The Iron Age 1942-01-08: Vol 149 Iss 2

& eee eee nelting sumers Chi- Library JANUARY 1942 for fierce fight for new redesigned with Timken sheet, plate and bar mills equipped with Roll Neck Bearings are rolling steel faster, and more economically than ever before. present performance will equal future another matter. q thing certain however; rolling mills with Bearings back-up roll necks, work roll screwdowns, pinion stands, mill drives, table and other auxiliary equipment will give their tremendous advantage. How about mills? TIMKEN ROLLER BEARING COMPANY, CANTON, OHIO typical Timken 4-row back-up roll neck mounting Bearings fer automobiles, motor trucks, for 4-high mill illustrated above. Bearings are railroad cars and locomotive: and all assembled their chocks and stored unit assem- ROLLER BEARINGS less Tubing; and Timken Rock Bits. JAN | 4 4 50 j Chi- proauction costs. SETUP” Reduces Setup Time and Tooling Casts BAR WORK After studying hundreds turning jobs, these Uni- versal bar tools, cutters and collets have been selected and are recommended Warner Swasey, per- manent setup handle wide varieties bar work. this tooling plan the large flanged type tools remain mounted the turret. This arrangement permits infinite number setups simply (1) changing collets and bushings, (2) grinding cutters, (3) setting cutters, and (4) setting stops. Adjustable features these bar tools quickly set cutters new sizes. Only extra long run jobs may pay change this tooling setup! Check your turret lathes doing bar work against this recommended per- WARNER manent setup. you need additional Warner Swasey Tools adopt this SWASEY time-saving setup, select sizes from Turret your Warner Swasey Tool Catalog. Cleveland REAR TOOL POS TURRET UNIVERSAL BAR EQUIPMENT Permanent Set-up COMBINATION STOCK STOP AND CENTER SINGLE CUTTER RNER UNIVERSAL Single Cutter Turner Universal Bar Turner Multiple Cutter Turner Combination End Facer and Turner Quick Acting Slide Tool Center Drilling Tool Adjustable Knee Tool Die Head Clutch Tap and Die Holder Set Forged Cutters Square Turret SHORT FLANGED TOOL fe] DER COMBINATION END FACER AND TURNER DIE HEAD CENTER DRILLING TOOL ADJUSTABLE KNEE TOO) BAR TOOLS Floating Tool Holder Set Taper Drill Sockets Drill Chuck Combination Stock Stop and Starting Drill Combination Stock Stop and Center Short Flanged Tool Holders Long Flanged Tool Holder Set Collets Collet Bushings Complete descriptions these tools are found the Warner Swasey Tool Catalog. you not have your copy, write for it. a / | \ LASS ORILL CHUCK YOU CAN ASTEF FOR JANUARY 1942 VOL. 149, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager ° ° ° Managing Editor, LIPPERT News Markets Editor, ROWAN Machine Tool Editor, OLIVER Associate Editors JAMES Art Editor, WINTERS Editorial Assistants Washington Editor MOFFETT Resident District Editors CAMPBELL HERMAN KLEIN DRILLING elt Pittsburgh Chicago Cleveland Detroit CHARLES POST San Francisco Drill Editorial Correspondents Buffalo Cincinnati FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham Stock Drill Stock Toronto, Ontario St. Louis Tool Nework, Seattle ° ° ° Tool DIX, Manager Reader Service ° ° ° Advertising Staff Collet Emerson Findley Herman, Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York Robinson Don Harner, 1595 Pacific Avenue, Long Beach, Cal. Johnson, Market Research Mgr. Hayes, Production Manager. Baur, Typography and Layout. ° Member, Audit Bureau Circulations Member, Associated Business Papers Foreign, $12.00 year. Single copy, cents. | ° ° Owned and Published CHILTON COMPANY Robert Blair Union Cleveland East 42nd St., New York Indexed the Industrial Arts lished every Thursday. Subscription Price United States and Possessions, Mexico, Cuba, and South America, $6.00; Canada, $8.50; (Incorporated) Executive Editorial and Office Advertising Offices Chestnut and Séth Sts. East 42nd St. Philadelphia, Pa. New York, U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President EVERIT TERHUNE, Vice-President Vice-President Editorial Armament Technical Articles Small Arms Ammunition Manufacture Briggs Aids Aircraft Production Heat Treating Cast Hulls How Smooth Should Bearing Be? Plywood Match Silver Plating Technique New Machine Tools Features Assembly Line Washington West Coast Fatigue Cracks News and Markets This Industrial Week News Industry Personals and Obituaries Construction Machine Tool Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Comparison Prices Finished Steel Prices Warehouse Prices Sales Possibilities Products Advertised Copyright, 1942, by Chilton Company (Inc.) BAUR, WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES 100 102 104 105 110 ° — Above: Way Type Drilling Machine for the simultaneous drilling Kingsbury Mechine Cerporation, Keene, Machine Base ihsstrated below. IRON AGE, January 4 q Builders Precision Machines KNOW the VALUE Mahon Precision-Built Bases Producing precision multiple drilling machine, such pictured this page, requires not only excep- tional skill and knowledge but heavy expenditure time and money. sound economy, therefore, make sure that the base upon which mounted built with equal precision. The Kingsbury Machine Tool Corporation, Keene, H., who builds this machine, relies Mahon experience and exacting fabrication methods insure accuracy fit and finer finished appearance—and save subsequent costly machining. Depending Mahon for Machine Base requirements likewise has become thrifty habit with hundreds other foremost machine tool manufacturers. Send YOUR blueprints for quota- tions. They will given prompt attention. THE MAHON COMPANY DETROIT, MICHIGAN Manufacturers Machine Bases and Many Other Products This reproduction from unretouched graph clearly shows the clean-cut, smooth appearance and accuracy workmanship Mahon precision-built Welded Machine Bases. | | | | JANUARY 1942 ESTABLISHED 1855 mament east UNITIONS are just vital the war bread for our soldiers. must have them ever increasing quantity. You cannot bake bread without yeast and you cannot make muni- tions without machine tools. Machine tools are the yeast armament. They must come before the planes and guns and tanks can had. The machine tool industry undoubtedly has had, and still has, the hardest job that Uncle Sam has given any our industries. already has made fine record expanding from $200 million output 1939 that That will take some doing, but must done. And nothing must permitted stand the way its realization; not even price ceiling. The machine tool industry not adapted mass production because the great and necessary variety its product. “precision” industry which accuracies the part human hair are rules rather than exceptions. Skill, experience and training are required high degree and there small room this business for labor. lacked bread because need for more yeast, would not dream putting price ceiling this vital element which represents such minor part the cost bread. Instead, would say the yeast makers: every necessary expenditure quickly needed and whenever needed assure adequate supply.” yeast minor element the cost bread, are machine tools munitions. The $1.4 billion goal for machine tools 1942 dwarfed the $40 billion appropriation for machine made munitions. Unlike the materials such iron and steel which into products, the cost the machine tool distributed over all the products makes and, there- fore, diminishes with each successive output. This industry has already had its troubles and will have more them. has scraped the bottom the supply skilled labor and has had install extensive and expensive training courses. has had multiply its cost inspection and face increased spoilage because dilution skill. has had raise wages and give bonuses stimulate production. Overtime time and half now averages hours week per worker, and the cost subcontracted parts frequently double the home factory cost. With its hands free meet these contingencies they arose, this industry has undeniably made one the best records any industry fulfilling production quotas, and with price rise only per cent since January, 1939, date. Compare this with the rise farm product prices per cent the same period. There will more these contingencies meet 1942 and machine tool management must free meet them day day, they occur. When need this munition yeast badly, cannot afford tie the hands its makers even for day and certainly not for three-month period under frozen price ceiling. ad | | D- Inland Building Blast Furnaces Help Win the War building three huge blast furnaces help win the war! They are part the program provide more pig iron and help overcome the shortage steel scrap. One will our own furnace—built with our own funds—and will located our Indiana Harbor Works. The iron from this furnace will used maintain and augment our steel-making operations. Close the Inland plant—on government-owned property are constructing other two blast well coke ovens, docks and all else needed produce 900,000 tons pig iron annually. Inland the agent the Defense Plant Corporation building this plant. will owned the government and leased Inland. After the war the government will dispose its best advantage. Thus, construction, well production, Inland’s men and facilities are devoted wholeheartedly our country’s primary objective—the speedy and victorious conclusion the war. INLAND STEEL Dearborn St., Chicago he 3 4 4 . f + ° ° ° NEALEY ° ° ° the six small arms ammunition plants included the expanded Ordnance Depart- ment program was finished and started production recently, four months ahead schedule. the Lake City Ordnance Plant, Lake City, Mo. (near Kansas City), $70,000,000 project. was built for the Ordnance Department un- der the supervision the Rem- ington Arms Co., Inc. This Lake City plant will produce volume small arms ammunition every month greater than the total pro- duction the United States dur- ing the First World War. The out- put this plant, added that the five others, highlights the startling volume fire power modern army must able deliver. The site the Lake City Ord- nance Plant area approxi- mately 3000 acres which has been erected 219 buildings with combined floor space 1,600,000 sq. ft. Within this area are miles road and the same mile- age railroad. surrounded 90,000 ft. high wire fencing. The ammunition manufactured here consists 0.30 and 0.50 cali- ber cartridges. The designing shells bul- lets fired from guns and cannon broad field engineering it- self. Special attention has been recently the armor pierc- projectile. Streamlining with long sharp nose with ogive curve required for maximum velocity and accuracy during flight Small Ammunition Manu Arms the most successful but least known organizations for the preparation for defense case war has been intensively active America for 164 years. This organization known the Ordnance Depart- ment the United States Army. started with the building the Springfield Armory the behest General Washington 1777. now has six manu- facturing arsenals, three proving grounds, ordnance district offices, field service depots, etc. addition, has under way the building ordnance- owned plants for the manufacture war materiel—some major items. This multi-billion dollar program already half completed. Manufacture small arms ammunition carried one these new plants described this article. along the trajectory, but for op- timum penetration different shaped nose indicated. Two other opposing requirements are hardness for penetration and soft surface that will cut the rifling induce rotation and thereby minimize barrel wear. These conflicting characteris- tics are reconciled armor piercing small arms bullet put- ting hard steel core into soft gilding metal jacket. The space between the two differently shaped noses filled with lead alloy restore density and ballistic bal- ance. The lead also aids penetra- tion especially when striking angle, which almost always the case. Raw material for cartridge cases for 0.50 caliber ammunition, received the Lake City Ord- nance Plant consists brass shapes already blanked, cupped and annealed. The alloy usu- per cent copper and per cent zinc. These cups are given four draws with anneal after each the first three. They are washed and lubricated after each anneal preparation for the next draw operation. Draw presses are the Bliss type. The presses for the first draw are equipped with slot type tum- blers with hoppers, which drop the cups, mouth up, onto slowly re- volving horizontal plates which feed them into the presses. Spring held steel guides position them over the die cavity order make the draw even throughout the circumference the cup. The descending punch forces the cup into the die and all the way through. the die slightly tapered, small end down, and chamfered the bottom edge, the slight spring back the brass after has passed through the die, prevents the cup from return- ing through the die and strips from the punch the upward stroke. The material further lubri- THE IRON AGE, January 1942—29 — | 4 j q 4 q e 4 ° ° ° | a ins LEFT SERIES 0.30-cal. duplex first-draw presses the Lake City Ordnance plant. presses the annealed cups received from the brass company are sub- jected the initial draw opera- RIGHT which have already been through the first draw and then annealed are passed through this press, which redraws them through die having smaller diameter than the outside the component means punch en- tering the component and forcing down through this die. cated prior each draw flow- ing compound onto enters the press. The cases for the sec- ond draw are positioned, mouth up, rotating feed tumbler the spindle type discharging into three tubes feeding into channels leading into three dies the press. Cams feed them into the die cavities, punches force them through and they are stripped the first draw. The third and fourth draws are similar. After being stripped from the draw punches, the cases are dis- charged onto belt conveyor and moved mezzanine floor and thus routed the annealing and washing operations. This proce- dure followed after each opera- tion during the case manufacture. Annealing Annealing performed before the second, third and fourth draw battery natural gas heated furnaces the continuous type. These are about ft. long and ft. wide, overall. Heat sup- plied gas burners, and the heat radiated onto the work. The belt type conveyor composed heat resisting woven metal form- 30—THE IRON AGE, January 1942 ing closed loop. This stretched between drums pulleys each end the furnace, one motor driven and the other idler. The lower half the conveyor re- turns open space below the furnace. The work distributed evenly over the belt gate type hop- per. Temperatures range from 1150 1400 deg. with heating periods from min. Each furnace divided into two zones (heating and soaking respectively) with automatic temperature controller both, and recorder for the soaking zone. This zoning provided assure closer tem- perature control and maintenance the same heat throughout the length the furnace. The annealed cases are dis- charged onto screen type belt conveyor washer where they are treated acid wash, two water rinses, and neutralizing soap rinse. This accomplished series conical shaped re- volving drums which discharge progressively from one into the other. These are partially sub- merged solution water, all heated with steam. The dryer continuation the washing unit and involves cylinder, revolving over gas burners, and equipped with thermostatic heat control. The dryer discharges into con- veyor system for distribution the proper draws. The open ends the cartridge cases are cut off after the third | | j j and fourth draws trimmers the rotating knife type. Positioned spindle tumbler, they feed into the trimmer chute. This chute drops them, one one, into re- ciprocating holder which delivers them the center line man- drel and punch. The punch moves forward push the case onto the mandrel, the knife moves and makes the cut, the holder moves out the way into the position receive the next case. strip- per plate removes the trimmed ease and trimming from the man- drel. The trimmed case drops onto conveyor while the trimming blown into container air from nozzle located above the end the mandrel. The swedging operation, for- merly performed this stage flatten the head, has been elim- RIGHT GAS-FIRED furnace. These furnaces are used an- neal components between the draw operations. the draw operations, the work performed the brass re- duces the grain size the brass and consequently hardens the metal. This annealing enlarges the grain size, thereby softening the metal the point where may readily worked the next drawing operation. inated redesigning the heading bunter and giving the cartridge case softer anneal. Pocketing The pocketing operation for pro- ducing the primer pocket the racute press. The operation accomplished the action squeezing the case between punch and bunter die. Fed gravity chute into guide, each case turn held the center line the press while the punch pushes forward into the die meet the bunter. The punch then withdraws and pushes the next case into the die, thereby pushing the previous one out knocked down reciprocating finger into discharge chute. The heading (and stamping) accomplished press similar the pocketing press and operating the same manner. The extractor groove turned the head the case Reynolds type screw machine. This machine involves rotating head with five rotating spring collets that index around the case for three separate cutting operations. brake stops rotation the collets allow cases injected and ejected adjacent stations the machine. Another anneal now order, soften the case for tapering. taper necessary for reduction bullet diameter and for easy extraction after firing. The entire heated but only the body and neck portion are heated the transformation point. This ac- complished circular, hori- LEFT Colt washer with conveyor facilities. Con- veyors transfer compo- nents between opera- tions the case area the Colt washing units, which thoroughly clean them heated cleansing solu- tions and then dry them preparation for the next operation. THE IRON AGE, January : a / j . lis- x wo j re- the ub- all ing dge | —— i ABOVE AL. 0.30 horizontal pocketing press which locates the indentation the head the case which will later com- pletely finished receive the primer. Feed from the tumbler automatic. zontal plate with depressions, slightly larger than the case heads, close the outer edge. the bottom each depression revolving fixture. The cases are fed gravity from tumbler onto these fixtures, heads down and standing vertical position. Water the depressions keeps the heads cool and hard while the plate carries the revolving cases through series gas burner flames. revolving arm and finger tips the annealed cases off into box. Cases are not transferred conveyor system this point, be- cause possible damage due the body shell cse being too soft. two part die and punch Bliss press are employed for taper- ing. Feeding multi-cavity 32—THE IRON AGE, January 1942 dial and after the case has been pushed through both dies, which taper and form the neck and shoul- der, punch sizes the mouth the correct diameter. avoid overstressing the neck when the bullet inserted and insure the obturage effect, that the neck the cartridge case will expand against the gun barrel under the force the exploding charge and thus prevent the gases from blowing back, second neck anneal given soften again this section the case, following cold working the tapering oper- ation. row small furnaces employed, each consisting two now ready for insertion its primer. Armor Piercing Bullets the Lake City’ Ordnance plant, the raw material for 0.50 cal. bullet jackets (90 per cent copper and per cent zinc) received the form cups. shape them, these cups are sub- jected four separate drawing operations many different presses, but due the nature the alloy, less frequent annealing operations are necessary than drawing and forming the brass cartridge cases. BELOW SERIES 0.30-cal. body annealing furnaces. these furnaces the cases are annealed preparation for the taper operation passing them before series gas burners vertical position. doing, the head the case held water bath and result the head the case retains its hardness, which essential quality the finished cartridge. The mouth the case softened the point where the necking and tapering operations may accomplished. revolving screws which carry the cases past series gas flames. Annealing carefully limited point the shoulder disclosed distinct line discoloration which appears during heating. This line much more distinct the inside and case frequently selected and cut open observe more closely the position this line. omplete the case, trim given bring proper length. This machine uses star type cutter, and trimmings are separated blast air syn- chronized with the cutting action. After inspection the cartridge case The four are equipped with automatic hopper feeds, multiple punches and sta- tionary dies; and the compo- nents are fed the presses, the punches push them down into and completely through the dies, the drawn components stripped from the punches during the return stroke the press. This forming drawing pro- gressive and continues from one press another until the original cup shaped into long, tube- like jacket which has one end open. During the drawing process all dimensions the component are kept extremely close tol- | | | its erances, and the final jacket must conform established standards size within 0.0005 in. After being drawn, the jackets are washed, dried through cut-off machines where they are trimmed exact length. Another washing and drying, to- gether with application spe- cial lubricant, fixes them for the first assembly presses. Two straight-line-action assem- bly presses are required pro- duce finished bullet. The first assembly machine has separate pairs punches and dies; the sec- ond assembly press, seven. the first press the jacket around and over the back end the steel, armor piercing core. Like the first assembly, this press equipped with automatic feed hopper, and the fore- going steps manufacture, the operations this press must func- tion obtain very toler- ances dimensions. The last sta- tions this machine act pro- duce very precise and uniformly perfect, finished 0.50 cal. armor- piercing bullet. But cannot said that any one operation either machine does more than small part the total work re- quired manufacture dependable, ballistically correct, never-failing, BELOW 0.30-cal. taper presses. Components taken from the body annealing fur- naces are fed into these machines, which form the body taper and neck the case. given its correctly formed profile and point; then the jacket receives its soft lead point-filler, and its hardened tungsten steel armor- piercing core. Jackets, point fill- ers, and cores are automatically hopper-fed the press three different points. Extreme exact- ness required each the steps operation, and the dimen- sions both lead point-filler and steel core must kept within very small tolerances. The second assembly press be- gins work the partially assem- bled bullet where the first press stops, and with its seven stations, the bullet its proper “boat- tail” (tapered) end. Also, the jacket tail must tightly sealed vital war products such ma- chine gun projectiles. Tracer Bullets Tracer bullets are used order show the gunner the direction his fire. These are interspersed with armor piercing bullets that about every fifth bullet traces its course incandescent glow and trace smoke. Jackets are manufactured essentially the same manner for armor piercing bullets. They are heavier wall thickness weight projectile. heavier lead slug forced into the point the bullet add further weight and the remainder the jacket filled with tracing powder packed pressure approxi- mately 70,000 lb. per sq. in. After lubricating the jackets they are forced into dies for the tracer powder charging operation. These dies prevent expansion the jacket they are charged. Operation the machine semi- automatic. measured amount powder dropped through fun- nel into the jacket and then com- pressed. second charge tracer powder followed small charge ignitor powder then placed top the previously com- pressed half-charge and given what call second compres- sion. This fills the jacket its open mouth with solidly packed charge powder. BELOW 0.30 ball bullet assembly press. this press the jackets are fed the first station. The component then transferred the subsequent stations which pointed, the lead core inserted, the heel the bullet coned and based, the completed bullet sized the cor- rect outside diameter, and the cannelure groove knurled which locates the posi- tion the bullet the case. THE IRON AGE, January 1942—33 nce ).50 ent ub- ent ing ass 7 > 4 > difficult ignite the tracer powder and for this reason charge ignitor powder placed the mouth the jacket con- tact with the propelling charge the cartridge case. When the lat- ter burns, the ignitor powder ignited and turn causes burn- ing the tracer charge. The completed bullets are rum- bled sawdust remove excess powder and lubricant, and are then ready for inspection and loading into cartridge cases produce the completed round ammunition. Case Priming Finished cartridge cases are fed into the priming machine hand. This straight-line operation and successive steps automati- cally completes the operation inserting primer each case. this machine the following opertions succession. Primer pocket checked for the presence any foreign matter. vent punched the center the primer pocket through the head the case which carries fire charge smokeless powder. An- other automatic tool checks the presence this vent after which primer inserted the pocket. The next station seats the primer its proper depth few thou- sandths inch below the head the case and the same time BELOW washing and tumbling operations. the manufacture 0.30-cal. bullets, the jackets are washed between operations tumbling barrels. The completed bullet must also cleansed remove lubricating oil, moisture, any foreign matter which may have been deposited the bullet the course its fabrication. 34—THE IRON AGE, 1942 LEFT SERIES turning machines for contrast the ball bullet where the cannelure groove machined the bullet assembly press, this groove turned equipment the armor- means this groove thot the bullet held the mouth the case. “staked” into position fore- ing small amount metal from the cartridge head over the primer cup. This firmly holds the primer its pocket. Liquid water-proof- ing material applied the head the case around primer pre- vent any entrance moisture this point. The cases are next in- spected ani sent the loading operation. Loading have now covered the manu- facture the primed cartridge case, the armor and the tracer bullet. The next operation assem- ble these components the form finished cartridge ready for firing. The loading machine also the straight-line type and fed automatically with primed cases, smokeless powder, and with armor piercing tracer bullets. Cartridge cases move forward through line feeding mechanism and successive stations the correct amount powder added, then the bullet inserted the proper depth, and later firmly held into place crimping the mouth the case into groove the bullet provided for that purpose. The complete cartridge then auto- matically inverted and the tip the bullet immersed paint, which, its color, identifies the type bullet. Black tips are used signify armor piercing bullet and red tips indicate bullets the tracer type. The finished cartridges are care- fully inspected for weight and dimension and are ready for pack- ing. They are packed wooden chests lined with thin metal which ing. This produces package with contents definitely guarded against the entrance moisture any form. > | | Production made airframe manufacturing techniques one the leading independent automobile plants are detailed this article. The material has been partially abstracte from paper presented before the national aircraft production meeting the Society Automotive Engineers last November five engineers the Briggs Mfg. Co., Detroit, and has been amplified, particularly information drawing and forming operations mechanical presses, data since supplied the company and from other sources. ° until the present World War, the volume orders for aircraft was such small quantities that large expendi- standpoint production were not Many orders were placed for one four units, and these airframes were laid out and cut, tried and fitted hand. Today, question how many planes can get into the air the short- est possible space time and the recent past has been possible planes for mass produc- tion. Without attempting de- tract from the achievements the aircraft industry date, engineers the Briggs Mfg. Co. believe they may have come some methods volume manufacturing which will help the whole industry achieve the main goal filling the sky with American airplanes the shortest possible time. The first airframe parts contract ° Briggs received had with the building wings for the observa- tion plane made the Vought- Sikorsky division United Air- craft Corp. Briggs started produc- tion following exactly the pro- cedure used the Bridgeport plant Vought-Sikorsky. work was under way, one the first steps trying gain greater production speed was the breaking down major assemblies into two parts. Next, these assemblies were broken half, giving four major assemblies. This breaking down process was continued until there are now average approxi- mately seven assemblies one compared with procedure the Bridgeport plant. example this the wing tip assembly. begin with, all the parts were being assembled into the fixture, and the holes were laid out hand and drilled. With this method, was not always certain whether the required edge distances were being met. Considerable de- lays were encountered with this manner assembly, and sometimes parts had scraped, resulting more lost time taking them out the fixture and replacing them. Furthermore, doing all the assembling and drilling the jig, not more than two men could put work jig one time. Briggs has revamped the method procedure here completing the parts detail before jigging them completely forming and predrilling them for all rivet hole locations. This plan has enabled the operations broken down the point where the assembly about per cent completed before goes the fixture. The work now done the fixture does not require any layout time, and the operation straightforward and progressive. doing all these preliminary operations outside the jig, possible put more peo- ple work the wing tip assem- bly and spread out the opera- tions such way give more working area. addition, the quality the workmanship has been improved. Fig. shows hand riveting operations wing being performed prior jigging. THE IRON AGE, January 4 for nor ard hen per nto ito- int, the are ing and ich ler- nst Another example revised meth- ods found the manufacture the interbeam assembly. The origi- nal procedure required that all parts assembled, laid out and then taken out the jig and drilled. They were then reassem- bled into the jig, clecoed together; taken out again for burring, dim- pling and fitting, then back into the jig the third time for riveting. This method called for men jig, making Very congested work area, and involved hr. the jig, inordinately long time. Breaking down the assembly was done the case the wing 36—THE IRON AGE, January 1942 tips, Briggs built additional tures for the main beam assembly and also subassembly fixtures for the rib structures. result these changes, only four men are assigned jig and they are pro- ducing beam assembly hr. against men jig who pro- duced beam assembly hr. Another the major holdups production was the fact that lot hand layout work and blind assemblies were encountered. necks, all parts are now prefab- ricated completely before being put into the assembly. The ribs are jigs, welded construction, used for riveting operations fastening the dural skin the ribs the lead- ing edge nose assembly. will explained later, positive action presses and are predrilled allow for clecoing into position. The predrilling, inciden- tally, creates pilot hole for the rivet drill, thereby allowing most the parts clecoed together and riveted the open. This ar- rangement also eliminated many instances complicated blind drill- ing operation with offset drills. Another example this principle the predrilling pilot holes not only all the ribs the wing but also the trailing edge assembly and beam rib assembly, they can used for locating and 3—Ducts for Boe- ing flying fortresses are shown being riveted the plant. More than different sections are used each bomber. With more than 9000 rivets and thousands spot welds, these are among the most plane parts turn out volume. | are into den- the nost ther lany rills. ciple not nbly that and Boe- veted rivets spot out drilling the holes the skin. Fig. shows predrilled ribs set assembly fixture for attaching the skin clecoing and final riveting. Another step toward mass pro- duction methods has been the in- creased use mechanical equip- ment performing such opera- tions riveting. Gang riveters, for example, have been developed whereby five seven rivets are driven one time. the final assemblies, course, most the riveting done with light air hammers the photographs indi- cate. The use hopper feeds for the rivets has also speeded oper- ations the one-shot mechanical riveting machine stands, Fig. Briggs has also studied all con- tour work flat sheets formerly handled with routing machines. This work done stacking number sheets and routing the contour with what amounts modified woodworking shaper, us- ing high speed cutter about 5/16 in. diameter and guide collar contact with wood masonite template. Many these jobs were found lend themselves stamp- ing and forming with mechanical dies, and number original op- erations routers are now re- placed blanking operations. The parts are absolutely uniform, and are completed much shorter time. This brings consideration the prefabrication parts positive action presses, using high test cast iron dies, Fig. be- gin with, ribs were shaped wooden forms and then only the extent that the work stayed straight forward. All reverse flanging and offsetting was being carried with hand hammer forms gen- eral rule. building mechanical dies the automotive type, the parts were completely blanked and formed the dies. The most im- portant parts made this manner are the leading edge ribs, the inter- beam ribs, the trailing edge section and all gussets for reinforcement. This perhaps the first time that conventional forming dies the automotive type have been used for aircraft sheet metal work, although double action hydraulic presses have been used with wood dies faced with metal strips the wearing surfaces the draw ring, etc. Obviously, some new problems have been encountered forming aluminum with conventional draw- ing dies mechanical presses. The character the flow metal the major problem. With steel sheets, possible literally wrap the piece about the descend- ing punch restraining the metal its edges through controlled fric- tion the draw ring. Once the blank diameter has been properly determined that there the right amount metal flow the corners, etc., and the proper hold-down pressure worked out trial and error, steel sheet can the plastic flow. Otherwise the piece will not conform the die shape but will have considerable “spring.” fact, drop ham- mer work, usually cut and try method, allowance made the dimensions the punch and die for spring the work when removed from the die. Such rad- ical die modifications are not eco- nomical with cast iron dies, though 4—One the many double-action crank presses being used Briggs for the first time turn out more than 8000 different aircraft stampings for Vought-Sikorsky wings, Boeing flaps and ducts, and Douglas wings. The press shown rated 1600 tons capacity and the type used ordinarily for forming steel turret tops and other large automotive stampings. drawn successfully with one con- tinuous stroke the press. For intricate shapes, sometimes two three draws are required reach the final shape, but generally stays put. The job not quite simple with aluminum alloy sheets. This material must form itself under pressure and time element in- volved permit the completion feasible with low-cost zinc dies. Many people think aluminum dead soft material, similar property deep-drawing autobody steel. This true only pure aluminum, which not used for aircraft structures. The aluminum alloys, like Alclad, for example, be- have more like high temper spring steel. Apparently, the slight amount copper present dis- THE IRON AGE, January 1942—37 for plant. With Oo 5 5—Loading freight cars complete Vought-Sikorsky outer wing sections Detroit plant. Note the special angle iron racks rigged the box car for pro- tecting the wings shipment. persed throughout the metal such manner form micro- scopic hooks which interefere with the action that normally takes place between slip planes when cold plastic flow occurs. should also remembered that drawing operations, the metal sharp bend tends flow more readily the tension side the sheet than the compression side. some forming work aluminum, quick blow given the tension side “set” the metal. overcome this tendency spring out shape, many oper- ations crank presses has been necessary dwell the press the bottom the stroke for definite period. some deep drawn parts, has been necessary instruct operators take three four pokes the press control button that the slide comes down several increments stroke until the punch bottoms. Then the oper- ator holds the press here for long min. before completing the cycle. deep drawn duct work aluminum has been found that operations cannot done com- pletely double-acting mechanical presses with standard drawing dies. Briggs finds necessary finish these parts hand the present time. However, the com- 38—THE IRON AGE, January 1942 pany installing hydraulic press and expects eliminate hand work through its use. The hydraulic press gives the operator chance adjust the time element more easily and the final pressure the part can applied more slowly and evenly than with the mechanical press, according Briggs engi- neers. expected that this ma- chine will particularly helpful the deeper draws obtaining stampings without cracks flaws and with more uniform thickness drawing operations, course, prevent some thinning the sheet taking place. drawing aluminum alloy sheet, steel sheet, there are difficul- ties caused blanks tearing the corners deep draws. There universal remedy for curing this trouble. Briggs, the problem has been licked through “know how” gained through many years experience autobody work. Briefly, the solution this problem lies combination relatively minor tricks die design, selec- tion the proper contour for the blank, care placing the sheet the die and handling it, and slowness and deliberation oper- ating the press the final stages just before contact made. There has probably been more tearing and cracking aluminum alloy stampings than steel parts— least the early pro- duction airframe score marks the This one the reasons why score marks scratches are not acceptable such sheets for air- craft work and why every care should taken handling the material the plant. Because this factor, also, the dies must made much more smooth than dies used for forming and drawing sheet. Any scratch burr the die critical and must carefully removed polishing. The selection the proper lu- bricants drawing compounds also important factor success- ful aluminum drawing operations these mechanical presses. Briggs uses drawing compound which has vegetable base with neutral mineral oils low quantities. emulsifies hot water 180 deg. and has value 8.3 8.7, putting somewhat the alkaline side, since value repre- sents neutral solution and any value below represents acidity. welding electrodes white with frost. increase productivity aluminum and stainless steel welders, Progressive Welder Co. has developed line refrig- erating units shown here applied the Pro- gressive three-phase aluminum welder. The temperature reduction virtually eliminates point pick-up and vastly reduces shutdown necessary for point dressing, the same time improving weld quality. a. a és § pro- cause why not care the dies steel the tions riggs utral deg. 8.7, aline later frost. minum ressive refrig- Pro- The inates tdown same Heat Treating Cast Tank Hulls CONTRACT last week the Selas Co., Philadelphia, for the design and construction multiple batteries huge direct-fired radiant-heating gas furnaces for continuously treat- ing complete one-piece cast turrets and hulls for the new large (60 ton) and medium (29 ton) Army tanks. Extremely severe re- quirements for absolute heating uniformity and control throughout complex sequential heat treat cycles —despite the great dimensions, weights, and irregularities (in both contour and cross-section) the work—gives this job con- siderable metallurgical interest. Normally insignificant temperature variations would, this new process, produce non-uniform and unacceptable armor. Further com- plications arise connection with continuously conveying through the heating chambers individual cast- ing much 25,000 Pilot installations (themselves giant scale) have for some months been handling small and medium tank hulls for General Steel Castings Co., Eddystone, Pa., and Granite City, Six furnaces (up ft. long) are already pro- ducing—and less than fur- naces (some four times large the biggest date) are involved the new contract. Most the new equipment will incorporated mass-production-lines being set duplicate the biggest-yet 60- ton “mobile fort.” All parts will carried through the final heat treat cycles while suspended alloy hangers from overhead steel beams—a conveying system applied heroic scale, and notable for its fuel economy (only the work itself and small part each 4 hanger passing through the heat- ing and cooling zones). The accompanying drawing shows the magnitude and firing principles one the relatively small “pilot” furnaces which operation for months medium-tank turrets—and the basis which the constructional features and combustion principles the new furnaces were chosen. Some 104 Selas radiant-cup gas burners are distributed over the sidewalls achieve the “planned distribution” heat and high rate “direct heat transfer” essentia: the job. This unit ft. long ft. wide with full-proportioning zoned control. mixed gas and air lb. burner 4,500,000 B.t.u. per hr. Some the other furnaces the battery give precision heat treatments temperatures low 1000 deg. and high 210 deg. THE IRON AGE, January f epre- any ty. 4 2 é How Smooth Should trends these times the intense interest that be- ing shown the condition the surfaces various mechanical parts. appears that the value the slogan: “Save the surface and realized when applied metallic bearing surfaces well wooden siding house. has been less than amazing real- ize the number exacting speci- fications that have been demanded the manufacture given part, yet find that the only one its features that ever wore out has been almost completely nored. Fortunately, interest the quality surface finish def- the up-swing the present time. With the rapid increase the number people interested, should not surprising find the most encouraging HEMINGWAY Chief Metallurgist, International Machine Tool Corp., Elkhart, Ind. ° ° ° that many different opinions are held what constitutes the most efficient type surface for given bearing condition, nor learn that more than one method advocated secure that sur- face. The situation further com- plicated the wide variety lubricating systems, mating metals combinations, etc. Hence, ject which there appears many conflicting views, and that reports and papers, people con- sidered competent, seem en- tirely inconsistent. the pres- ent purpose try point out certain defects very common bearing surfaces, and some their bearing surface was galled because heavy loading and lack lubrication. The “ragged nobs" steel were caused freezing the bearing. ] | i 40—THE IRON AGE, January 1942 detrimental effects, and offer method selection proper sur- face characteristics and surface production, which reduces con- dition confusion one com- parative simplicity. Other articles THE IRON AGE that refer Superfinish, surface finish, surface grinding, and surface finishing and grinding equipment are: “Finish Related Friction Chip Tool,” Sept. 11, 1941, 60; “Optical Flats Mass Pro- duction,” Aug. 28, 1941, 42; “Surface Finish vs. Bearing Capacity,’ Aug. 14, 1941, 38;“Finds Journal Roughness Im- proves Bearing Life,” Aug. 1941, 57; “Superfinish Improved Abrasive Uni- May 15, 1941, 46; “Funda- mentals Grinding Wheel Selection,” July 1940, 38; “Testing Bond Hard- ness Abrasives,” April 24, 1940, 30; “Fundamental Theory Nov. 17, 1939, 79; “Metallurgical As- pects May 1939, 78; “Technique Superfinishing,” Mar. 23, 1939, 50; “The Conception, Develop- ment, Equipment and Measuring Meth- ods for Entirely New Surface Finish- ing Method—Superfinish,” Sept. 1938, 18. The question, “How smooth should surface be?” subject more than one interpretation. many, smoothness has little re- lation the perfection the geometrical shape bearing surface. the finger nail the profilometer says smooth, account taken the fact that surface waviness almost always exists. This condition not usu- ally detected either the eye the profilometer, and longer pitch than the ridges produced grinding turning. Production surface smoothness may include annealing hardened surfaces, caused the heat produced grinding. may also reduce the abrasion, removal of. fragmen- tation surface, caused the violence size producing opera- tions, well abrasion due a 4 q q | F i | | 3 | vy i | =| q | | earing Surface Be? interlocking However, only little speculation should convincing that smooth- ness developed upon wavy sur- face will much less satisfactory than the combination smooth- ness plus perfection surface shape. should immediately evident that uniform oil film thickness greatest importance. Damage mating surfaces can done only through penetration the oil film, with resultant metal metal contact. The difficulties en- countered maintaining ef- ficient oil film are serious enough without contending with waviness, which subjects the film local- ized spots high unit pressure. Yet, surprising find how many times this consideration ignored, even the point em- ploying processes that produce greater smoothness, but the same time neglecting this worse condition, insofar perfection surface shape concerned. The worst result smoothness plus waviness galling, shown Fig. While considerable dif- ference opinion has existed re- garding the exact cause galling, the most competent investigators have come the conclusion that really welding that occurs between the mating bearing met- als. believed that three con- ditions are necessary for hap- pen: (1) The surfaces must ab- solutely clean; (2) they must have certain affinity for one another; and, (3) they must come into sufficiently close contact that they are within the field molecular attraction. Heat not necessary galling action, even though usually present and makes occur more easily. Galling pre- ceded metallic contact, which results the production fric- Defects common bearing surfaces, their detrimen- tal effects, and methods selection proper surface characteristics and surface production are pointed out this article, taking into consideration varying opinions the matter and arriving workable arrangement for commercial practice. ° ° tional heat. This temperature rise causes the metals become more plastic, and thus more able form comparatively large areas contact within the field molecular attraction. The neces- sary affinity, mutual tendency quential degree all the combina- tions bearing metals that have been used, although there con- siderable variation that respect. The extent galling action will depend upon the size the area which the existing pressure can force into metallic contact, while the bearing motion wipes that area absolutely free lubri- cant any other contaminating agent. Ridges, such are pro- duced turning and grinding, shown Fig. easily come into the required conditions for gall- ing, but the areas involved will small, and, though they will numerous, they will immediately 2—Common defects ground surfaces exposed short applica- tion Superfinishing abrasive. Feed marks, chatter marks, grinder ridges and annealing marks are all present. THE IRON AGE, January 7 7 4 | | { a | sh, ind ted | ro- ace ; 14, m- ni- » 30; ” As- 78; 23, on. | break loose. Smooth surface wavi- ness will forced through oil film with somewhat more difficulty, but the galling will correspond- ingly extensive, with greater dam- age being done. smooth surface, high degree geometrical perfection, will almost impos- sible force into metallic con- tact, because the pressure will uniform over the entire bearing area and the oil film will uniform thickness. Complete wip- ing away the oil film will many times more than when waviness exists. long the least trace lubricant per- sists, there will damage, either galling abrasion, be- cause the absence projecting defects. Under conditions rea- sonable lubrication, hard imagine the occurrence damage surfaces real smoothness and perfection shape. Yet, those undesired cases where lubrication completely fails, perfect surfaces can respo