The Iron Age 1942-06-25: Vol 149 Iss 26

JUN 1942 q and steels tanks, guns, ships, munitions the other im- plements war are helping armies march Victory. Goop CARBON TOOL STEELS ALLOY TOOL STEELS AIRCRAFT QUALITY STEELS STAINLESS STEELS NITRALLOY STEELS QUALITY STEELS JUNE 25, 1942 a q q 7 COPPERWELD STEEL WARREN, OHIO COPPCO TOOL STEELS Fellow workersad- mire the Pin awarded operator Didn’t Wait for Compound Produce This Job Nichols, turret lathe operator for WILCOX-RICH CO., Saginaw, avoided holding important job practical tooling setup produce the piece which otherwise would have required turret lathe with compound cross slide. The photograph the left shows how used taper cam the cross slide and roller turret station guide the cutter for accurate steep taper and smooth finish. The cutter also ready for facing off and turning Thousands machinists war work run against new turning jobs and finishes that challenge their ingenuity. Hundreds turret lathe operators, anxious help others, send their “Ideas for Victory” printed “Blue bulletin sent free Warner Swasey thousands turret lathe operators. These ideas aid old-timers well learners. Make sure your men are getting “Blue Chips” their homes. Write Warner Swasey, Cleveland, Ohio. You CAN TuRN FOR LESS WITH WARNER SWASEY itation for Men War Industry and locking the hex yide produc FOR JUNE 25, 1942 VOL. 149, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager ° ° Managing Editor, LIPPERT News Markets Editor, ROWAN Technical Editor, OLIVER Associate Editors JAMES Art Editor, WINTERS Editorial Assistants BENEDETTO Resident District Editors Washington Pittsburgh DONALD BROWNE PHAIR Washington Chicago Cleveland Detroit CHARLES POST San Francisco Editorial Correspondents Buffalo Cincinnati FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON Toronto, Ontario St. Louis BACON Seattle ROY EDMONDS ° DIX, Manager Reader Service ° ° Advertising Staff Emer Findl Herman, Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago Raymond Kay, 2420 Cheremoya Ave., Los Angeles, Cal. Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd New York Robinson Fitzgerald 428 Park Pittsburgh Warren, Box 81, Hartford, Conn. Johnson, Market Research Mar. Hayes, Production Manager. Baur, Typography and Layout. ° ° ° Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts lished every Thursday. Subscription Price North South America and Possessions, $8; Foreign, year. Single copy, cents. ° ° Owned and Published CHILTON COMPANY (Incorporated) Executive Editorial and Offices Advertising Offices Chestnut and Sts. 100 East 42nd St. Philadelphia, Pa. New York, N.Y. U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President EVERIT TERHUNE, Vice-President VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALE his Week Editorial Partly About Hats........ Technical Articles Unique Aircraft Construction Mm. Shells Made Improvised Machine Cementing High Speed Steel Sprayed Metal Bearings..... Electroplaters Meet Features Assembly Line Washington West Coast Fatigue Cracks Dear Editor News and Markets This Industrial News Industry....... Personals and Machine Tool Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Prices. Comparison Finished Steel Warehouse Prices Products Advertised Indexed Copyright. 1942. bv Chilten Company (ine.) 152 185 CONSTRUCTION... Greater Security FOR OPENINGS INSIDE WALLS HAT Mahon Rolling Steel Doors, for exterior provide the greatest possible protection from fire and intrusion well established the minds architects and building engineers respon- sible for completion the present enormous industrial building program and the experience thous- ands plant owners where these doors are now almost constant service, day and night. equally important that this same protection assured for the openings inside walls (interior parti- tions, dividing fire walls, corridor walls, elevator shafts, etc.) Under present wor production conditions, fire and damage hazards are increasingly greater. WELL OUTSIDE DOORWAYS Frequently, too, essential that certain departments kept segregated, without interfering with the inter-department movement materials and authorized employees. The practical answer either Mahon non-labeled Doors Mahon Underwriters’ labeled Doors, for automatic clos- ing the event fire. Mahon engineers will gladly assist you the planning any construction project and furnish you estimates—promptly. The new Mahon Rolling Steel Door catalog—or detail the many improvements and advantages Mahon construction and operation. you haven't copy, send for one today. THE MAHON COMPANY DETROIT CHICAGO q cay | : 3 J 30—-THE IRON AGE, June 25, 1942 ESTABLISHED 1855 ° JUNE 25, 1942 ° Partly About Women’s Hats GENTLEMAN from the Middle West disagrees with thesis that purchasing power marches two feet. One cost reduction, making things available more people through lower cost and price. The other conservation, making what you have last longer and give more service. believe that both these causes effect broadening purchasing power making the dollar farther. friend perfectly willing accept one foot but not the other. swallows the cost reduction idea but rejects the conservation theory. “You say,” said he, “that are now learning how get thousand miles from set tires, whereas were formerly satisfied get thousand. That may O.K. for the consumers, but put the tire makers behind the eight ball?” replied that both and were old enough remember the time when one congratulated oneself set tires held together for 3000 miles. And that the tire business evidently had not suffered during the years that had progressively built more and more wearing power into its product. Then came back with comment about yearly models the automobile industry and how style obsolescence was responsible for building that output million units year. But the answer that was that when you bought 1942 model, your discarded 1941 did not the scrap pile but into the hands succession owners decreasing degrees purchasing power, ending perhaps with Indian Joe Oklahoma 1949. Thus ownership and usage are two different things; one being current and the other accumulative. Faced with this impasse, friend used brutal tactics and referred women’s hats. “Stabilize styles women’s hats for six months and you would ruin the millinery said he. you would ruin the disposition womankind.” Now that was tough one and could not answer except say that social objectives sometimes outweigh economic ones and that little waste our economic resources seemed permissible and preferable the ruin feminine dispositions. With few such obvious and necessary exceptions, still maintain that getting the most and the best service out the things that you have way develop purchasing power with which buy things that you have not and would like have. not believe that waste any kind makes wealth. need more scrap iron and steel, for example, help the war program. One way get would instruct contractors take deeper cuts finishing and spoil more parts, thus feeding the scrap pile. But not think that anyone would advocate that way trying win war. Nor think that the same philosophy, applied the stimulation markets, will help win the peace. | H E | RO N | | ° ° | | | | | if | | | | | if | j | | | nese Plants Are Anxious for War Work They can start production once war contracts and subcontracts Write, wire, Inland for the names and addresses any the metal working plants listed below. They are representative longer list Middle Western plants prepared Inland for the purpose speeding all-out war production. Large Wis. sheet metal bldg. prod. mfr. desires war work. Emp. one shift. Sheet metal ga. Equip. includes 11’ power sq. shear, 36” foot sq. shear, power gang slitters, sheet metal pipe forming machine 6”, hand and machine power rolling ma- chines, No. and No. punch presses, No. 10—10’ power brake, No. ga. cap. 30” throat nibbler, spot welder, 10,000 sq. ft. sp. Remodel replace machinery for special govt. work. Capi- tal and best credit rating available. Large Mid-west spring bed mfr. fireproof bldg. with over 40,000 sq. ft. sp. located rail- road siding. Plant includes full line punch presses, coiling machines and var- ious other equip. used making bed springs. Have coilers for making special springs for aviation industry. Also two shapers, two lathes, milling machine, drill press, grinders, heat treating facili- ties and misc. mach. shop equip. Wis. dairy equip. mfr. emp. 100, has approx. 80,000 sq. ft. fl. sp. available for fabricating and weld- ing custom built equip., ample shipping facilities. Equip. includes slip roller, lathes—polishing, turret, 24”, engine— 12”, and bench; drill presses hyd. horiz.; bending brakes, shears, drills, grinders, millers, shapers, welders, slash- ers, rip saws, jointers, sanders, and fa- cilities for sand blasting and metalliz- ing; hot dip tinning plant; spray booth painting equip., sheet metal and wood- working machines. Anxious for war work contracts. Well equipped Mid-western plant with over 300,000 sq. ft. sp. emp. over 400 men. Desiring prime sub-contracting work. Mfg. fa- cilities include planers, punch presses, forming, mach. shop, pressing, bending, forging, flame cutting, grinding, sheet metal, grey iron fdry., painting, rivet- ing, brazing, gas, are, spot welding, pol- ishing, tool making, packing, shearing, machining, assembling, heat treating, wood working, bending, pattern mak- ing. Entire plant available for war work. Can mfg. parts complete assemblies. 32—THE IRON AGE, June 25, 1942 grow. Ohio mfr. decorated metal dry package cans, signs and displays. Two plants, fl. sp. 370,000 sq. ft.; emp. 250. Dry package assembly line from 16” dia. and hand-fed punch presses, complete deco- rating and baking equip., with facilities for coating and baking sheet metal. Lith- ographing, engraving and screen proc- esses. Largest mfr. kitchen uten- sils the Midwest with com- plete facilities for fabrication and por- celain enameling metal shapes max. blank size) wants volume produc- tion stampings porcelain enamel- ing. Welcome all inquiries this na- ture. Buildings available for limited ex- pansion. Factory has acres fl. sp., 400 emp.; produces its own power and water, and has its own police and fire protection insure uninterrupted oper- ation. Press equip. ranges from numer- ous light punch presses 375 draw presses. (Complete facilities records tractors.) Ind. metal prod. 90,000 sq. ft. fl. completely equip- ped for forming lighter gages sheet metal, 50,000 sq. ft. for assembly oth- production work, emp. about 140. Company operates own fleet trucks. Long established Mo. fabri- cator heavy sheet metal, light plate and structurals. Equip. includes ft. and ft. press brakes, gate shears, ft. rolls (plain and corrugated), punch and drill presses, welding and gas cutting equipment, many years ex- perience Government work and cur- rently occupied sub-contract basis. Working one shift only. Capacity three large plants the Middle West, 1,000 emp. For production 10—24 ga. steel prod- ucts including shearing, forming, stamp- ing, drawing, welding, riveting, dip and spray painting and electro-galvanizing. Adequate capital and highest credit rating. suggest that you get touch with even the types plants and equipment you need are not listed this page, because addition the other plants which already have information, our list available war-work plant capacity continuing Ind. water heater and boiler mfr., over 200 emp., has 000 sq. ft. fl. sp. with approx. 160,000 available for expansion, shipping facili- ties—2 railroad sidings and truck load- ing. War work desired for tank welding, galvanizing and mach. shop. Equip. includes Nos. and turret lathes (15”), No. multiple cut No. No. and drill presses (singles spindles) punch presses. press, gear punch press, die space 1014”, t.; spud press, welding machines— circular, spot, seam, hand and semi-auto- matic; 10’ shear roller gal. 36” 72”, pipe Hyd. testing machines, paint drying boring machine spindle, degreasing machine, press brake and 8’; and nibbler. Thirty-year-old nationally known Mo. machinery mfr. emp. 250 including approx. men eng. staff, has 75,000 sq. ft. fl. sp. for seven day week operation. Equipped form standard and special shapes from sheet steel, channels, angles and Complete mach. and welding shop. Wis. mfr. specializing light and medium stampings has 100,000 sq. ft. fireproof mfg. sp. rail- road side track, emp. about 200, has punch press equip. from 185 t., spot welding; assembling; enameling; and plating; special auto. equip. for mfg. rolled bushings; engine lathes and shapers. Forty-three yrs. experience. Large concern, yrs. mfg. machinery, 20,000 sq. ft. mfg. space with approx. 100,000 sq. ft. for storage. Slab milling machine, gear shaper for internal and external spur cutting, engine and lathes, ver- tical boring mill, gear hobber, milling machine, sensitive, radial and vertical power drills, tapping machine, planers, saws and electric welding ma- chines. Have men three shifts, also training classes. pally war work sub-contracts for me- dium size parts. SHERMAN handling, heat treating, shap- ing, forming, assembling, riveting, welding and painting aircraft sheet metal parts have been introduced the aircraft division the Murray Corp. America. Where these practices differ from the more-or-less stand- ard practices the aircraft indus- try, they are attributable the intention accelerating wartime aircraft production and are ex- plainable, part least, the coincidence volume production requirements (larger than those within the peacetime experience the aircraft industry) and com- bination large available supply press shop equipment, specialized engineering, and extensive experi- ence tool and die making. The Murray aircraft production program represents one earliest efforts the automotive industry assist production war planes. has its beginnings the early fall 1940, with announcement aircraft com- pany late October, 1940, that Murray would assist program manufacturing bomber wing sections. This was followed the late winter months 1941 the former manufacturer automobile bodies swung into mass bomber wing production over six months ago. Assembly operations are broken down, double-action dies mechanical presses are used for deep forming, and number tricky production innovations have been adopted—as, for instance, refrigeration 24SO sheets, flowing machine for strip and extrusions, special rivet etc. signing contracts and the begin- ning large-scale tooling pro- gram. This former manufacturer automobile bodies has followed two typical automotive manufacturing techniques, first, the use double-action dies mechanical presses for deep forming and, sec- ondly, breaking down assem- bly operations degree that per- mits great many workers sub-assembly through the movement the sub- assemblies from station station and from one assembly jig the next along the line. The principal. employed Murray operations Alclad, aluminum alloy sheet, although considerable production less steel parts also carried on. The aluminum alloys, most fre- quently the 24S variety, are re- ceived both the annealed and the heat treated condition, depending upon the subsequent processing and the types parts that are made. any event, the annealed material must heat treated that all the products consist heat treated duralumin, material the condition. Heat treated material painted soon received the plant and parts fabricated from this stock are immediately sent assembly operations the bank parts awaiting assembly. Parts formed from this material are parts re- quiring deep drawing and rela- tively little change from the flat sheet condition. Principal departure from conven- tional processing that involving the handling annealed aluminum alloy. Here the practice one that comparable the long-time aircraft practice the handling rivets. has been the THE IRON AGE, June 25, 1942—33 | | = | sheets are heat treated and plunged into this quenching tank before forming into aircraft parts. This rack carrier plunges into cold water and raised from the water overhead hoist. practice heat treat rivets and then take advantage the time lapse before the rivets age-harden. This done either installing and setting the rivets within short time after the heat treat, refrigerating them and making use the fact that heat treated aluminum can kept soft for considerable period time low temperatures. This, briefly, the cycle now adopted for use with sheet stock. the practice here cut the annealed sheets size and shape required, either square shear- ing blanking and, very occa- sionally, routing. The router used only when blank sizes are too great accommodated the blanking press. Incidentally, some the blanking accomplished with sheet steel masonite dies, 34—THE IRON AGE, June 25, 1942 using the familiar Guerin process. After the sheets are cut size, they are heat treated Lindberg electric oven, quantities blanks being put through the oven gether rack wheeled car- rier. Immediately after heat treat- ing, the aluminum quenched cold water, rolled level and then put refrigerated box and kept this container until ready for use. The primary advantage this process cycle that the parts, after forming, are not subject the dis- tortion that comes with heat treat- ing. Instead the parts age-harden without warpage wrinkling and maintain shape. But secondary advantage, not looked for when the processing was originally worked out, that breakage, tearing and cracking during the stamping op- EAT treated material being placed portable ice box for storing. this end-opening container, dry ice placed the shelf above the parts keep them cold. Top-opening containers are used other instances. eration have been substantially de- creased because the metal seems accommodate itself the shape the die more readily when the interim period between heat treat and final age-hardened con- dition. Actually, this latter advantage has been considerable since scrap loss only about 0.5 per cent, com- pared with considerably higher loss when the soft (SO) sheets are put into the press. also probable that the quenching more uniform and complete when the flat sheets are quickly dipped cold water than when odd shaped pieces are dipped. The handling the flat sheets the heat treating oven also simpler than when odd shaped parts are put through the oven, sin 4 she since possible rack the sheets more easily. The heat treating accomplished temperature 920 deg. F., with time control exercised over each lot. actual tabulation the timing follows: Annealed Thickness 24SO 0.020 in. map. min. 0.020-0.032 min. 0.032-0.063 min. 0.063-0.125 min. 0.125-0.250 min. 0.250-0.500 min. Sheets and parts are normally loaded with air and water circula- tion space around them. The stamped parts that are heat treated are those that are formed principally the Guerin process, and are subject very little forming, perhaps only flang- ing. When the heat treated material cooled the quenching tank, the carrying car lifted out with electric trolley hoist, and the sheets are unloaded. Because the heat treating has made the sheets wavy, the roller leveling required. The roller leveling equipment similar that used steel blanks for auto body parts but has been altered the sheet does not get kicked sharply enters the roll. Instead, slight initial hump wave given the sheet and then run through the normal leveling rolls. has been found possible run through stack The surfaces are protected from scratching sandwiching the sheets between two sheets carbon steel approximately 0.040 in. thick, Fifth series articles Improved Aircraft Fabricating Tech- nique. Four previous articles described developments Lockheed Aircraft Corp., and were entitled Contoured Sheet Parts", "Drawing Dies for Airframe Convex Flanges and and Forming with Rubber the total the sandwich not more than in. Such leveling brings the sheet back normal fiat condition. The refrigerator containers are portable dry ice boxes with double walls and granulated cork insula- tion. They vary size, depending upon the blanks they are con- tain, but are approximately 8x4x4 ft. high most instances. has been found that the door not opened all this ice box the sheets can kept for hr., but considered more practical use the sheets soon possible after heat treating, preferably within hr. Actually, several TION Kirksite dies replace drop hammer operations aircraft parts 100 per cent. This photograph shows the punch partly ex- from the up- per die and shows clearly the forma- tion the draw ring and edge bead. hours the usual time. The tem- perature ranges from below zero just below freezing point. This processing eliminates the requirement for hand working re-striking parts since there distortion after the parts age- harden. Shaping and Forming The general practice cutting blanks for the press room use the square sheer whenever possible, because this method the simplest and least expensive the available processes. Blanking dies are too costly for general use, considering UXILIARY fiber dies are placed over some parts for re-strike give tion the Guerin press process some- times. the ex- treme left and ex- treme right such dies are shown ready for use. — ° ° ° | = the number parts being formed. The Guerin process used quite extensively, also, since another relatively inexpensive method. (It described the series articles “Job-Lot Stampings Parts” THE IRON AGE, Oct. and Oct. 26, 1939.) Whenever parts are too big accommodated the other equipment, the sheets are routed size the conventional manner after stack drilling. Flat parts requiring flanging having relatively little departure from plane surface are formed the Guerin process, because this type die inexpensive and does very satisfactory job, even though parts formed have wavy ap- pearance and sometimes require re-strike some hand work finish them. The Guerin process does not result sharp corners flanges ribs some instances, but has been possible obtain satisfactory results, particularly re-striking and the use auxiliary fiber die. example this auxiliary die part made 24SO material about 36—THE IRON AGE, June 25, 1942 IRKSITE dies are cast ap- proximately shape and are finished filing and hand grind- ing. grinding booth, complete with dust re- moval equipment installed the Murray die shop. This technique eliminated re- quirements for Keller operations. stock and extrusions into shape this Metal Forming Machine. hydraulic ram squeezes the material (aluminum, magnesium and stain- less steel) against the die the rotating head the platform the left shape aircraft parts. ‘ in. long, slightly curved, and with deep and relatively sharp rib formed along the center. Clear definition not obtained with the rubber blanket and single die. Therefore, the part struck over again the press, with fiber upper die placed over the rib, under the rubber blanket. This forms the rib sharp and clear, stiff and straight. This modification the Guerin technique produces very satisfactory part. All parts normally made the past the aircraft industry the drop-hammer method are now made Murray double-acting presses with double-acting dies. Murray has virtually standard- ized Kirksite cast zine alloy. The Kirksite cast approximately final size and finished hand grinding and filing. the same the material used the air- craft industry for most drop ham- mer dies. The life the Kirksite dies entirely adequate for the number airplane parts being built and the material later can remelted and shaped into other dies simple foundry. considered important that this material does not require the use Keller equipment, which very the Detroit area and would have been tied seriously great many aircraft dies had machined. These double-action dies are unique design. They make use draw ring, but never any draw bead. This permits considerable slippage the sheets, the mate- rial not thinned out appreciably below the specified gage. The draw rings are designed accordance with practice developed for the fabrication automotive parts, especially fenders. The draw ring follows the contour the deepest parts the die—as nearly pos- sible—and thereby greatly reduces the amount actual draw that required. Actually the sheet permitted bend adapt itself the shape the deepest part the die before the punch actually begins draw the metal into shape. typical example shown here illustration the forming half the for the na- celle the Douglas wing. Here the die, including the female die half, the punch and the draw rings, are made Kirksite. This typical die and typical part. This type die cast sand mold made from the aircraft com- pany’s original plaster the part. (Here lies another reason for vsing Kirksite: the models and plasters made the aircraft companies are made “shrink rule” and the Kirksite corresponds this “shrink Otherwise, the automotive plants would have been required make entire new set models.) this instance, since draw ring was incorporated the die, was necessary make pattern for the ring, sand mold for casting the ring could made. Press room practice distinctly different from that encountered other instances aircraft parts making. The slow working the part, with the drop hammer, eliminated. Contrary the prac- tice some users mechanical presses, the press not slowed down “inched” down, but op- erated its normal speed. The die design and draw ring design per- SSEMBLY corrugated panels form inner skin for Boeing wing. Panels trimmed and drilled previous operations are assembled, reamed and riveted here. After the various units the die are cast, necessary metal re- moval done the die shop and the dies are spotted-in tables and benches. Then they are hoisted crane and carried into grind- ing booth where spray water ‘arries away—for covery—the material ground off the die. Relatively rough grinding wheels and hand files are used. Automotive tool and die men have had little difficulty accommodat- ing themselves the work. mit this. However, output some- what less than when working with steel parts because the care re- quired handling the sheet and the finished stamping. Typical the press room opera- tions the stamping the nacelle tail cone described above. These operations are performed Bliss crank press the 500-ton double- acting variety. Heat treated alum- inum blanks are brought the press one the ice box contain- ers and the operator removes THE IRON AGE, June 25, 1942—37 | stack the blanks and places them beside the press. Before plac- ing blank the press, the opera- tor rubs the surface with tallow lubricant. places the sheets the lower half the die, being care- ful not scratch the surface, since “scratched aluminum aluminum”. daubs the sheets with soapy water assist washing dirt off the punch additional precaution avoid scratching the sheets. The press sults attained the cycle heat treating, forming double-acting dies and age-hardening the parts, the fact that hand work required virtually zero. fact, the re- work department for this plant con- sists only four small bays one floor, despite the fact that the con- cern substantial production aircraft parts. The great reduc- tion the amount hand work required attributed principally the heat treating setup and the assemblies are transferred laterally hand from one assembly line the final conveyor. This transfer station occurs after the prin- cipal parts the assembly are painted and prior landing gear installa- tion. then forms the part single stroke and the stamping removed from the die and stacked with the others box alongside the press. Sheets tissue-like paper are placed between the stampings. Press output instance like this varies upward from per cent the output normally ob- tained stamping steel parts. The press room equipment Murray includes variety sizes presses ranging upward the 500-ton double-acting Bliss press, 800-ton Hamilton press and Erie hydraulic (use for rubber die work) with 2500 tons pressure. This concern has made more ex- tensive use its press shop equip- ment aircraft parts than any other date. Illustrative the successful re- IRON AGE, June 25, 1942 use mechanical double-action dies. including assembly and those the press shop just described, time requirements have been coming down steadily the thousands new workers the plant became accustomed their new tasks and the new ma- terials. special piece forming equip- ment, used the forming stain- less steel parts, dural extrusions, aluminum alloy strip (also usable magnesium) the Metal Forming Machine made South- ern Engineering Corp., Angeles, which heretofore has not made its appearance the Detroit area. This machine differs from conventional bending and forming machines many respects, the principal difference being the fact that, instead the metal into desired shape “flows” the metal into shape. This accom- plished the use dies and high pressure applied the dies the metal passes between them. This equipment mounted base adjoining steel platform which has its surface cam-like head. The ram operates horizontally against the cam surface the movable head, and against dies which are fast- ened this surface. the end the ram pusher block which used form the material the die contour. operation, strip material clamped the die the ro- tating head, the pusher block en- gages the surface the material and slides over it, forming the die the head rotates. De- pending upon the nature the piece being shaped, two more successive operations, ferent shaped shoes, are required provide the necessary shape and contour. Assembly Operations Assembly operations follow the basic idea breaking down each job into number minor jobs, making use large number jigs and carrying the work from station station either hand mechanical means. The technique preparing and assembling the corrugated inner skin used the bomber wing especially interesting. Sections corrugated sheets, approximately the correct size each instance, are placed special jigs for scrib- ing, cutting and drilling. The jigs consist wood base with surface contours fit the corrugations and welded steel bar frame hinged along one edge, clamped down over the corrugated sheets. This steel framework forms outer margin for scribing the sheet can cut size and also serves drill jig for drilling all the necessary holes. Drilling done through this jig without bushings, each drill being equipped with pressure foot that fits into hole the jig and then permits the drill point enter the aluminum sheet. novel method indicating the size drill used for the many holes the corrugated skin em- ployed Murray. The areas the drill jig around the holes are painted various colors corres- pond with drill size chart color designed and copyrighted the company. The color chart makes use half dozen colors with var- ious arrangements and combina- tions indicate just what size drill each one stands for. example, plain blue paint the drill jig corresponds with plain blue rec- tangle shown the color chart, indicating No. drill. For var- iation from the No. drill there may gray circle painted around the hole gray border painted around the rectangle. Each these markings some other size drill, corresponding similar diagrams the chart. This chart takes care all drill sizes from No. 0.4375. There are 100 drill size variations provided. Assembly these corrugated sections form the inner skin the wing done vertical as- sembly jig large enough accom- modate the entire skin panel for wing. The outer wing skin (smooth) spot welded form single large sheet and the two skins (inner and outer) are assembled similar jig later stage. ABOVE YDRAULIC tests for all tub- ing and pipe lines. Electrical power outlet for this port- able electric com- pressor carried overhead trolley parallel with as- sembly head. RIGHT OTATING as- sembly jigs fa- work parts. This one for assembly side panel stringers and skin for The entire fixture built around tubu- lar shaft mounted triangular end sup- ports. The wings being built this plant vary greatly their designs. The former has spar made ex- tended flanged sections milled shape Farnham miller and riveted shear web. The latter wing has main spar made large size drawn steel tubing, approxi- mately rectangular shape, which assembled riveting. The wing has stamped aluminum ribs bulkheads and number string- ers which the skin attached riveting. The wing has ribs formed channels—forming the contour the wing section—and truss built round aluminum tubing riv- eted into the U-channel. Covering the wing consists the double thickness skin, the corrugated skin the inside and the smooth skin the outside, attached mainly riveting. The wings for light bombers are almost entirely flush riveted, while the heavy bomber wings have conventional heads. These differences design have led difference assembly meth- ods, most which have been dis- cussed elsewhere. interest, THE IRON AGE, June 25. 1942—39 = however, that the final asembly jig for the heavy bomber wing—con- sisting sets left and right jigs—are all completed far ad- vance production demands. The tooling these wings ample supply delivery schedules that are already projected into next fall, when the peak demand will These assembly jigs were the first Detroit require two-level point which the wing assembly shifted laterally from one line another. Followipg practice general use this plant, the final riveting skins and minor parts done This done keep the assembly jigs service other wing sec- tions, rather than tie any jig until all detail work the first wing finished. rotating fixture. This one extending horizontally from sup- port and base plate. used for the assembly the tepee-like tail cone for nacelle. work platforms. level lighted fluorescent tube lights give high intensity lighting and evenness light distribution. The bomber nacelles make ex- tensive use curved bands strip aluminum alloy and curved alum- inum alloy extrusions, both which are formed the Metal Forming Machine previously de- scribed. For the assembly four differ- ent nacelles (left and right inboard nacelles, and left and right out- board nacelles) four different sets assembly jigs are required, and jigs all are use this department. The wing sections are assembled jigs similar many discussed other times The one spectacular innovation the com- pletion these wing panels the overhead conveyor system which stretches from one end the plant another, including transfer IRON AGE, June 25, 1942 special routing machine has been developed trim the tail cones the engine nacelles. The trim- ming required because the small areas metal covering riveted to- gether form the skin the na- celle not present clean, straight edge along the line where the na- celle and tail cone join ‘together. This, course, occurs because the difficulty trimming small skin panels exact shape when they are cover such difficult curved surface. The tail cones, after riveting, are mounted tepee- like the table the special router and the routing tool follows the edge steel plate built into the fixture serve guide the routing cutter can trim the skin along straight line around the circumference. interesting piece equipment one employed ma- chine accurately the landing gear attachment points the wing. The entire center section the wing placed structural steel fixture and locked position; then four special milling heads come into action mill out the landing gear attachment points. Spot Welding Spot welding has been limited those points which the design the aircraft parts permits this method assembly. The most im- portant application the welding together the strips aluminum which form the outer skin the wing panels. battery Taylor Winfield Hi-Wave welders, each which has power-driven indexing table carry the aluminum panels past the spot welding electrode, one the plant’s interesting in- stallations. These welders use the principle electrostatic discharge from bank condensors. The work tables are mounted front the welders and are about ft. long and ft. wide. Each table travels ways bed approximately twice this length. Two types tables are used with these welders. One consists wooden slats closely spaced carry the aluminum sheets. more recent development makes use several large sheets pressed laminated plastic board (Formica) the table-top cover- ing. Each type table-top in- tended prevent marring the aluminum sheet. cog and pawl, operated draulic pressure and timed con- junction with the spot welder. The spacing between the spots in. and spacing adjustable. These strips are joined lap welding. The overlap each two strips approximately in. Down this overlap required place three rows spot welds. Thus the sheets and the tables which they rest must traverse three times complete the welding job. The sheets are 17% ft. long and the panel after welding ft. in. wide one edge and approximately ft. in. wide the other edge. The number spots required put these sheets together 11,282 for each wing skin. The most recent these welders has been improved design make possible weld 100 spots per min., compared with spots per min. previously at- tained. The welding tips under these conditions ordinarily produce 100 satisfactory spots without re- dressing the electrodes. For re- ~ \ indexing table for Hi-Wave welder which fastens smooth aluminum skin panels together. The table automatically indexes for spots approximately in. apart. dressing, the tips are ground in. radius. inspection requirement that after each redressing two sample spot welds must made before each seam started and one after each seam finished. These samples are pulled tension and are required give result above the minimum requirement for the sheets being welded. For each 11,282 spots, there are 312 tensile samples pulled. This one the first installa- tions power driven indexing tables high speed spot welder. Since the principal cause poor UTOMATIC bucking bar, air operated. This bar edge which welded and then wire brush the surfaces that are joined. The etching solution weak hydrofluoric acid, into which the sheet edge dipped for 3-min. period. The wire brush- ing done with 4-in. diameter wheel consisting 0.003-in. wires. Naturally, the etching cleans both sides the sheets and removes the oxide that the aluminum The brushing done only the sides that are contact during welding. Special Riveting Equipment Two riveting devices that are demonstrating possibilities sim- plifying and speeding this most tedious all aircraft procedures, are now use. One these con- sists simple pressure element incorporated the rivet gun and set off electrical circuit es- tablished the rivet This device decreases the demand for exact timing and teamwork be- tween the riveter and the rivet backer, and eliminates the need for signals between the two the co- ordination their work. The sec- ond device air-operated auto- matic bar backing which acts sim- ilarly back the rivets, except that this bar long enough cover row dozen more rivets. either instance, merely necessary for the riveter feed the rivets into the prepared holes and hold the gun against the rivet head. The rivet gun begins operate and the rivets being properly backed and alined are welding has been found im- proper etching the sheets, and consequent fouling the tips worker for other 4 bucks and alines rivets, freeing one the tips may become dirty—from will freeze position. This metal pick-up also the principal reason for the frequent redressing the electrode tips. The cleaning practice followed here etch each sheet along the THE IRON AGE, June 25, | 4 } | | | i | welder used stainless parts. This used spot weld stringers nacelle skins. Rotating bucks are employed facilitate this assembly work. headed the opposite end. Both these were devised the prod- uct research engineer. incidental but important ad- vantage the automatic bucking bar that longer does worker have endure the snare drum effect rivet bucking all day long. The bucking bar takes over the noise well the job alining and backing the rivets, and thereby frees the worker for other assembly work. The success the automatic bucking bar has opened new and broader applications, one which fixture which will buck the rivets for entire assembly. This will enable several workers rivet entire assembly one time without removing from the fix- ture, thus increasing man-hours labor usefully employed and greatly accelerating production. these instances the bucking bar equip- ment will incorporated into the jig. Stainless Steel Fabrication addition forming aluminum parts, this concern engaged the forming number im- portant stainless steel parts. The ammunition boxes machine guns. Many stainless steel parts and nearly different sub- assemblies, including lefts and rights, are being fabricated. 42—THE IRON AGE, June 25, 1942 Most the stainless parts are spot-welded together, although few are riveted. Included the sub-assemblies are parts engine nacelles. These are assembled which holds the framework place, with the skin covering held the frame- work light steel bands running circumferentially around assembly. This holding method permits the parts drilled few places Cleco pins can in- serted hold parts together for welding. The spot welders used this operation consist both the pedestal-type welders those hung from overhead trolleys. After the Clecos the sub-assemblies are moved second buck assembly jig per- mit welding with long arm welder hung from overhead. This set-up enables the operator spot the welds rapidly long rows, with one arm the welder working inside the jig and the other arm moving along fiber guide the skin sur- face. The Springback Problem There are three principal meth- sheets, according Frank Mc- Gary, manager the engineering and mechanical division, which re- quire intelligent application sults and particularly overcome the serious springback problem. These are the use double-action dies attain desired form; the use brake dies for accurate control angles and the springback angular shapes and, finally, the use rolls form moldings and simi- lar shapes without springback. Murray makes use each these techniques, including double- action dies (made cast iron automotive work), brake dies and Tishken and Yoder rolling equipment. example die design and press technique the forming stainless the stamping ex- haust shroud pipe. Here, fender practice and the Mur- ray technique for minum sheets, the draw ring (with restraining head) dips down follow, closely possible, the deepest part the stamping. This results virtually preliminary bending the material shape about equivalent the in. diam- eter that required the final part. The draw ring clamps this point and the beads hold the material while the punch comes into action form the part the die. The Metal Forming Machine de- scribed earlier also used stain- less parts. All stainless steel parts are en- gineered use the softest type material wherever possible, but es- ~ pecially parts requiring deep drawing. The easier jobs are made full-hard stainless steel ob- tain the higher physical character- istics inherent this material. The matter selecting the type used any particular part set- tled the designing board. the usual practice build samples hand because, addition the conventional reasons, the hand building assists finding the exact areas that will difficult form with dies. this way the hand op- eration helps point the way later successful tice, indicating modifications de- sign the selection the mate- rial that may prove helpful. Paint Shop Partly means identifying the two types material and partly because fits into the pro- duction scheme, the heat treated aluminum sheet painted immedi- ately upon arrival, after shipping containers are opened and the ma- terial has been inspected. The paint shop for this designated the “hard sheet” paint shop. Here the sheets are hung from mono- rail, with attachment made the sheet clamps that have broad, flat pads them the sheets can hung vertically from the conveyor. The sheets are passed through alkali wash and then into the paint spray booth. The paint spray nozzles are operated electric eye control; soon sheet enters the paint room, the spray guns are actuated and begin operate. They traverse back and forth while chains over sprockets also operate the paint guns along vertical traverse. The aluminum material first fabricated into parts, de- scribed earlier, and then painted conventional spray booths. inhibit corrosion and increase the adhesion and durability paints, the Alrock process used this plant substitute for anodizing. The Alrock process consists oxidizing the aluminum alloy parts immersing them hot solution (212 deg. F.) sodium carbonate and potassium dichromate for about min., fol- hot per cent potassium dichro- (The anodizing process conventionally used electrolytic formation oxide aluminum, using chromic acid electrolyte.) The Alrock process less expensive than an- odizing and frequently known not recognized universal sub- stitute for the anodizing process, however, lacking acceptance the naval forces. Sprue Mill Recovers Sand SYSTEM cleaning excess sand off the sprues and gates castings before the metal re- melted cupolas, and means separating all miscellaneous iron from all waste sand operation the foundry Motor Di- vision General Motors Corp. The equipment consists sprue mill, loading hoist, apron conveyor, belt conveyor, and waste sand elevator. There also dust col- lector remove large amounts the dust created the sprue mill. This equipment will handle mixture sand and iron straight loads gates and sprues the rate about tons per hr. Iron particles larger than in. diam- eter are dumped apron con- veyor which returns them the iron yard, underneath the charging crane. This iron free and clean from all sand, due the tumbling action the sprue mill. The sand and small particles iron pass through screen the end the cylinder belt conveyor. This belt conveyor has magnetic pulley which separates all magnetic ma- terial from the sand. The sand delivered bucket elevator overhead storage hopper, placed high enough that dump truck can loaded from the discharge spout. Fine iron, recovered, carried small belt conveyor the yard underneath the charging crane. connection with the tumbling mill there large fan and dust collector that removes the fine dust from waste materials. Such dust collected wet collector. About tons sand day are removed from the overhead hopper and re- turned the foundry sand system. The remainder hauled the dump waste. Since this system was put into operation, Pontiac has made practice putting all waste sand through the tumbler. re- iron per day, formerly lost through faulty magnetic separa- tions and the form sweepings the floor. THE IRON AGE, June 25, 1942—43 | 7 ‘ol . its manufacture the 20- mm. Hispano Suiza shell for use the gun the same name, Missouri engineering com- pany has stuck fairly close the traditional shell making methods for most its operations. How- ever, the interest saving time eight-station indexing dial applied punch press for speeding the banding 20-mm. shells. The swaging die head mounted the ram. long machine tool deliveries well that economy, the firm’s engineers designed special tooling for four operations which enabled them use standard machines which were already available the plant the time the govern- ment shell order was received. ya Length thread These operations are (1) ing the band seat, (2) swaging the band, (3) forming the band and (4) facing the base. the first and third operations, U.S. Standard hand millers* are used. the swaging operation, Toledo 20-ton punch press employed. The facing handled drill press. Tooling these three jobs was completely designed and built the company’s plant. Results ob- tained from all form operations have been more than satisfactory from the standpoint fast pro- duction and quality work and Top bed press 2—Details the connecting rod and bell crank for indexing the punch press dial shown Fig. using interlocking tubes, limited amount lost motion can provided. 44—THE IRON AGE, June 25, 1942 In 72x yte 7] ‘aia y Screw ~ / / sy | can similarly applied almost any firm engaged the produc- tion shell shot expecting engaged. Punch Press Swaging swaging the band, the punch press was adapted save the cost the standard tire banding ma- chine generally used most shell shops. eight-station indexing fixture dial mounted the plate, Fig. Indexing movement the dial actuated Fig. lost motion the crank- shaft provided for through in- terlocking tubes necessary step. This required because Improvised Mach Tools Banding the shell done punch press with spe- cial tooling. Knurling the band seat and turning the band place are both performed converted hand millers. full revolution the crankshaft without lost motion would index the dial one full quarter turn in- stead the deg. needed for the eight-station fixture. Actually, the indexing plate indexes the up- stroke the press. The press stroke in. which about the minimum which can WE fully used. Three pawls (Fig. are used respectively index, pre- vent forward movement and pre- vent backward movement the dial. After the indexing dial locked place, the swaging die head mounted the ram comes down and swages the band from six the indexing dial, show- ing use actuating and two locking pawls. The forward locking pawl cammed out position auxilia overarm the slide block. pin carried THE IRON AGE, June 25, | | | | | \ \ | \ \ | \ YA Section with two stations out center only 0.03125 in., yet this was enough cause the die head seg- IG. 4—Sketch ments pull the band out into with trunnion type shape resembling Ubangi lip. foot peda/ fixture further insure accurate line- ables