The Iron Age 1944-11-02: Vol 154 Iss 18

VAN DEVENTER and Editorial Director AUR General Manager Editorial and Advertising Offices 100 East 42nd St., New York 17, Johnson, Market Research Production Manager. Baur, and Layout Regional Business Managers New York New ork East 42nd St. ROBERT BLAIR Cleveland Guardian HERMA Philadelphia Chilton PEIRCE LEWIS Bidg. Detroit Woodward Ave. RAYMOND KAY Los Ang 100 East 42nd Pittsburgh Park Bidg. HOTTENSTEIN ord eles 2420 Cheremoya Ave. Owned Published CHILTON COMPANY (incorporated) Executive Offices and Sts. Philadelphia 39, Pa., U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President HILDRETH GEORGE GRIFFITHS TERHUNE BAU Vice-President Vice-President Vice-President Vice-President Vice-President Treasurer JOHN BLAIR MOFFETT, CHASE DUFFY HARRY THOMAS KANE FAHRENDORF CHAR ° LES HEALE Member, Audit Bureau Circulations indexed the Industrial Arts Index. Pub- lished every Thursday. North America, Sout Subscription Price America and $8; Foreign, $15 year. Single Copy, Vol. 154, No. AGE November 1944 Editorial Mists and Myths Technical Articles Appraisal Precision Thread Rolling Practice Plastic Coatings for Surface Inspection Projected Plastic Measuring and Designating Surface Finish Two Million Volt X-Ray Tube Tank Production the Soviet East Shot Peening New Equipment Features News Front Assembly Line Washington West Coast Personals and Obituaries Fatigue Cracks Dear Editor This Industrial Week News Industry News and Markets Civilian Output Publicity Attacked Freight Car Inquiries Lagging Machine Tool Builders’ Problems Bethlehem Modernizes Shipyards Highway Postwar Construction Controls Copper Lifted Truck Production Off Machine Tool Market Developments Non-Ferrous Metals News and Prices Iron and Steel Scrap News and Prices Comparison Prices Week and Year Finished Iron and Steel, Steel Prices Warehouse, Semi-Finished, Tool Steel Prices Steel Pipe, Tubing, Wire Products, Prices Pig Iron and Coke Prices Stainless Steel and Ferroalloy Prices Index Advertisers 144 146-147 148-149 150 152 154-156 158-159 160-161 162-163 241 Member, Associated Business Papers 130 ° ° | STEEL every kind delivered QUICKLY from STOCK The Ryerson organization can rise emer- gency—move heaven and earth when called upon the impossible! But it’s day-in, day-out dependability, taking difficult assign- ments stride—that Ryerson Steel-Service stands out. ago the Ohio plant one best known manufacturers was faced with cer- tain shut-down four hundred inch bars cold rolled could not obtained overnight. The order reached Ryerson plant 4:45 the afternoon; was delivered the next morning. fanfare; just job done, and Ryerson did it. Ryerson gets these calls because Ryerson comes through—not once, now and then, but with regularity. Ryerson stocks, personnel and facilities make jobs like that look even, though not. That's the big difference. For all your steel requirements—simple tough —call Ryerson. The nearest the eleven well- stocked plants can serve you your advantage. Joseph Ryerson Son, Inc., Steel-Service Plants: Chicago, Milwaukee, Detroit, St. Cincinnati, Cleveland, Pittsburgh, Philadelphia, Buffalo, New York, Boston. ‘ | | | | | j | | | | | | | | | | | ESTABLISHED 1855 Nov. 1944 VAN DEVENTER President and Editorial Director BAUR Vice-President and General Manager ° fo] ° DIX Manager, Reader Service ° ° Editorial Staff Technical Editor ........ OLIVER Commercial Editor, CAMPBELL ° Associate Editors WINTERS ALBIN JOHN ANTHONY JACK HIGHT BARMASEL Editorial Assistants SCHIEN WILLIAMS VAN CAMP MUNZER O'CONNOR MILLER Regional News and Technical Editors LLOYD Pittsburgh 428 Park Bldg. POST Chicago 1134 Otis MOFFETT BROWNE HARDY National Press LLOYD Cleveland 1016 Guardian BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 1385 Market St. Editorial Correspondents ROBERT Cincinnati DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS St. Louis JAMES DOUGLAS Seattle Scotch Mists and Myths (Cabled from Glasgow) COTLAND has come the hard way,-and its industries show the earmarks the struggle highly developed sense prac- ticality and also the Scottish characteristic making the way fit the means. For where else the world would you find men able launch 700-ft. ships endwise river not much more than 200 ft. wide. Many Scottish shipbuilder steelmaster went forth technical college with bag porridge meal and sack kippers his total assets supplemented only his scholarship. And many them, knighted for accomplishment and not for birth, are today addressed Sir John Lord So-and-So. True democracy recognizes the aristocracy accomplishment. The same sense practicality and common sense has permeated the ranks labor the Scottish and also the English steel industry. There almost possibility the occurrence strikes, have been told both management and labor. The procedure handling grievances case individual group believes some working condi- tion should altered has been worked out elaborate detail and acceptable both parties. The first contact made with the foreman. cannot settle it, the case goes the works manager. Should agreement reached that level, impartial committee appointed, made two repre- sentatives for management and two from labor. Failing arrive decision here, which seldom occurs, the problem put before the plant labor relations head whose job try see that goes farther. But should have to, there are yet several more steps stages through before strike can considered. These steps terminate the submission the case the national management and labor authori- ties. Even then 20-day notification intention strike has filed, whereupon the Ministry Labor steps and sees that does not stop there. Over here there running biased labor relations board disgruntled employee with consequent punitive action against the employer. Nor, while the process takes considerable time goes the whole road, there the allowance retroactive wages except prior agreement. Labor unionism British steel grown up. shop steward who had not served least years plant would not considered the workers capable representing them. And when management and labor come grips with dispute, they gentlemen who respect each other and not sidewalk gangsters who hurl abuse and brickbats. can learn lot from the Scotch. | | | | | j 3 | | } | | | | | | } | 4 | q 4 | | | | | | | | q | | : | | | } | { 46—THE IRON AGE, INLAND PILIN Inland service includes furnish- ing highest quality steel sheet piling, and engineering coopera- tion design, fabrication, and field erection. Bars Floor Plate Piling Plates Rail Reinforcing Bars Sheets Strip Structurals Tin Plate Track Accessories INLAND STEEL CO. Dearborn Street Chicago Sales Offices: Cincinnati Detroit Kansas Milwaukee New York St. St. Paul November 1944 soon 51,0 out unit poun q | News October 31, 1944 General Motors plans produce about half million cars upon reconversion will require its ordering 800,000 tons steel and approximately 125,000 tons iron soon gets the go-ahead signal. Evidently GM's initial plans not include the use aluminum either for motor blocks for sheet metal sections. One the problems facing that many Fisher Division presses have been sold, leased loaned for the war period that the company concerned over the availability stamping facilities the event sudden permission mobile The development new synthetic coatings for metals and the improvement use prior 1939 will make available during the postwar period many plastic terials improve metal surfaces, cut finish costs and increase the salability market value metal products. These materials include the alkyd resins, resins, acrylic resins and phenolic resins. There are present open inquiries for only 3450 railroad cars for domestic roads, and Army requirements have been trimmed from 26,260, originally schedule for 1945, 10,470. Meanwhile: Foreign car purchases, except for those which the Army bogging down short the order stage. France, India, and South American nations all anxious place car orders, but none has actually been effected. new synthetic resin has been perfected Monsanto Chemical Co. When used low-pressure lamination process, the company claims that this resin but eliminate size restrictive factor postwar plastics. 400-passenger airplane, the largest ever contemplated, the mockup the plant, and will that company's major postwar effort. will made the new high-strength aluminum alloys and considerable quantities unusual feature the six large radial motors, driving propellers. such will resemble some the aircraft future frequently portrayed popular magazines, and likely civil the Consolidated C-99 transport airplane, which has been announced having driving pusher propellers. The traveling salesman back the road again, selling surplus war material Westinghouse has put corps salesmen the field, calling manufacturers jobbers, with lists materials declared surplus because changes contracts. The now holds within this country 300,382 prisoners war; 248,205 Germans; Italians, and 1143 Japanese. one day fighting France, two-thirds German Panzer force was out damaged bazooka teams and aircraft rockets. some cases rockets have blasted through in. armor plate. Rockets themselves not penetrate armor, punch hole through the plate terrific concentrated and directed blast effect throws hot fragments steel through the other side. Lend-lease steel will almost negligible factor steel distribution the first quarter 1945. For the fourth quarter, Great Britain, which has taken the bulk steel shipments, has reduced its ingot and semi-finished requirements. Cutting fluoroscopic sensitivity from per cent has made possible the use fluoroscopy detecting small flaws. Pacific Coast foundrymen are attempting standardize materials and for the industry there. This year's preliminary survey covers the character sand iff use and under development, both Eastern and Western. Findings show that the green Sand drying method preferred over skin drying oven drying. One the situations requiring standardization the lack uniformity measurement employed members. Units used range from tons through quarts and parts percentages. | Appraisal Precision Thread Rolling recent years there has been marked swing toward the use the rolled thread the aircraft industry place the ground thread for high precision work. this and succeeding articles attempt made appraise all the factors bearing the problem rolling thread high strength alloy steel with hardnesses ranging Rockwell and with tolerances corresponding and fits since felt that this tech- nique will applied more widely postwar production. the first part, general principles are discussed and the characteristics both straight and cylindrical die machines described. HREAD rolling not new art. Patents rolled thread- ing machines date back 1838 the United States and London there machine the South Kens- ington Museum dated 1851. Threads have been rolled this country for over years. The story told that the idea using flat die with grooves cut the helix angle the thread originat- with Englishman who playfully rolled bolt over flat piece soap during noon hour recess and, see- ing that the bolt threads produced straight line grooves the soap bar, conceived that possibly threads could rolled round blank simply passing between two reciprocating flat grooved dies. The process rolling thread can readily demonstrated simply taking pencil and rolling between the palms the hand. actual prac- tice, the blank approximately the pitch diameter the finished bolt thread and the stock cold rolled out the roots and into the crests. the conventional thread roller employing flat dies, one mounted stationary and the other reciprocated through crank and connecting rod. re- cent models, refinements have been introduced make these machines suitable for precision work. Within the last year two, two types machines employing circular dies rather than straight dies with reciprocating motion, have appeared the market primarily meet the high precision demands the aircraft industry. Basically, however, these circular die machines are not new. 48—THE IRON AGE, November More than years ago, machine was built which the bolt thread was rolled between internal rig die and external threading die. was never pushed commercially, however. the Continent, precision threads have been rolled circular die ma- chines, particularly Germany. The British have been using thread roll- ing equipment German origin (the “Peewee”) aircraft threads since the start the war. But whether the action one involving straight dies dies, the process basical- one cold forming metal although some compare the work done cir- cular dies with that spinning metal and flat dies extruding it. While the process thread rolling has been applied for many years the manufacture commercial screws and bolts that are sold the keg, many production men doubted that the process would satisfactory for machine bolts automotive en- gine and aircraft bolts and studs. To- day, however, threads are being rolled successfully high strength alloy steel heat treated hardness the average range 28-32 Rockwell and occasionally high Rockwell group aircraft bolts and studs. Fur- thermore, these threads are being rolled Class and Class fit toler- ances and occasionally Class fit tolerances. Tracing the history rolling pre- cision threads high strength hard materials, the first application was tool steel micrometer spindles. The Reed micrometer spindle has been produced with rolled thread for al- most years and still produc- tion. The next application was high speed steel taps. This job was pio- neered about years ago the Carpenter Tap Die Co. Provi- dence (later Detroit), since acquired Greenfield Tap Die Corp. The first company experiment with high strength aircraft studs this country was the Hartford Machine Screw Co., far can ascertained. When the war started, heavy de- mand was created for grinding pre- cision threads since cut threads could not obtained economically heat treated materials within the tolerances sought. Aircraft companies soon saw that would impossible get enough ground screws keep with the program despite installation hundreds thread grinders. They were therefore quite ready adopt the rolling process provided certain modifications could made the technique assure the close tolerances. The impetus for this development was given the discovery 1938 that German airplanes were being as- sembled with rolled threaded screw products. This was the occasion visit made German aircraft plants the leading aircraft engine companies the United States. was several years, however, before this company actually adopted rolled threads its production. Rolled threads not only compete with ground threads but with milled threads precision work. The most important advantage the rolled thread commercially that Class Class thread can pro- duced about times the rate achieved grinding. generally conceded that rolled thread per cent stronger than either cut ground thread because the cold forging process good grain flow produced the thread groove since the metal compressed and tends follow the contour the thread in- stead being cut through with chaser, milling cutter grinding scre Cla Eng thre dia the tur sio roc the roo cor aut rar | Practice ° ° FRANK OLIVER wheel. Fig. shows the macrostruc- tures typical rolled thread. The notch effect the root the thread reduced somewhat the compres- sion stresses which are set-up the root during rolling; also the fact that aircraft threads radius equal root place the sharp two corner form. few months ago one the large automotive plants making radial air cooled engines subcontract basis ran into epidemic cracked studs due fatigue failure the fillets. These failures were overcome sub- stituting rolled thread studs obtained assortment heat aircraft screws and Class and tolerances. Engine studs and 33, which have the first two threads 0.005 in. smaller diameter than the rest the thread can now rolled one pass. from outside source. source dried temporarily and the company was forced revert ground threads, the epidemic cracked studs immediately appeared again. This situation may amelio- rated some extent the proposed International Standard thread which will provide rounded crests and fillets, with the American National deg. thread form. Fillets rolled threads are already accepted since sharp cor- ners the crest the dies tend break down under the high rolling pressures, although corners can and are often used when specifications demand them as, for instance, the o Lum Action” photo courtesy Pratt Whitney Division, Niles-Bement-Pond The finish the thread consider- ably better and smoother. Because slippage that inherent the con- tact the blank with the dies, burnished surface produced, much finishing railroad car axles, which make the screw more less impervious fatigue failure. Slip- page due the difference diam- eter between the root and crest thread and hence the difference peripheral speed linear distance covered one revolution the blank. This slippage more pronounced circular die machines, where the same principle applies the dies well = THE IRON AGE, November > in : 1e ral ° ° ° a 34 its ete ith ; r a 3 the ow ince ~ ding machinability good, such screw machine stock where the addition sulphur lends brittleness for bettering chip fragmentation, the cold working properties are poor although threads have been successfully rolled SAE X1112 screw stock and SAE 1335 medium sulphur shell bodies. The machinability must correlated with the elastic limit, which should fair, ness. The higher the reduction area the better since this property measure the degree cold work- ability. The lower the hardness, ob- viously the greater ease deforming the material cold. the other hand, for aircraft ap- plications the material for bolts and studs selected not the basis its workability but because its functional requirements principally high strength. The alloy steels most ABOVE commonly used for this work have 2—Photomicrograph rolled high tensile strength, high hardness thread, showing how the fibers are and low reduction area. Heat- elongated the cold working action treated steels with hardness and rearranged unbroken flow lines the Rockwell 40C have been thread rolled extremely low—about 5000 6000 LEFT pieces for set single faced dies 3—Outline cut (two runs). The average range treated alloy steel stud. Rockwell and the die life This was traced from 0.000 the thread cross-section. threaded ends. This compares with million more pieces per die soft steel bolts and studs. Pitch diam Root Root 4—Tube feed and stock hopper simplify hand feeding aircraft stud blanks straight die machine. only necessary for the operator keep the tube filled with blanks, which are released one time the start the stroke. Photo courtesy Chevrolet Motor Div. General Motors. the work. particularly marked dies small diameter. Root and crest flat die, the other hand, travel the same surface speed. for this reason, incidentally, that circular dies must made smoother than flat dies. Because the better surface pro- duced the profile the thread, greater torque required drive rolled thread product. The smooth surface the rolled thread profile presents flatter bearing and conse- quently greater friction surface the material into which being screwed. Furthermore, the torque more uniform than die cut studs. The reason can found the sketch, Fig. taken from photomicrograph cut thread hard material 100 diameters. comparison, Class rolled thread appears geometrically perfect, with straight flanks. General Requirements judging the requirements material from the point view ease difficulty thread rolling, number factors must taken into Generally speaking, where 50—THE IRON AGE, November 1944 the reduction area and the hard-. the stee lent heat well mat life any forn cept the i coul folle wire rolle AIS AIS For lead have size: worl . Hardness should correlated with the ultimate strength estimating rollability. For example, SAE 6150 steel stud treated hardness Rockwell and ultimate strength 135,000 lb. per sq. in. not equiva- lent rollability SAE 3140 steel heat treated hardness Rock- well and 155,000 Ib. per sq. in. ulti- mate strength. The same average die life could not expected both cases. Although threads can rolled any material capable plastic de- formation and any thread form ex- cept square thread, aircraft work the alloy steels most frequently en- countered bolts and studs are the following: SAE 2330 8630 SAE 3135 8635 SAE 3140 8740 SAE 4027 AMS 6312 SAE 4042 AMS 6320 SAE 4640 AMS 6322A SAE 6150 AMS 6448 other applications high tensile wire (100,000 per sq. in.) has been rolled for instrument fasteners, also AISI stainless steel (18-8) and AISI 416, per cent chromium steel. For some years thread with lead error limited 0.0001 in. per in. thread has been rolled per cent tool steel the manufacture the Reed spindle screws. Commercial carbon steel taps have been thread rolled for number years, particularly the smaller sizes, but rolled taps for threading work Class and Class fits in- 6—Use eccentric sleeve rotated worm and wheel the crankpin the driving gear provides means setting the moving die forward backward and dispenses with the use filler shims under the fixed die. This optional feature Waterbury-Farrel thread rollers. variably have the thread flanks ground after rolling. aircraft work, the range thread sizes runs from %-32 thread thread studs. Some wing hinge bolts are being rolled annealed SAE the annealed state the upset and ex- truded shanks have hardness 5—Adaptation tube feed with selecting gage tray for orienting studs end for end Waterbury-Farrel No. thread roller adapted for precision work. Rockwell which raised Rock- well when heat treated, with ultimate tensile strength 175,000 lb. per sq. in. Parenthetically, should noted that the few in- stances where annealed stock rolled and later heat treated allowance must made for expansion the p.d. the thread 0.0005 in. for in. thread diameter. Many aircraft studs and bolts are plated, principally with cadmium. Thickness plate, which the order 0.0003 in. must taken into account that the p.d. the as- rolled blank must undersize. After plating the screws are heated 300 deg. for about hr. prevent hydrogen embrittlement. any type precision work, success failure depends observ- ing large amount infinitely small detail that often overlooked com- mercial work, that is, work turned out fast meet fixed market price. fact, some feel that much care must exercised the rolling precision threads that they see extension the process to, let say, automotive bolts and studs after the war. There plenty evidence the contrary indicate that the war’s end, the techniques about described should well established that roll- ing bolts Classes and fit toler- ances will considered more dif- ficult than rolling Class fits today. The chief modifications the process THE IRON AGE, November 1944—5! are the use dies extremely ac- curate thread forms and finish and the control the blank diameter within close limits. First experiments used two sets dies obtain pre- cisien thread, the first being rough- er. This follows the practice mak- ing micrometer spindle screws, still done two steps get lead accu- racy not yet approached aircraft work. the practice became better known, however, most aircraft work was and rolled final dimensions one pass. Before covering some the critical details the process, however, will necessary review the available classes thread rolling equipment now the market since the charac- teristics the machines vary widely. Several new types have appeared the past year and others are about introduced. Reciprocating Type Machines Thread rolling machines may first classified having either flat dies circular dies rolls. Recipro- types machines incorporat- ing flat dies have been existence least since 1851. this country rec- ords show that considerable thread rolling was being done 1880 such units. During this period the two main suppliers this type equip- ment were the Waterbury Farrel Foundry Machine Co. and Manville Machine Co., both Water- bury, Conn. Although many Manville thread rollers are now use, many them doing high precision work, within the last year the company has 52—THE IRON AGE, November 1944 = 2 Spring tinger center blarik LEFT 7—Close-up view the ing Machines Co. thread roller, show- ram cylinder right, hydraulic pres- sure head for the fixed die left and bridge structure de- signed dies springing apart. Stock pusher me- chanism central foreground. the start the stroke the National machine the blank held positively between the end the moving die, the feed bar, spring finger and backstop fixed the moving die. disbanded and sold all its patents and drawings the National Machinery Co., Tiffin, Ohio. For the present, the Manville machines are off the market. Basically the Waterbury and Man- ville hand feed horizontal machines used for precision work are alike that they are both geared crank driven machines having one die mounted reciprocating slide gate and the other fixed the bed the machine both and down well and out and angularity with respect the face plan the moving die. Both machines employ cam actuated starter finger pusher which literal- jams the blank between the dies the start the stroke. Although commercial work automatic feeds are far the more common, high precision work feeding these straight die machines almost invari- ably hand. For one thing, the speeds are one-third one-half the rated speed when hard materials are being rolled. Fig. shows semi- automatic type feed for recipro- cating type thread roller which the stud blanks this particular case are lifted hand from the hopper and dropped down the tube hand. merely necessary keep the tube filled with parts inasmuch trans- fer finger moves the stud over the work position the return stroke. Another type semi-automatic chute feed built into Waterbury Far- rel unit shown Fig. Such chute feeds are applicable only studs. In- clined type machines with hopper feed and the conventional type sweep pick cap screws and bolts are gen- erally not used for precision work. The few that are installed plants making aircraft screw products are turning out Class commercial screws for non-critical applications. Fig. also shows the use auxiliary stop and holding device for keeping blanks square with leading edge moving die (not shown plac this pre\ into Wat cisic for gate ting cord com slee and posi the caus die slop men sens shin vert die, Elec City type der ever atin tion: lical with feed ° ° ° ‘the . Adjust movi from corre raise aline screv the contr place). With the blank held between this stop and the pusher, tipping prevented when the blank started into the dies and the development “drunken” threads avoided, particu- larly long bolts. Another recent feature available Waterbury Farrel machines for pre- cision work adjustable pitman for driving the moving die ram gate. cuts half the time set- ting and matching the dies, ac- cording some users. The mechanism comprises sleeve the crankpin, Fig. This sleeve rotated means worm and wormwheel change the relative position the eccentric and hence the starting position the gate. Be- cause the fact that the helix the average thread and hence the die grooves roughly deg., slope 30:1, any longitudinal adjust- ment the moving die times sensitive would the insertion shims under the fixed die adjust vertically with relation the moving die, matching the pair. National Hydraulic Unit Within the last year, the National Electric Welding Machines Co. Bay City has introduced type thread roller for precision work, which the ram: motion actuated hydraulic power through cylin- der and piston connection. What even more significant from the oper- ating point view that the sta- tionary die mounted hydrau- lically actuated pressure head, Fig. with stops governing the depth in- feed. piston applies pres- 9—Front view the die ram the National hydraulic threader. The moving die may tilted from vertical plane correct thread taper raised lowered for die alinement means the taper wedge adjusting seen the end the ram. Adjusting nut controls the start position the screw blank. sure the blank rolled be- tween the dies. This the only straight type machine incorporating definite feed movement: most others rely upon slight angular setting the dies conjunction with allowance for spring the frame the ma- chine and hence the reacting pressure govern the depth penetration the dies per contact full roll. will seen later, some dies are de- signed with lead-in angle accom- plish the same effect. general, the use hydraulic power said provide cushioning effect that the hydrostatic pressure the ram can preset that the movable die will assume speed conformity with the pressure exerted the ram and with the yielding workability the screw stock; that is, very hard materials the ram will automatically slow without in- creasing the hydraulic pressure the system. This maximum pressure normally 400 per sq. in. these same machines, made two sizes, bridge structure, Fig. used tie the fixed die bed and the ram backup casting together minimize deflections due the ex- tremely heavy pressures generated the cold working action the stock. Another feature the National machines (not confused with cold headers and threaders made National Machinery Tiffin, Ohio) the mechanism for placing the blank between the dies the right time. The dies are set that the beginning the stroke the space between the dies slightly less than the blank diameter, that the initial squeeze will start rolling the blank between the dies the same position for each operation. Governing the hy- draulic pressure the pressure head determines the infeed rate the sta- tionary die from the point applica- tion this pressure. Cams the reciprocating main slide govern turn the time which pressure applied, usually when the dies have moved when the overlap the rear end the fixed die in. can adapted other types straight die machines back stop blade locates the blank the end the moving die that the same amount squeeze applied each side the blank when the die cor- ners cross and the blank begins roll. The blank inserted manual- into nest, Fig. and held the flat spring finger against the back stop blade, the relief surface the end the moving die and the feed bar, which actuated coil spring with hydraulic reload. soon the blank starts rolling the feed bar retracted and the back stop blade pulls away twice the speed the blank advance conventional ma- chines. one other important respect the National unit differs from older types. Matching dies accomplished adjustment the moving die instead the stationary one. The die itself clamped saddle block, Fig. which turn mounted two ad- justing wedges and wedge and the rocker back the saddle block and the other wedge be- The latter corrects for ver- neath it. THE IRON AGE, November 1944—53 | | - & ; | | : tical elevation alinement the dies. The former two enable the die face tilted, providing accurate con- trol over the taper parallel re- quirements the thread being rolled. some cases desirable, for ex- ample, roll thread having slight- smaller pitch diameter the end than nearer the head the bolt. Com- pound screws the taper wedges make these adjustments very sensi- tive. Matching done the conven- tional manner running the blank through the dies half turn and ob- serving the impressions made the stationary and the moving die. placing pencil mark one side the blank, the impressions can iden- tified and the adjustment the mov- ing die, down, made according- until the impressions match the half turn. mentioned earlier, the idea rolling threads with circular dies not new. The first commercially prac- tical machine, however, was not put the market until about year ago. This machine, known the Reed cyl- indrical die thread roller, Fig. 10, made the Rolled Thread Die Co., Worcester, Mass., one the largest producers flat type dies for recipro- cating type machines well. The principle the Reed thread roller based three constantly rotating cylindrical threading dies, Fig. 11, which act simultaneously blank floating between them. The thread formed without shock controlled pressure applied through the action 54—THE IRON AGE, November 1944 toggle arms which are moved and out oscillation stress ring, the movement which turn con- trolled the action cam and link with spring return. advantage the Reed machine that the feed can varied changing the shape the cam and change gears provide the equivalent straight die many feet length, since the rolls may ro- tate many revolutions, the only limit being economy operation. Thus hard materials the infeed may very gradual. For thin hollow work, for example, which the machine well adapted, possible feed the dies very slowly, equivalent the ac- tion flat die ft. long. With this unit, soft tubing has been threaded with 0.025 in. left between the bottom the thread and the the tube. ordinary straight die work where two contact points volved, pitch thread, for ex- ample, the reduction per contact varies between in. the start and 0.001 0.002 in. the end, since the dies must set nearly parallel order not squeeze too hard the finished end. the Reed circular die machine, the other hand, the penetration per contact can con- trolled throughout the cycle any de- sired amount. practice, however, customary not exceed 0.005 in. the first contact and reduce pen- etration per contact throughout the until the end several revolu- tions are used without penetration iron out irregularities. the earlier Reed machines con- siderable time was taken matching the three circular dies. Although ac- curate results could obtained, com- paratively accessible adjustments the three rolls complicated the situ- ation. the latest approved model two the die driving members may rotated with respect each other Reed cylindrical die thread roller feeds three rolls into the work toggle action. Shown below the toggle die holder assembly partially removed. At’ the toggle joint clamped the stress ring, while A’’ the universal joint drive. Scroll faces inner surfaces stress rings are for major adjust- ments pitch diameter work, while screw link for minor p.d. adjustments. Cam Under plate oil filter. the upper view the whole machine are the multiple splined shafts sliding collars used for synchronizing dies. Change gears are and the third fixed member, means internally serrated sleeve hav- ing 101 teeth with dial markings the outside corresponding the ser- rations. The sleeves may raised and the dies rotated correct for lead error terms per cent lead. The rolls are set taking light (0.005 in.) bite into blank and rotat- ing the dies handwheel the change gear shaft one-third turn match the grooves. Fig. shows the appearance mismatched and properly matched dies their effect the grooves. the new Reed unit, subst threa actua ing Wher gle the creas ally are conto | | Dies diam screv mack for parts | substitution right and left hand thread connection between the cam actuated pivoted link and the oscillat- ing head also facilitates the setup. When this link lengthened, the tog- gle joint will not reach dead center and the p.d. the work slightly in- creased. This adjustment exception- ally accurate and sensitive. The dies the Reed thread roller are ground accurately thread contour standard thread grinders. Dies vary size from in. diameter, Fig. 11, the exact size being multiple the pitch diameter the screw being rolled. The Reed unit not high speed machine. designed specifically for precision work and for handling parts that would difficult roll IG. RTD cylindrical dies. Varying from in. diameter, these rolls have thread forms ground from the solid high speed steel high carbon, high chrome steel. straight reciprocating type machines. Where reciprocating type machine might bat out bolts per min. commercial work and from per min. high strength aircraft material, the Reed unit will average per min.; although has produced high pieces per min. some aircraft material. One its principal applications long studs that are top heavy. Unless po- sitioned exactly vertically die machine, such parts are likely produced with drunken threads, with disastrous effects the die. the Reed machine the three rolls tend center the work and keep its axis vertical while being spun. Circular die machines are also well adapted for threading hollow work and for rolling taper threads, includ- ing pipe threads and aircraft studs with lead-in threads. The controlled feed feature the Reed unit ad- vantageous this respect that (CONTINUED PAGE 132) 13—The Watson-Flagg thread roller incorporates two high speed steel circular dies about in. diameter and having threads with about ground them. The right hand die fed into depth hydraulic pressure. BELOW tially rolled mismatched dies. (Right) With properly matched dies, the impressions made one die will accurately aline with those made the other when the blank has rotated the first 180 deg. straight die the Watson-Flagg machine and 120 deg. the Reed roller. f THE IRON AGE, November 1944—55 4 — q : q d t ; Plastic Coatings For Metals Plastics can and will play important part the coating metals. The author points out that during the war the development synthetic coatings has advanced considerably and further rapid strides will made the postwar period when restrictions are lifted. This use for the newly developed plastic materials will im- prove the surface the metal considerably, will cut finishing costs and will increase the salability and market value the product. 1855 Alexander Parkes began manufacture varnish-like ma- terial produced from cellulose ni- trate, gums and How- ever, the use this material was delayed until John Stevens developed the use amyl acetate solvent 1882. Later through the addition pigments this material became well known the metal coating industry. The lacquers made from cellulose ni- trate are not affected common ali- phatic hydrocarbons and their deriva- tives but are completely soluble acetone. These lacquers will dry read- ily room temperature but generally the metal parts are processed forced drying 150-180 deg. The coating only mildly attacked dilute acids and has good resistance against water and gasoline. Yet does not stand under salt water spray, alcohols vegetable oils. highly flammable and has tendency become brittle and discolor exposure excess light. Nitrocellulose coatings can ap- plied metal surfaces several methods. The most common method spraying. This accomplished the use air pressure applied the plastic material, forcing through the gun and atomizing the material into fine mist. Another way ap- plying the lacquer that employed metal signs and sheets the use roller coating. Other methods coat- ing are dipping and tumbling. Products that have been surfaced with this plastic include refrigerators, fur- niture, metal signs, bedsprings, radi- 56—THE IRON AGE, November 1944 ators, buckles, hairpins and many other items prewar manufacture. Alkyd Resins Alkyd resin coatings were intro- duced into the metal finishing field modifying the characteristics the cellulose nitrates lacquers. The addition most types resins lacquers resulted cracking and other difficulties while the use alkyd resins improved the weather resis- tance and appearance, the early 1930’s alkyd resins be- came well established the industry metal coating. The automobile, agricultural and industrial machinery manufacturers were the first recog- nize the many advantages. These plastic coatings can applied spraying, dipping, roll coating and brushing. Many applications were originally baked but during the pe- riod just prior Pearl Harbor the industry began gradual change-over from this air drying since increas- ing numbers items could not baked even with infra-red lamps due the large sizes involved. The shortages various materials and the need meet certain definite Army and Navy specifications has caused many improvements made this type coating. Alkyd resins have been employed prevent chalking the lusterless finishes for war use. They are being used the coating aluminum and light metal parts prevent corrosion. Since this plastic has not been available for ci- ° CHARLES DELMAR TOWNSEND Process Engineer, Cleveland vilian consumption during the war, doubt its use will expanded the postwar era. The experience gained the past several years will help improve the application the coating metal the years come. durable plastic and has good flexibility but soluble hydrocar- bons. The probable use the post- war era will for coatings used automobiles, farm equipment and trucks. Melamine Resins 1939 the melamine resins were made commercially available the United States. Their existence was known early 1834 when Liebig produced the material. However, they were not exploited until 1939 when the demand for quick-drying du- rable finish was becoming necessity. The melamine resins used surface coatings are supplied the form solution organic solvent such butyl octyl alcohols. Since these resins are thermosetting they produce hard finish the application heat. the coating metals with this material the surface finish will bake temperatures low 180 deg. However, obtain the maximum effi- ciency the temperature should the 325 425 deg. range. This coat- ing has not been extensively applied the civilian goods industry except for the early use coating refrigera- tors and metal furniture. Develop- ments during the war have improved this particular coating and will doubtless have important future the postwar era metal finishing. far less affected water and light than many other coatings and could well used for hospital equipment, bathroom cabinets and other furnish- ings that require white color and du- rability water cleaning and light. Digressing slightly from the metal coating industry, should noted that the building trades during recent year: coum and The | readi Here gone velop used ing tions sibili maro porta devel porte they resin Otto and Indu: Engl State lar have one softe onto place dime thick tion more work mach for for demo such film heat years have been making good use coumarone-idene resin. This material based developments Kraemer and Spilker and dates back 1890. The coumarone-idene resins will blend readily with other resinous compounds well with waxes and bitumens. Here again the plastic coating has gone war and the most recent de- velopments will become known and used the postwar period. The coat- ing effective ship painting and the coating concrete installa- tions where prevents dehydration the cement and eliminates the pos- sibilities faulty cure. The cou- marone-idene resin highly resistant acid, alkali, brine and water. Acrylic Resins Acrylic resins have played im- portant role wartime coatings, and developments the past year are re- ported remarkable, although they too must wait for V-day. These resins were developed 1901 Dr. Otto Rohm Darmstadt, Germany, and 1930 the Imperial Chemical Industries, Ltd., introduced them England. The suppliers the United States were also working along simi- lar lines and the war demands have caused rapid strides made the development this coating. The acrylic resins have water white color and transparency. They are highly resistant mineral oils, alco- hol, vegetable acids and chemical fumes. One difficulty with acrylic resins the pinholes that often occur but this can overcome certain extent use the proper solvents. Develop- ments this resin that have taken place recently will prove advanta- geous the postwar fields. The resins applied the spray method using per cent solids. Both dipping and roller coating can em- ployed also. Phenolic Resins Phenolic resins have been rapidly developed for wartime use and the armed forces have used this coating drinking water tanks, steel canteens and hospital food containers. The oil soluble thermoplastic phenolic resins are being restricted for war use and the great demand for anti- corrosive primer being met the use this material. The reduction tung oil has greatly increased the value this type coating. Another oil-soluble resin, but one thermosetting, also being used parts requiring resistance acids. forms glossy coating and has good dielectric properties. This coating now being used place stainless steel and being applied many containers. The phenolic resins can applied, can nearly all the plastic coatings, the use spray guns, roll coatings dipping methods. Some types thermosetting phenolic resins can baked while others require the use drying oil which will set without heat. Postwar uses this material are numerous and will doubtless include coatings for tank car linings, drum linings, cans and other similar prod- ucts. Phenolic coatings are very flex- ible and durable. There are many other plastic ma- terials such styrenes and the and urea resins that will invade the metal coating and finishing field improve the surface conditions steel and other metal items. When the day victory arrives the tremendous de- velopments that have been made these past few years will assist the perfection better metal coatings. Engineers will find that they can avail themselves the strength and durability steel and yet sacrifice nothing since the plastic coatings enhance the appearance and serve place the metal products the com- petitive field with plastics. Surface Inspection Projected Plastic Film AXFILM the name given the latest method surface inspec- tion and comparison. The process simple. the use solvent, one surface clear plastic film softened enough that when pressed onto surface contact replica produced. This film then mounted placed standard projector such used for Kodakrome transparencies. Enlargements 100 diameters more can made the screen. One use for Faxfilm the metal working industry where samples machined surfaces must compared for quality control. also useful for studying crystal structure and for demonstrating the quality fibers such wood, cloth and paper. The heat the projector and resistant inflammable. Surface contours are seen three dimensions since variations: the thickness the film causes varia- tion the amount light which the film. Comparisons for standards for roughness, waviness and lay can made. Cleavages, cracks, porosity, dents, tool marks and other scratches are also revealed. make plastic print, in. the film cut from roll and pressed the surface examined after the latter has been moistened with the solvent. After being left the surface for from sec., the film stripped from the surface and AXFILM ma- chined steel bar, fin- ished inches RMS, waviness and lay. En- largement Projected reproductions surfaces cost about 6c. each small quan- tities. # — 3 mounted the frame, which has been moistened the inside. The slide then ready for projection. Faxfilm available from the man- ufacturer, McDill, 5109 Mayfield Road, Cleveland. sold inex- pensive kits with sufficient materials make 250 plastic replicas. The film filed for future record desired. THE IRON AGE, November 1944—57 | | > n J t ° ° Measuring and Designating HEREAS the measurement surface roughness compli- cated procedure requiring fine precision instruments and specially trained personnel, the comparison surfaces determine rapidly which surface the rougher, simple matter. Surface comparison can accomplished without use expensive equipment specialized techniques. FINE LAP SURFACE HAV- ING IRREGULAR PATTERN APPEARS DULL BECAUSE DIFFUSED REFLECTION. ABOVE reason why visual inspec- tion cannot depended upon make sur- face comparisons. important factor expediting and controlling the production surfaces. Shop are called upon make such comparisons throughout the various stages production, as- sembly and inspection. Surface roughness comparison predicated upon accepted roughness standards, extensively distributed, which serve liaison agents ad- vise the machinist the limitation the engineer has placed upon the roughness part. Roughness stand- ards are nothing more than limiting values; they not represent require- ments for duplicating roughnesses. Thus, through the comparison sur- faces, the machinist able make certain that staying within those limits. IRON AGE, November 1944 example, drawing calls for RMS microinch finish ma- chined part. What has been specified the designation this: the part must have RMS microinch rough- ness, smoother. There consider- able leeway below the value called for, but none above; the surface must not rougher than the value speci- fied. those rare cases where too smooth surface would unsatisfac- tory, two values are specified and the ROUGH TURN SURFACE HAVING DEFINITE PAT- TERN APPEARS BRILLIANT BECAUSE SPECULAR MIRRORLIKE REFLEC- \ final roughness produced must lie be- tween those limitations. Comparisons Touch Although comparisons can made sight, feel instrument, compari- son essentially tactual procedure. Visual inspection cannot depended upon. The prevalent idea that the brighter surface the smoother its finish, definitely misconception. very possible that turned steel cylinder with the RMS value 250 microinch more will shine brightly, while ground and lapped valve with finish about will gray, dull and lustreless (see Fig. 16). However, the difference the roughness those two surfaces can made immediately apparent merely scraping the fingernail over the two surfaces. addition de- tecting such obvious differences, fin- gernail comparison valid deter- mining minute differences within the critical range. has been clearly proved that through touch, even inex- BELOW Co. standard surface specimen set consisting eight ground steel samples. | | | nes: par pro ity vidi | rou ing rou des ma!) con ard the Loc des con mic Surface Finish perienced personnel can make rough- ness comparisons both rapidly and ef- ficiently. this basis, that fingernail com- parison effective and rapid, the problem controlling