diehead Frame Assembly Load on mounting bolt and stop pad: FA= 2000/10.50 • 191# b. Load on torque pin threads: FB = 286 x 2.00/.439 • 1300# c. Shear on back plate threads: Load/thread= 1-rf'"'rt.Ttt-___L- ~ 1300/15 = 8 7# ............................•.--.r--1!,. Assume tension load carried by 900 arc of the thread. ~ 87 X 4 ss = . 43917'x. 0 5 = 5050 psi f. s • d. = 4 O, 000 / 50 50 : . 1-00 . ~ - - - , Z . 00 - - + - 1 7. 9 Ample. Bending in the torque pin: S = Mc/I : 286 X 2.00 X .25/.00307 = 5000 psi f.s. = 60,000/5000 = 12.0 M = bendin g moment c • pin radius I= moment of inertia of pin Ample. 65 3. APPENDIX C Cut-Off Tumble Gear Assembly R-030 Design Torque = 80 11 # at 50 rpm a. Gear velocity: V b. 2.37511 = diameter of 11 2 pipe Force on gear teeth: F c. = 50 x 2. 37517" /12 = 31 fpm = 80/1.00 = 80# 1.00 11 = pitch .radius of feed screw bevel gear Gear allowable tooth stress: 90,000 600 90,000 = tension ulti3 X 600 + 31: 28,600 psi mate for 1040 heat-treated steel Gear face width: S: d. _ PaF _ b - 1tsy - 24 X 80 28,800 x.095 X = .224 11 Pd F s y = diametrical pitch = load on teeth = allow. tooth stress = form factor Use standard 24 pitch, 14½0 involute, SAE 1040 heattreated spur gears with ¼" face. 4. Cut-Off Frame Assembly R-040 a. Load on the feed screw: M F :: f r ( X feed screw thread is COS d-- cos L.. + tan<,( ) 2 80 = • 21 7(•09 . 8X 6 6.99 + . 154) : 1450# ½ NC-13 (Fornru.la for sharp t hreaded screw) M = turning moment f = coef. of friction «=angle of pitch '8 = an gle between faces 66 b. APPENDIX C Shear on the feed screw threads: = 75/1 Load/thread= 1450/1.5 x 13 S S = .416 = Root dia. screw .077 = Thickness of _____thread at root 75 .41611'x .077 - 745 psi c. Frame in tension: FT - 1450/2 X . 562 = 1290 psi f.s. = 40,000/1290 = 31 d. A1u,p .56Z Ample. 40,000 = tension ultimate aluminum Bevel gear face width: b _ P 0F _ --rtsy - 12 x 80 1T"x 28800'x.095 - .448 11 (Velocity, forces, and allowable tooth stresses same for bevel gear as for spur gears in tumble gear assembly.) Use standard 12 pitch, 14½0 involute, SAE 1040 heattreated bevel gears with 5/8" face. 5. R-050 a. Carriage Assembly Diehead supports in bending: s = Mc/I = t fOO# .73 500 X 5.30 x.375 2.75 X • 753 /12 ~10.= = 10,300 psi F,,. Satisfactory. f.s. = 40,000/10,300 = 3.88 b. Load on carriage guides: FA= 500 x 5.30/10.00 = 266# Note: ~ For derivation of 500# load see 9-e Page 71 67 6. R-060 Spindle and Chuck Assembly Design Torque a. APPENDIX'C = 2000 "# at 50 rpm Load on front chuck jaws: ,--+--,=~"""'-~~........i.__ 2000# /./68 Fo1- F = 2000/1.188 x tan 10° ,2''f}e = 9520# Load/tooth= 9520/6 = 1590# 6 active teeth per jaw b. Shear in scroll plate teeth: = 1590/1.00 x.10 Ss = 15,900 psi f.s. = 4·5 , 000/15, 900 = c. - 1.00 width of chuck jaw .10 = thickness of jaw tooth 45,000 = shear ul timat)e cast 2.83 Satisfactory .. steel Shear on aluminum shear pins: 2000 s8 = 2.38 x 3 = 10,100 psi . 094 2 11"' f.s. = 20,000/10,100 = 1.98 .188 = dia. of shear pins 2.38 = outside radius of outer spindle Pins will shear at 4000 11 # torque load on pipe. d. Spindle gear velocity~ V : 50 x 9. 60 '(t'/12 = 125 fpm e. Force on spindle gear teeth: F = 2000/4.800 = 417 # 9.60 = pitch dia. spindle gear 68 f. Spindle gear tooth allowable stress: S g. APPENDIX C = 45,000 4 X 600 9300 . 600 + 125: psi Spindle gear face width: 10 X 417 , 11 b : 17' X 9300 x.117 : 1. 22 Use standard 10 ~itch, 14½0 involute, cast steel, spur gear with 1 4 11 face. h. Load on spindle bearings: Fp = 11.62/13.50 x 417 = 360# : 417 - 360 = 57# ---11.631 /.88 New Departure extra-light fi' -1-rNIFF bearings N-OL24 used because of spindle size have rating of 11, 700# for 50 rpm. i. Stress in outer spindle from combined torsion and bending: MB : 360 x 1.88 : 675 11 # Shear Diagram • MT - 2000 11 # (design) VMB2 + MT2 s = .8 1TD 0 4 - Di 4 ( 16 D0 ) v6752 :t 20002 = .s(1T4.754 - 4.oo4) 16 X 4.75 f.s. = 45,000/1160 = 39 MB = max. bending moment MT = max. torsional moment Do• outside dia. spindle Di = inside dia. spindle (. 8 factor for keyway) = 1160 psi Ample. 69 7. R-070 Motor Assembly Design Torque a. APPENDIX C = 250tr# at 400 rpm HP output at design conditions: : 2 ft X 2 50 X 400 = z• 08 HP = 21TMn 33,000 hp 33,000 b. Spur pinion gear velocity: V : 400 X 1. 200 ft /12 = 125 fpm c. 1.200"= pitch dia. of pinion gear Force on spur pinion gear teeth: F = 250/.600 = 417# d. Spur pinion gear allowable tooth stress: S = 90,000 4 e. X 600 600 + 125 = 18,600 psi Spur pinion gear face width: b : 10 x 417 = 1. 07" 1tx 18,600 x.067 Use standard 10 ~itch, 14½0 involute, SAE 1045 steel spur gear with 1 4 11 face. f. Cluster small gear velocity: V: 400 x 4.25 x 1.001t/12 = 535 fpm g. Force on cluster small gear teeth: F = 250/ 4.25 x .500 - 118# 4.25 = ratio of cluster gear to spur pinion gear 1.00 = dia. small gear 70 h. APPENDIX C Cluster small gear allowable tooth stress: S: 90,000 X 600 : 17,400 psi 3 600 + 535 i. Cluster small gear face width: 16 X 118 b = 'ftx 17,400 x.067 = . 515 11 Use standard 16 pitch, 14½0 involute, SAE 1045 steel, helical gear with½" face. j. Motor armature pinion gear velocity: k. 17.00 = ratio of armature to pinion gear = 2140 fpm speed 1.00 = pitch dia. armature gear Force on motor armature pinion gear teeth: V = 400 x 17.00 x l.OOft/12 F - 250/ 17.00 x .500 : 29# 1. Motor armature pinion gear allowable tooth stress: S = 90,000 3 X 600 600 + 2140 = 6580 psi m. Motor armature pinion gear face width: 20 X 29 b = 11"x 6b80 x.090 - .312 11 Use standard 20 pitch 14½0 involute, SAE 1045 steel, helical gear with 3/8fr face. 71 8. APPENDIX C R-080 Cutting Oil System No stress check made. 9. R-090 a. Frame Assembly Brake load on front chuck housing: F;. Spring Force= 80# FA: 6.50 x 80/2.10: 260# b. Friction force on brake lining: F = fN f = coef. of friction N = normal load : .5 X 260: 130# c. P d. = 130/1.75 = 74 psi Satisfactory. Bral{ing moment on spindle: M e. 1.75"2 • brake area Pressure on brake lining: = 130 x 3.75 = 488"# 3. 75 11 = front chuck radius Satisfactory. Force on carriage positioning gear teeth: F : 3.00 x 100/.60: 500# f. Carriage positioning gear face width: b : 1T"X = 1.06 10 X 500 22,500 X .067 11 Use standard 10 pitch 14½0 involute, SAE 1045 steel, spur gear with l¼" face. 72 APPENDIX D ROTAMATIC WEIGHT ANALYSIS The following weight analysis was made by calculating the I volume of each of the parts of the Rotamatic. The specific weight of the steel was assumed to be .278#/cu. in., and the specific weight of the aluminum was taken as .100#/cu. in. A summary of the weight of each of the major assemblies of the Rotamatic is as follows: AssemblX Weight # R-010 Diehead Threading Assembly 4.48 R-020 Diehead Frame Assembly 6.49 R-030 Cut-Off Tumble Gear Assembly 5.21 R-040 Cut-Off Frame Assembly 6.14 R-050 Carriage Assembly 13.60 Carriage - Total Weight 35. 72 R-060 Spindle and Chuck Assembly 69.17 R-070 Motor Assembly 40.21 R-080 Cutting Oil System 11.80 R-090 Frame Assembly 60.11 R-100 Final Assembly - Total 1Neight 217. 01 On the basis of the above calculations the nominal net weight of the Rotamatic with one threading assembly is 220: pounds. A tabular summary of the volume and weight of the detail parts is presented on pages 73 and 74. 73 APPENDIX D Part Number . R-011 R-012-F R-013-F R-014 R-010 Front Plate Back Plate Assem. 2" Chasers, 211 Chaser Spring Diehead Threading Assem. 1 1 4 4 Steel R-021 R-022 R-023 R-024 R-025 R-026 R-027 R-028 R-029 R-020 Back Plate Front Cover Plate Rear Cover Plate Operating Scroll Scroll Washer Toggle Link Toggle Arm Opera tin g Handle Torque Pin Diehead Frame Assembly 1 1 1 1 1 1 1 1 2 Alum. R-031 R-032 R-033 R-034 R-035 R-036 R-037 R-038 R-030 Back Plate Tumble Plate Operating Handle Gear & Roller Combin. Intermed. Gear, Large In termed. Gear, Small Bevel & Spur Cluster Gear Pins Cut-Off Tumble Gear As. 1 1 1 2 1 2 1 1 Alum. Steel R-041 R-042 R-043 R-044 R-045 R-046 R-047 R-048 R-049 R-040 Cut-Off Frame Sliding Block Cut-Off Wheel Cut-Off Roller Feed Screw Feed Screw Knob Feed Screw Bevel Gear Wheel and Roller Pins Reamer Cut-Off Frame Assembly 1 Alum. R-051 R-052 R-053 R-050 Carriage Frame Carriage Slide Carriage Rack Carriage Assembly Part Name .No . . Mat'rl Volume Weight Req cu.in. lbs. II "II II II Steel II ti II II II II II II II II ti 1 II 1 Steel 2 II 1 1 1 II Alum. Steel 3 II 1 II 1 Alum. Steel 2 1 II 5.14 7.64 2.62 .18 1.68 12.41 6.88 6. 45 7.00 3.04 . 50 1.35 .45 1.68 1.24 . 69 .65 1. 95 .84 .14 .38 .13 .47 13.22 2.27 .45 1.28 . 78 .81 6. 51 1.83 2.02 . 73 .05 4.48 6.49 1.32 • 63 .13 .36 .22 .23 1.81 . 51 5.21 41.25 4.33 .29 .64 .98 1.80 .91 . 21 2.01 4.13 .43 . 08 .18 .27 .18 .25 .06 . 56 6.14 47. 56 10.60 21.15 4.76 2.94 5.90 13.60 74 Part Number Part Name R-058 R-059 R-061 R-062 R-063 R-064 R-065 R-066 R-067 R-068 R-069 APPENDIX D No. 1Vlat 1 rl Volume Req cu. in. Weight lbs. Front Chuck Housing Front Scroll Plate Master Jaw Assembly Minor Jaw Rear Chuck Housing Rear Adjustment Plate Rear Scroll Plate Rear Chuck Jaw Outer Spindle Inner Spindle Spindle Gear Ball Bearings Spindle & Chuck Ass em. 1 1 1 2 1 1 1 3 1 1 1 2 10.80 6.21 1.56 1. 74 3.30 .95 1.37 1 1 2 1 1 1 1 1 1 1 1 1 1 1 R-070 Motor Armature Motor Field Brush Assembly Motor Fan Motor End Bell Mot or Housing Motor Gear Case Armature Pinion Gear Cluster Gear Final Gear Spindle Pinion Gear Motor Switch Lever Ball Bearings Motor Switch 3-prong Socket Motor Assembly - R-084 R-085 R-086 R-087 R-088 R-089 R-080 Oil Sump and Tray Gear Pump Assembly Output Line Flexible Hose Valve Bolt Diehead Line Cutting Oil System 1 1 Steel 25.40 6.77 1 Copper NeoprnE Steel Copper -.21 R-091 R-092 R-093 R-094 R-095 R-096 R-097 R-098 R-099 R-090 Frame Casting Carriage Guide Brake Shoe Brake Linkage Brake Lifting Cam Chuck Operating Handle Carr. Positioning Gear ' Carr. Positioning Wheel Carrying Handle Frame Assembly R-060 R-071 R-072 R-073 R-074 R-075 R-076 R-077 R-078 R-079 R-081 R-082 Ru083 6 1 1 1 1 2 1 1 1 1 1 1 2 Steel II II II Alum. II Steel " II II II II - - Alum. Steel II II II II • II II II II II Alum. Steel Alum. Steel II II II Alum. Steel 38.87 22.38 5.59 6.26 33.02 9.44 4.93 1.18 52.88 36.55 35. 60 29.40 - .33 14.65 10.18 9.90 8.18 69.17 5.20 19. 85 13.15 29.60 . 39 7. 46 8. 75 9.90 2.00 . 52 5.32 3.66 8.22 .11 2.08 7.34 2.06 1.39 .14 11.22 .38 .04 3.22 1.20 . 75 40.21 -- - - - 7.07 1.88 . 78 1.39 .06 .62 11.80 47.99 479. 90 5.35 19.26 .32 3.22 . 79 2.66 .45 1.62 .45 .13 7.18 2.00 14.37 ' 1.44 5.92 1.64 60.11 75 APPENDIX E ROTAMATIC COST ESTIMATE The following cost estimate was made by computin g material and labor cost for each part of the Rotamatic. :/p . 075/lb. was used for the cost of all steel parts, and $.240/lb. was used for the cost of all aluminum parts. In the quanities needed, ball bearings were estimated at m:1.00/lb. field were estimated at $ .70/lb. The motor armature and Other electrical items were estimated on the basis of their present cost. All labor was estimated at $4.50/hour which included overhead. was estimated on the basis of jig set ups. Labor time $100,000 has been estimated as the tooling cost, and prorated over 5000 units. The selling cost was calculated by multiplying the manufacturing cost by three. The cost of each of the major assemblies is as follows: R-010 R-020 R-030 R-040 R-050 R-060 R-070 R-080 R-090 R-100 Diehead Threadin g Assembly (6) $ 30.38 Diehead Frame Assembly 10.66 10. 53 Cut-Off Tumble Gear Assembly Cut-Off Frame Assembly 8-. 67 Carria ge Assembly 6.33 Spindle and Chuck Assembly 32.21 Motor Assembly 32.22 Cutting Oil System 10.84 Frame Assembly 31.92 Assembly 80 min. 6. 75 Finishin g 6. 75 80 min. Packing 20 min. 1.50 Tooling Cost 20.00 Tot a l Manufact u rin g Cost $208. 76 Total Sellin g Cost $625.00 A tabular summary of the cost of the detail parts of the Rotamatic is presente d on pa ges 76, 77, 78 and . 79. Back Plate Tumble Plate Operating Handle Gear & Roller Combin. In termed. Gear, Lar ge Intermed. Gear, Small Bevel & Spur Cluster Gear Pins Assembly • Cut-Off Tumble Gear Assem R-031 R-032 R-033 R-034 R-035 R-036 R-037 R-038 -·- R-030 1 1 1 2 1 2 1 1 Steel 1 1 1 1 1 2 " II ti II II II Alum. Steel II II II II II 1.32 ~ 63 .13 , ~36 .22 .23 1.81 . 51 . 608 .317 .047 .010 .027 .017 .017 .135 .038 .911 II 1 R-020 .296 .165 .156 .146 .063 .011 .029 .010 .035 Alum. 1.24 . 69 .65 1.95 .84 .14 ~38 .13 .47 II 1 1 Back P:hate Front Cover Plate Rear Cover Plate Operating Scroll Scroll Washer 'l'oggle Link Toggle Arm Operating Handle Torque Pin Assembly Diehead Frame Assembly .126 .152 .055 .004 R-021 R-022 R-023 R-024 R-025 R-026 R-027 R-028 R-029 " " 1.68 2.02 . 73 .05 . Mat I rl Weight Cost $ # 7337 , tr Steel No. Req Mat 1 rl 1 1 4 4 Part Name R-011 Front Plate R-012-F Back Plate Assem., 2" R-013-F Chaser 2" R-014 Chaser Spring Assembly R-010 Diehead Threading Assem. Part Number 22 8 13 25 10 5 8 30 10 35 8 8 33 10 4 8 8 8 8 2 2 8 12 40 Labor Time min. 2. 250 • 750 .600 1. 650 .600 . 975 1.875 . 750 ~375 9. 625 2. 625 .600 .600 2.475 . 750 .300 .600 . 600 . 600 .600 9. 750 2.567 . 797 .610 1. 677 . 617 1.092 2.010 . 788 .375 10. 533 I 2.921 . 765 . 756 2,621 ,813 .311 629 .610 .635 .600 10.661 1.026 3.152 .655 .154 .150 5.062 $ $ .900 3.000 .600 .150 .150 4. 725 Total Cost Labor Cost tx:I :>< H 8 f:Ij 1-,:j l'rj :x:,. ~ O') Carriage Frame Carriage Slide Carriage Rack Assembly Carriage Assembly Front Chuck Housing Front Scroll Plate Master Jaw Assembly Minor Jaw Rear Chuck Housing Rear Adjustment ' Plate Rear Scroll Plate Rear Chuck Jaw Outer Spindle Inner Spindle Spindle Gear Ball Bearing Assembly Spindle & Chuck Assem. R-051 R-052 R-053 R-058 R-059 R-061 R-062 R-063 R-064 R-065 R-066 R-067 R-068 R-069 R-060 R-050 R-040 Cut-Off Frame Sliding Block Cut-Off Wheel Cut-Off Roller Feed Screw Feed Screw Knob Feed Screw Bevel Gear Wheel and Roller Pins Reamer Assembly Cut-Off Frame Assembly Part Name R-041 R-042 R-043 R-044 R-045 R-046 R-047 R-048 R-049 Part Number 1 1 1 2 1 1 1 3 1 1 1 2 1 2 1 1 3 1 1 1 2 1 1 1 II If II If If Steel If Alum. If ti ti Steel II Alum. Steel II II Alum. Steel II II Steel " Alum. No. Req Mat' rl 10.80 6.21 1. 56 1.74 3.30 . ~ 95 1.37 .33 14~65 10~18 9.90 8.18 4. 76 2~94 5. 90 13.390 .810 .465 .117 .131 . 792 .228 ·,· .103 ~025 1~100 •. 764 . 675 8.180 1 . .804 1.142 .220 .442 .421 .198 .103 .006 .014 .020 .014 .019 .005 .042 $ # 4.13 .43 .08 .18 ..27 .18 .25 .06 . 51 Mat'rl Cost Weight 2.250 1.275 1. 500 • 1.875 1. 275 .600 1.200 1.875 2.250 2~ 250 1.875 . 750 18.975 10 1. 725 1.150 . 750 .900 4. 525 3.060 1. 740 1.617 • 2. 006 2.067 .828 1.303 1.900 3.350 3.014 2. 550 8.180 . 750 32.365 2.867 1. 370 1.192 .900 6.329 3.348 .853 .381 . 564 . 470 .464 . 694 .230 . 642 1.125 8. 671 $ $ 3.150 • 750 .375 .450 . 450 . 450 . 675 .225 .600 1.125 8.250 Total Cost Labor Cost 30 17 20 25 17 8 16 25 30 30 25 23 14 10 12 6 6 9 3 8 15 6 42 10 5 Labor Time min. . t_:rj >< H 8 l,:j :t> "'tJ 1-rJ -..J -..J Oil Sump and Tray Gear Pump Assembly Output Line Flexible Hose Valve Bolt Diehead Line Assembly R-084 R-085 R-086 R-087 R-088 R-089 R-070 Motor Armature Motor Field Brush Assembly Motor Fan Motor End Bell Motor Housing Motor Gear Case Armature Pinion Gear Cluster Gear Final Gear Spindle Pinion Gear Motor Switch Lever Ball Bearin gs Motor Switch 3-prong Socket Assembly Motor Assembly Part Name R-071 R-072 R-073 R-074 R-075 R-076 R-077 R-078 R-079 R-081 R-082 R-083 Part Number 1 1 1 1 1 1 1 1 6 1 1 2 1 1 1 1 1 1 1 1 1 Copp. Neop. Steel Copp. II Steel - - II II II II II II II II Steel Alum. No. Rec; Mat'rl 7.07 1.88 . 78 1.39 .06 . 62 2.413 . 530 .142 .390 1.025 .016 .310 23.613 6.120 6.920 1.400 .125 .400 . 274 . 617 .008 .156 .154 :029 .010 3.220 2.900 1.190 $ # 8.75 9.90 2.00 ~ 56 5.32 3.66 8.22 .11 2.08 2~06 ~ 38 ~04 3.22 1.20 . 75 Mat'rl Cost Weight 8 15 4 4 10 45 13 23 15 10 22 12 10 2 8 8 --6 --- Labor Time min. 8.425 .975 3.375 .300 . 750 .300 . 600 1.125 1.72.5 8.600 .600 .600 1.125 . 750 1: 650 .900 . 750 .150 -. 450 - - $ Labor Cost 1. 505 3. 517 .690 1.775 .316 .910 1.125 10. 838 6.120 6.920 1.400 . 575 1.000 .874 1. 742 • 758 1.806 1.054 . 779 .160 3.220 2.900 1.190 1. 725 32.213 $ Total Cost t_:rj ><: H t:J zt.x.! t-rj "t1 :i:,, -.;J co R-090 R-091 R-092 R-093 R-094 R-095 R-096 R-097 R-098 R-099 Part Number ' Frame Castin g Carria ge Guide Brake Shoe Brake Linkage Brake Liftin g Cam Chuck Operating Handle Carr. Positioning Gear. Carr. Positionin g Wheel Carrying Handle Assembly Frame Assembly Part Name - 2 1 2 1 1 1 1 1 1 Alum. Steel II II II Alum. Steel Alum. Steel No. Req Mat'rl $ 11. 518 .401 .077 .059 .034 .010 .150 .346 .123 # 47.99 5.35 .32 . 79 .45 .13 2.00 1.44 1.64 12.718 Mat'rl Cost Weight ,. 125 25 16 12 8 8 17 17 8 20 Labor Time min. 9.375 1.875 1.200 .900 . 600 . 600 1.275 1.275 . 600 1·. 500 l~.200 $ Labor Cost 20.893 2.276 1.277 .959 .634 .610 1.425 1.621 • 723 1.500 31.918 $ Total Cost .. tr:J >< H s t:r:l 1-tj 1-tj :i:,. (D -;J 80 APPENDIX F ROTAMATIC MARKET ES'rIMATE The present market for portable pipe threading machines consists primarily of heating and plumbing shops for construction and repair work, and to a lesser extent of institutions and factories for repair work. machines tends to be inelastic. Demand for these It is influenced largely by the business cycle, and in particular by the building and construction cycle. At the present time the demand for portable machines appears high, although lessening. The estimated total annual production of portable pipe threading machines in the United States, as discussed on pages 13 and 14 is approximately 5000 units. The average life of these machines was estimated to be approximately six years. The market for the Rotamatic will come from the following sources: (1) the new market consisting of new plumbers entering the trade, of present plumbers who are not using portable pipe threading machines, and of institutions and factories not now using this type equipment for repairs; and (2) the replacement market consisting of plumbing shops, institutions, and factories whose machines have worn out. 'l'he nuinber of annual sales of the Rotamatic will depend upon the reputation of the manufacturer who produces the machine; his plant, distribution, and advertising 81 APPENDIX F facilities; the business cycle, and the state of competition. A market advantage will be gained from the patenting of the automatic chucking device, the threading mechanism, and the cut-off and reaming mechanism. It appears reasonable to assume a first year production of 1000 units. Since the cost of tooling has be prorated over 5000 units, a five year production at this rate will be required to amortize this cost. Assuming the average life of the Rotamatic to ·be approximately six years, if its production is scheduled on a five year program, there will be a replacement market ready at the end of that time for a redesigned, improved version of the machine. 82 APPENDIX G ROTAMATIC SALES AND ADVERTISING FEATURES Distribution of the Rotamatic will be through the usual portable pipe threading machine channels, from factory to jobber, to consumer. Advertising and sales literature will be needed at both the jobber and consumer level. Jobber advertising will need to consist of an outline of increased profits and new sales opportunities offered by the Rotamatic, and of instructions for its sales display. Profits and sales opportunities can be dramatized on standard 8½" x 11" single sheets, or 17 11 x 11 11 folded sheets so the factory salesman can conveniently carry them, and the jobber conveniently file them. This publicity will show by printed and pictorial means the difference and superiority of the Rotamatic. Such well recognized slogans as "Newest Designtt and "The M.ost For Your Money", or special slogans like ttLet The Rotamatic Turn Profits Your Way" can be used satisfactorily in this form of jobber advertising. Instructions for sales display of the Rotamatic will include directions for window and interior displays, and for store demonstration of the machine. A counter card to setup behind or beside the machine bearing the name, Rotamatic, the trademark of the manufacturer, and an eye-catching legend such as "Power+ Precision= Perfect Performance," can be suitable for a wide variety of displays. A length of pipe can be 83 APPENDIX G furnished the jobber to aid him in fully demonstrating the operation of the Rotamatic. The factory salesman can be coached on details of lighting and layout to be able to give helpful suggestions and advice to fit each jobber's special display problems. Consumer advertising will need to be written for two major classes of consumers, (1) small shops, and (2) large contracting shops, institutions, and factories. Small shop advertising will stress the convenience, the flexibility, and the appearance of the Rotamatic. Half-tone cuts of the machine and of the detail parts, as well as the operation sequence will need be shown. A tabular operation time chart, over-all specifications, and the price of the machine should be included. Large shop, institution, and factory advertising will be an extension of the small shop advertising, and will contain more comphrensive machine time and cost charts of interest to the management group who estimate jobs and purchase equipment. These charts will present in tabular and graph form precise information showing how the Rotamatic will change estimations of job time, and lower costs. A factory salesman with an under- standing of en gineering and plumbing-job estimating should be available to further promote the sale of the Rotamatic to interested consumers of this class by personal calls. 84 APPENDIX G All Rotamatic sales publicity should b e written so as to be useful for other classes as well as the specific one for which it is intended. The advertising should be sufficiently dif- ferent from other portable pipe threadin g machine literature to make it stand out in the minds of jobbers and consumers alike. The color and layout of the copy, and the size and fold of the paper are important to make the advertisin g carry punch. Black and red ink on grey paper might be used to harmonize with the actual color of the machine. The following sales points of the Rotamatic should be included in all advertising copy: ( 1) The Name--as being sug"~esti ve of a modern, fast, precise machine, and different from existing names. ( 2) The Advanced Design--emphasizing speed and ease of operation. (3) The Improved, Clean-Line Appearance. (4) The New Mechanical Features--the simplified diehead design, the improved reamer location, the new power cut-off mechanism, the fully automatic chuck, and the flexible carriage arrangement. For continuing factory-consumer advertising, a file system could be kept for purchasers of the Rotamatic, and convenient operating suggestions and announcements of new designs could be mailed to them periodically. 85 APPENDIX H ROTAW.LATIC MAINTENANCE AND SERVICE REQUIREMENTS Lubrication which the Rotamatic requires for ordinary service which can be done by the owner is as follows: (1) Cut-off mechanism--oil gears once a month (2) Spindle gear--grease with heavy grease once a month (3) Front and rear chuck scroll plates and jaws--oil with SAE 10 or 20W oil once a month (4) Carriage guides--oil with SAE 10 or 20W oil once daily (5) Spindle bearings--oil with SAE 10 or 20W oil once daily Miner adjustments which the Rotamatic requires which can be done by the owner are as follows: (1) Threading mechanism--sharpen chasers when dull, and adjust threading assemblies for exact thread diameter. (2) Cut-off mechanism--replace cut-off wheel when dull (3) Reamer--sharpen when dull (4) Automatic chucking device--adjust rear chuck scroll plate for front jaw wear, adjust brake spring for brake force, and adjust brake linkage for wear of brake lining. Major servicing such as motor burn-out, carriage guide wear, chuck breakage, threading or cut-off mechanism breakage will • require factory or factory supervised servicing. 796 - - 580 37-50 - - -- 520 25-36 ½-2 15 6 10 42 427 16-30 ½-2 --·~ 5 20 0 695 60-90 1 11 2- 4 450 40 20¼ 28 Oster #531-A 9 27 5 15 698 30-50 ½-2 525 42 21 24½ #582 0 19 0 8 545 40-54 ½-2 Indicates lack of data. -6 - (All data from company sources.) 10 - 15 tl.400 trans. 40-335 22 550 - ½-2 850 371 185 .1. 2- 2 . 45 31 47 36 14 20 Toledo 999 .Hi-Spd 33 12 18 3A Q,ui 1 da * Machine will not cut-off, times are for 1-¼" pipe. Operating time Chuckin g ComThreadi ng 1Plete Reaming JperaCutting-off ltion 100 (2 11 pipe in seconds) Price $ with 6 dieheads It rans. Spindle Speed ~0,35 ~ 70 rpm ½-2 - Weight - # ½-2 265 4g5 - Standard Range of Pipe 46 19½ 18 36 18 13½ - - Size - - II Length Width Height 375 #502 Am.T'l Beaver Specification & Die .R-E-H .Mod. A Mod. B z {/) Cf.l l?=.l ~ H~ 0 t:l p:1 :i> g:1 !Z! C,i ~ 8!2.:t:nEi1 ► tu gg~ ~ o f-3 t~j 'vO I'd f-3 HH :i> ~~ t:JJ t--9 f-30 ~· H ::0 trj 0 1-tj 11:J {/) :i> H X H l?=.l !Z! t:l '1::J 1-tj CP ()) 36. BEAVER MODEL-A 3 7. QUIJADA No. 3A 38. BEAVER MooEL-B 39. TOLE DO HIGH SPEED 40. TOLEDO No. 999 41. R E D-E- HAUL 42. OSTER No. 582 43. 0 ST E\R !-----=:;;;;.;;.;~~ No. 502 44. OSTER No. 531A 87 APPENDIX J PIPE THREADING MACHINE PATENTS Patents of interest in the design of pipe threading machines: (1) Patent No. 1,199,917 - H. W. Oster, 1916, portable tool turning machine. (2) Patent No. 1,789,412 - H. W. Oster, 1931, variable speed device. (3) Patent No. 1,814,675 - F. W. Erikson, 1931, power cutter for round objects using two rotating motors and two routers. (4) Patent No. 1,883,728 - J. F. Haas, 1932, portable electric-powered self-opening diehead. ( 5) Patent No. 1,871,732 - H. lVI. Olmstead, 1932, adapter for using electric drill for threading. (6) Patent No. 2,195,578 - A. M. Hexdall, 1940, hand tool which rotates die to thread but rotates pipe to cut-off and ream. Patents issued and applied for on present portable pipe threading machines: (1) Beaver Pipe Tools, Inc. Patents issued: perforated removable chip tray; ball-bearing, self-centering wheel and roller cut-off assembly. (2) The Oster Manufacturing Co. Patent applied for: "Spinfast" wrenchless chuck. ( 3) Quijada •rool Co., Model 3A. Patents applied for on entire 88 APPENDIX K SUGGESTIONS FOR FUTURE PORTABLE PIPE THREADING MACHINE DESIGN Future design of portable pipe threading machines can be divided into three classifications: chine develop~ent, (2) (3) (1) Rotary-tool ma- Rotary-pipe machine development, Thread rolling machine development. The development of a rotary-tool pipe threading machine would progress from the preliminary design studies conducted as a part of this thesis and discussed on pages 30 to 33. A semi- automatic turret machine haiing ·carbide tipped tools and enough power to thread in one half to one quarter the present time could conceivably be economical in large contracting shops. On the other hand, light, power-driven hand tools, if cheap and rugged enough, could compete with present day hand tools. The design of rotary-pipe machines has many aspects which the designer believes need further development. ing systems are still in their infancy. sible to develop Automatic chuck- It should be pos- an automatic chucking system which would not be much more heavy or complex than a present-day universal chuck. A further step in the development of opening die- heads is to mount the reamer so that pressure upon it opens the chasers as is now done on production pipe threading machines. With modifications and simplification, this system could be adapted to portable machines. By the use of carbide APPENDIX K 89 tipped chasers and the installation of more powerful,lighter motors present operating speeds can be halved. The cut-off assembly mignt be power-driven by a lead screw. So~e inves- tigation was done on allowing the cut-off tool to toggle into the pipe using the pipe torque to feed it. This method of power feeding the cut-off tool which would eliminate all gear drives would be V10 rthy of further investigation. With the growing availability of light, high-strength alloys a portable pipe threading machine weighing around 100 pounds as fast and durable as any today should soon be commercially practical. A portable pipe thread-rolling machine might be practical as a very rapid method of threading. A mandrel would have to be inserted inside the pipe to prevent crushing. The develop- ment of such a threading machine would involve extensive experimentation. The goal of all future research and development of portable pipe threading machines will be towards more s~eed, precision, and flexibility, and less cost, weight, and complexity. 90 APPENDIX L BIBLIOGRAPHY 1. Statistical Abstract of the United States, U.S. Department of Commerce, Number 67, 1946, pp. 811-813 2. Census of U.S. Manufacturers 1939, U.S. Department of Commerce, Vol II, part II, pp. 433 3. M. E. Merchant, "Basic Mechanics of Metal Cutting Process," Journal of Applied Mechanics, Sept. 194t.1:, pp A-168 to A-175 4. M. E. Merchant and N. Zlatin 11 New Methods of Analysis of Machining Processes," Experimental Stress Analysis, Vol. III, No. 2, 1946 5. S. P. Alim, 11 Machinabili ty" of California, 1948 6. Manual of Cutting of Metals, prepared by ASME Committee of Metal Cutting Data, 1939 7. Screw Thread Cutting 8. H. R. Glauser, "Metal Powder Parts Replace Those Produced by Other Methods~ Material & Methods, November 1948 9. W. H. Clapp and D. s. Clark, Engineering Materials and Processes, International Textbook Company, Scranton, 1948 10. R. J. Roark, Formulas for Stress and Strain, McGraw-Hill Book Company, New York, 1943 11. c. A. Norman, E.S. Ault, I. F. Zarobsky, Fundamentals of Machine Design, The Macmillan Company, New York, 1938 12. Ben Nash, Developing Marketable Products and Their Packagings, McGraw-Hill Book Company, New York 1945 Engineering Thesis, University Manual, The Geometric Tool Co., 1946