The Iron Age 1944-12-07: Vol 154 Iss 23

VAN President and Directer BAUR Vice-President General Manager ° and Advertising Offices East 42nd New York 17, N.Y., U.S.A. Johnson, Market Research Mgr. Hayes, Production Manager. Baur, Typography and Layout Business Managers New York New York 100 East 42nd St. 100 East 42nd ROBERT BLAIR GIBBS Cleveland Pittsburgh 1016 Guardian Bidg. Park Bidg. Bid 1134 Otis PEIRCE LEWIS WARREN Detroit Hartford Conn. RAYMOND KAY Los Angeles 2420 Cheremoya Ave. ° Owned and Published CHILTON COMPANY Executive Offices Chestnut and Séth Philadelphia 39, Pa., U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH Vice-President GEORGE GRIFFITHS 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 Member, Audit Bureau Circulations Member, Associated Business ° indexed the Industrial Arts Index. Pub- every Thursday. Subscription Price North America, South America and Possessions, $8; Foreign, $15 year. Single Copy, cents. Vol. 154, No. Editorial Technical Articles Combining Stretch and Pressure Contour 18-8 Stainless Modified for Formability Chromium Inoculants Developed for Cast Iron ° ° Features ° ° News and Markets Powder Metallurgy 126 United Air Lines Leave York Consolidated Line 130 Rail Passenger Traffic High Octanes for Aviation 142 Machine Tool Market Developments. Non-Ferrous Metals News and 160-161 Iron and Steel Scrap News and 162-163 Comparison Prices Week and 164 Finished Iron and Steel, Steel 165 Warehouse, Semi-Finished, Tool Steel Prices Steel Pipe, Tubing, Wire Products, Pig Iron and Coke Stainless Steel and Ferroalloy — ay - ; YOUR PRODUCT built better with WELDED STEEL CONSTRUCTION The business Mahon not con- cerned solely with fabricating vast volume bases, frames, parts and fittings for hundreds diversified products. highly important phase our work analyzing the prod- ucts those manufacturers who may not entirely familiar with the many advantages WELDED steel plate construction light weight greater Feel free use this service whenever you will. 58—THE IRON AGE, December 1944 Sand blast finishing but one many oper ations required this Diesel Generator Set Base. Mahon facilities are capable handling any character steel plate any volume. strength smoother appearance reduction scrap. staff experi- enced engineers always ready study your product—and advise you intelligently and sincerely switching WELDED construction would advisable and line with greater economy. They will even assist you any redesigning required. | Cau 3 f { Fabricators Machine Bases and Frames and Many Welded Plate Products f ESTABLISHED ° ° 1944 ° President ond Director ond Genera! DIX Manager, Reader Service Associate Editors WINTERS ALBIN ANTHONY JACK HIGHT BARMASEL Editorial SCHIEN WILLIAMS VAN CAMP MILLER LLOYD Pittsburgh Park Bidg. POST Chicago Bidg. MOFFETT DONALD BROWNE EUGENE HARDY Washington Press Bidg. Cleveland 1016 Guardian 7310 Woodward Ave. OSGOOD MURDOCK San Francisco Market St. €ditorial Correspondents ROBERT DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham JAMES DOUGLAS Seattle | Durable remember that famed old “one hoss shay,” the vehicle that went pieces all once and all over when its time service was up. Wheels and body, shafts, axles and bearings all disintegrated simultaneously mutual void obsolescence. From the standpoint some modern designers, this accomplish- ment having had nothing left over when the period service was finished was the attainment the ultimate engineering. One manu- facturer told quite seriously some time ago that ball and roller bearings used automobiles were too long lived relation the life the vehicles they equipped. Judging the “graveyards” find scattered throughout the country, there are other parts and accessories equally over-durable. Some students, well economic professors, would take issue with this thought downgrading the life expectancy components that they parallel the life span the product itself. They say that the opposite principle the correct one; namely, improve the wearing quality the weaker parts increase the expectable term ser- vice the product whole. From the standpoint sound eco- nomics, they say, our aim “more goods for more people”, then making what have last longer will give the necessary purchasing power buy greater variety commodities. There are other economists equal standing who say that prac- tice this policy extending the life span products would cause the stagnation industry and trade have come know them. They point the yearly model policy the automobile industry and ask where the five million cars year output would have been, had there not been annual style and design changes that made people want turn their vehicles after twelve months service. what would happen the millinery business women would willing wear the same hat for six years instead six months. must confess that the answer these questions beyond power. Perhaps both policies have their merits applied their special provinces. When comes rebuilding the postwar world, the rebuilding the destroyed homes and industrial plants abroad and the new build- ing homes and plants our own country, look and hope for the acceptance the principle durability. want low cost housing but not shoddy houses. want modern design our machine tools and manufacturing equipment but want also the durability and ser- viceability that will enable them stand and take it, and take long enough return good profit their cost. far our own metal working industry concerned, not believe that there will any change the objective serviceability product, whatever may be. And serviceability takes into consideration the factor durability. When forget strive make things last well, well serve well, will heading down the wrong road. § hing Diesel ities are ? Its Powder Dry Stored deep the holds Allied fighting ships are water-tight boxes—each containing 100 lbs. powder. These powder boxes stand hard usage, stack easily and keep precious condition for instant use our fighting men. Thousands have been made Inland hot-rolled pickled and oiled sheets. They are welded construction, and galvan- ized inside and outside for full protection. The opening the top sealed with gasket drawn tight hand screw and spider. The bodies are formed from 16-ga. sheets. ta the Navy Keeps Tops and bottoms are made 13-ga. sheets. The tops are formed four operations—blank and punch opening, deep draw 2-34” and emboss opening, corners and roll back edges. The excellent working qualities Inland sheets help speed production and save time and materials. When Victory ours, the modern Inland continuous sheet and strip mills, which now are producing full capacity for the war effort, will again making sheet and strip for hundreds peacetime products. INLAND STEEL COMPANY Sales Offices: Cincinnati Detroit Kansas City Milwaukee New York St.Louis St. Paul Longitudinal bod seams are securely clamped before resist. ance welding. Powder boxes must keep fighting ship’s dry. bod News December 1944 Since acquisition control New York investment banking interests, solidada, whose main plant Mexico City, has been shopping for two electric furnaces and blooming mill. These would complement its ton open Piedras Negras, just across the Texas border, take advantage Texas scrap. blast furnace Monclava, operated Altos Hornos, also promises Texas scrap consumer. Principal Mexican operation, however, continues Acero Mexico Monterrey. Permanente Metals Corp.'s plans produce ferrochrome now depend the authority for $100,000 dust collector installation. new process, silicon will used reduce iron content low grade chrome ore. Captured German airfields show that they carried camouflage incredible during the four-year occupancy France and Belgium. and other tions, often remote from the landing field, follow the lines local closely that even from the ground they are indistinguishable from other farm and houses the countryside. Each house exactly fitted airplane. They really are houses, with central heating and interior comforts for the air and ground crew who lived them along with their aircraft. Intense anti-aircraft fire has always been major German defense weapon. These installations not take nearly the manpower that would normally expected. Banks weapons are loaded mechanically, and fire controlled automatically radar, which has been developed very high efficiency. Manpower stringency great that the Luftwaffe Command has replaced male bers observation posts with 19-year old girls the Alps, Southern and Central Germany. With only few weeks' training aircraft recognition, these girls are unable frequently distinguish between friendly and unfriendly aircraft. several recent instances, targets inside the Reich have been attacked before warning received. Some observers believe that when the mines the Saar Basin and the Ruhr are captured that important underground aircraft factories will found among them. Howe ever, these deep workings are not suitable for parts construction, and even number months ago some mines were selected and conversion work actually there evidence that the plan was abandoned. However: Numerous salt mines and deep quarries Germany have undoubtedly converted aircraft plants, with armored concrete roofs even more substantial than those employed over submarine pens. The pumping and ventilation problems for such| underground factories would not nearly formidable would the case for Ruhr mines. The German jet-propelled aircraft, 262 and 280, are undoubtedly made underground factories absolutely secure from bombing, for these airplanes Germany's last hope the air. Many the jet plants also are distributed among mountain valleys Austria, and soon will threatened the Russian drive. The British bomb was originally made three cylindrical containers fixed like sausages. now has been fully streamlined and has well blast effect. Used against German submarine pens, bomb this type was found have ft. steel and concrete roof. Recently, similar bomb falling deck the Tirpitz finished off. Copper supplies are increasing rapidly despite WPB moves relieve civilian uses. Newly authorized items civilian consumption represent nificant tonnages, meanwhile, domestic premium payments and foreign imports 15c. per lb. holds encouraging postwar market prospects that are attempting capitalize. The Reynolds Metals Co. has been developing anodized coatings for their products. | | q { must Par | q / 7 | q q 4 { 4 Manufacturing Rifle Parts three years, the substitution broaching for milling oper- ations the Garand semi-automatic has resulted de- crease per cent the cost manufacture and per cent the number manhours required. complete analysis compara- tive capital costs for equal production given. the first part five-part after discussing general considerations, the author describes the broach tooling for the heaviest part the rifle, the receiver. The principles broaching economy illustrated these particular examples apply equally well any high produc- tion work parts comparable weight. Springfield Armory, Spring- field, Mass., re- leased the infor- mation that Col. George Woody, Commanding Offi- cer, witnessed the stamping the 3,000,000th serial number the re- ceiver the semi-automatic rifle. Production records the Armory show that the output the (semi-automatic rifle M1) the last five years approached the total all small arms made the arsenal the 145 years from 1794 1939, which reached total 3,822,743 guns various types before the rifle went into mass production, thus setting production record unequalled the 150 years its existence. There have been times Armory history when the output shoulder arms entire year did not reach that the rifle single day the peak Armory production, which increased more than 100,000 month. Actually, the semi-automatic “U. Rifle, Cal. M1”, generally known the Garand, has been produc- tion since 1937, but the first two years production output was limit- due the conventional procedure manufacture. Late 1937, how- ever, program was inaugurated retool this rifle, utilizing the most modern machine tools processes which would permit rapid expansion the event emer- gency. Records show that the adop- tion the most modern methods and particularly the broad use IRON AGE, December 1944 Head Engineer, Production Engineering Department, Springfield Armory, Spring- decrease field, Mass. machines resulted per cent the cost manufac- turing the Gar- and rifle three years, and reduction per cent the number manhours required only year and half ago fabri- cate each rifle. not generally known that these successful results were obtained due the extensive use surface broaching machines and this arti- cle the manufacture few typical components for the Garand rifle will reviewed, with special emphasis the use broaching for machining, showing the savings invest- ment, manpower, and floor space. early 1935 the writer began study utilizing surface broach- ing machines for manufacturing small rifle parts. With the assistance the Cincinnati Milling Machine Co., the first study was completed and preliminary processes were laid out. The basic principal adopted that time was avoid using hand milling and hand profiling, and improve upon existing power milling methods using broaching machines, but only they were the most economical and made possible the high production de- sired. For over two years this material was dead filed until the Garand rifle was adopted the Army the Rifle, Cal. M1. The urgent need for exceptionally large quantities this rifle the shortest possible time prompted the restudy the originally proposed broaching methods. order appreciate the amount saving derived manpower, capi- tal investment, and floor space, adopting the broaching method lieu milling, where this method ap- view the fundamental advantages over milling and later sub- stantiate them illustrating specific operations several component parts for the semi-automatic rifle that were originally milled but later retooled for broaching. (1) Surface broaching fast, efficient method machining with cutting time usually shorter than any other method producing the same results. One the reasons for this that while work held stationary the multiplicity cutting teeth pass across the workpiece, each removing only one chip the rate anywhere from times that possible with the milling process, most generally used for the same type work. the time required complete the cut does not vary much, does mill- ing, due the variation the length the cut. For instance, the length cut were in., and due the change the design the component, the length the cut were increased milling machine will practically doubled; however, were broach- ing operation, the time required for this cut will slightly. substantiate this statement let consider the factors that control the time required perform the broaching operation, speed ram travel and the length stroke. Suppose this hypotheti- cal the speed was ft. per min. and the stroke was originally in. for the in. cut. Assuming that the material this case remained the same and the length cut only was doubled, the cutting speed will re- main the same, but the stroke length the ram travels will creased. known rule that the stroke the machine determined several elements, some which is m al re r 0 a rc ° s N ( ‘ ATTERY small duplex broaching machines installed mory for machining parts for the Gar- and semi-automatic rifle. this plant there are duplex broaching machines, ranging capacity making this the largest broaching installation under one roof the world. remain constant, such allowance in. for approach inserts, other words, the space between the work and the first roughing tooth, and also in. for overtravel and clearance the fixture. There are two variable elements that enter into the length stroke; first, length cut, and second, length broach in- serts, which vary directly with amount Since the amount stock re- moved remains the same, pitch increases with increase the product chip thickness times length cut, therefore total length broach inserts will longer proportion increase pitch, which our hypothetical case will about in. Adding this the in. in- crease length cut the total in- requiring in. stroke broach the redesigned piece work. Translating this into the time ele- ment, the original cutting time would min. and the new time, 1/6 min. Using duplex broaching ma- chine the operator loads and unloads one fixture while cut being made the other, and since the majority cases removing the work from the fixture, cleaning the locating points, and loading and clamping the work usually requires between and sec., obvious from the foregoing that doubling the length cut prac- tically does not affect the net produc- tion per hour obtainable from the broaching machine. permits machining several taneously, regardless their rela- tionship, long all elements the broached surfaces remain parallel with the axis the broach holder and there are the path the broached surfaces. ing, the number surfaces machined are limited due complex- ity cutters and undercuts, which often make compound cuts impossible. Simple layout usually indicates such condition, that is, limitatior com- bining several milling cuts one, forcing process engineer resolve the job into several milling cuts. (4) Surface broaching permits ma- chining components with much great- accuracy and better finish one pass than does milling because rough- ing and semi-finish broach teeth re- move the bulk material and finish- ing teeth always remove only light chip from the broached surfaces and consequently can maintain closer tol- erances and finer finish. (5) The chip problem milling very serious matter, especially the plants where incentive com- though time allowed rate setting, the operator does not pay enough at- tention chip disposal, resulting overflow coolant, clogging clamp- ing arrangements, chips getting into spring actuating jack supports, all which are undesirable conditions and result inaccurate inefficient production well loss time clearing the fixture prior reload- ing. surface broaching, the other hand, this problem practically does not exist. properly designed, broach inserts, carry the chips past the work below the fixture and the coolant washes them off the bottom the tank. making the fixtures that there place for chips lodge, cleaning time not required. (6) permits rapid expansion production since the initial output production per hour broaching machines very high. the same token, broaching limited high production work. (7) Broaching equipment occupies less floor space compared with mill- ing machines producing the same number parts, and performing the same cuts fairly large daily output. (8) The cost perishatle per unit produced surface broach- ing much lower due the long life the broaching tool. One the reasons for this low cutting speed, which hardly ever exceeds ft. per min. steel, which less than half the speeds used milling with high speed steel cutters. Since impact vary the square the velocity, the destructive effect the tooth striking the work much less with the broaching tool. According ex- periments conducted years ago, was shown that when the factor heat eliminated, the wear milling cutter varies directly the number impacts the cutting tooth upon the work and that the thickness the chip has appreciable effect. Usually each tooth broaching strikes the work just once the start the cut, whereas the teeth milling cutter strike many times before the cut completed. conventional milling the chip starts from zero thickness, resulting abrasive action which breaks down the cutting edge. The broaching tooth, the other hand, always starts with positive thickness chip and does not suffer the same abrasive action. The longer broach tool life also due the better conductivity the heat. THE IRON AGE, December 1944—63 finish machined. weighs over the rough. This can explained the stronger and heavier tooth shape broach tool, which usually has rake from deg. deg. and clearance angle from deg. deg. contrary- wise, because the milling cutter tooth actually forced into the work ma- terial, means that has sharp- ened relatively high clearance angle from deg. deg. and addition has backed off small land. This weakens the cutting edge and materially reduces the heat conductivity. (9) Broaching tools have long life because the roughing teeth re- move the metal rather thick chips and finishing teeth the finishing taking light chips. The former stand considerable punishment, while the latter, encountering scale removing small amounts stock, last long before requiring resharpening. (10) Easier application coolant important advantage the broaching method. centrifugal action, milling cutter revolving be- tween and 100 ft. per min. throws coolant away from the point where most needed.. broaching tool coolant can directed exactly where wanted and actually flows be- tween the tooth spaces under slight pressure, thereby helping separate the from the tool and giving more satisfactory cooling. selecting the method manu- facture the cost per piece always the predominant consideration; there- 64—THE IRON AGE, December 1944 fore the process engineer his study analyzes all factors which add the final cost the article. knows the number parts produced given period time. the choice between milling and broaching, his next step estimate the number milling machines and number would require meet the production schedule and the cost milling machines, fixtures, and cutting tools necessary pro- duce the required number com- ponents given time. Similar estimates are made for the same pro- duction broaching. this write the equation: where labor cost produce re- quired number pieces using milling machines factor all special milling fix- tures, arbors, and other items required set and operate mill- ing machines for this particular article all milling cutters neces- sary produce required number parts all milling machines necessary schedule =Percentage factor, including amortization, taxes, depreciation and carrying charges ap- plied this article labor cost produce re- quired number pieces using broaching machines all fixtures, broach hold- ers and other items necessary broach this article that cannot used for other parts all broach inserts neces- sary produce required num- manufacturing plants where charged overhead expense, the items and should eliminated from the equation. the first part the equation greater than equal the second part evident that broaching the correct method adopt. Before proceeding with estimating the cost broaching vs. milling perhaps advisable consult field engineer who well versed broach- ing and its limitations, and who can render advice whether not the design parts make them suit- able for broaching. One the limit- ing factors the amount stock removed one pass. Another the condition that the work cannot have any obstruction the plane the surface broached, since the broaching tool usually quite long and must pass completely across the work. addition, the work must strong enough withstand the stresses set broaching. broaching, the rapid travel tools sets stresses greater amount than milling. The ability the part stand these stresses, and thus allow broaching advantageous, depends not only the design the broached part and the material made of, but great extent the design the holding fixture (including proper shape supporting blocks against the broaching pressure), the arrange- ment the cutting tools and the de- sign the tools. far support the work concerned proper fixture for almost any work can designed experienced broach- ing engineer; essential, however, that the work rigidly held the fixture avoid vibration and spring- ing while the cut being taken. particular Broach Fixtures and Tools designing broaching fixtures should kept mind that they should quick-acting, since the cut- ting time relatively short and the operator required unload and load the fixture during the cutting time duplex type machines order obtain maximum utilization mec tab tive ing tic machine time. Clamps may the cam, screw, weighted type, they may electrically, hydraulically, pneumatically operated. Automatic mechanical fixtures, actuated the movement the swivel retracting table, are also used. The main objec- tive always achieve quick load- ing and unloading time with mini- mum physical effort the opera- tor, since likely repeat this process several hundred times per hour, including the handling parts which may weigh each. There fast rule for design and arrangement broaching tools. Each case must studied problem itself. However, pitch and chip per tooth are governed the length the work, amount stock re- moved, and the finish desired. The principle shear cutting may used surface broaches gives better finish and eliminates vibra- tion. Springfield Armory shear angles some surface broaches high deg. are used. broach- ing forgings and castings where there are usually wide fluctuations the amount stock removal, the first tooth the broach must bear the brunt removing the entire excess; therefore rule the first tooth, called the bumper tooth, usually made much thicker Regardless the length the broach insert required remove given amount metal one pass, the rule has been adopted not make inserts longer than in., even would require making broach insert four five pieces, each following the other. This rule was adopted for sev- eral reasons, wit: (1) more economical for the manufacturer broach inserts handle small pieces would less expensive lose small FRONT END SUPPORTING BLOCK broach insert than large one. Difficulty might encountered heat treatment the broach in- sert might lost grinding. (2) less expensive for users broach inserts replace small section than one very long solid broach insert. The loss might teeth mistakes made resharp- ening setting. addition, many cases possible utilize broach inserts more efficiently moving finishing inserts place the preceding one when can- not used any more finishing broach insert. This stepping down nomical gain when the taper gib adjustment not sufficient. Since each broaching machine and broach insert manufacturer has de- veloped its own formula for calcu- lating the pull capacity the ma- chine required for each individual job and has also developed empirical tables slide rules for calculating “safe chip room,” tooth depth and shape, pitch, face angle, land and back angle, the discussion broach insert design will limited the following: The cross-sectional area the chip the product the length cut chip times the thickness the chip before being cut, amount material removed one tooth. When steel chip rolled into spiral form usually occupies about times the area its actual cross- sectional area. order provide sufficient chip space the gullet must correspondingly larger contain that chip without packing. The Cin- cinnati Milling Machine Co. has set down the relationship that the area the gullet should times the cross-sectional area the chip when broaching and has prepared the data pitch and chip thickness re- lationship shown below: Chip Thickness Pitch Steel Length n. 0.0022 0.0031 0.0042 0.0055 0.007 0.0104 0.0145 0.0168 0.0193 0.033 0.0495 0.0673 0.088 For other details broach insert tooth design the reader referred the chapter broach insert de- sert design the book entitled “Broaches and Broaching,” published Broaching Tool Institute. broaching rifle parts Spring- field Armory all except one component come the broaching machines forging, trimmed, scale removed and heat treated for good machinability. Since each component part subject other machining operations, such milling, profiling, drilling, ream- ing, thread milling, was necessary 2—The first machining operation the receiver Oper. 10, straddle broaching the forging lengthwise. ° ° ° Stock THE IRON AGE, December 1944—65 re- not ere eld se ist LOCATING RAIL select the range hardness that would give satisfactory broaching and would not detr mental the tool life other chining operations. From experience was found the best result obtainable broach- ing was have the work heat treated have hardness reading 250-265 Brinell. This hardness too high for other operations, and was found that hardness range between and 200 Brinell tory for all machining operations. Every lot forgings inspected the size and hardness before released for machining. Inspection with gages the size absolutely because forgings have FRONT END SUPPORTING 66—THE IRON AGE, December 1944 3—(Upper sketch) Oper. broach crosswise the front and rear magazine legs receiver. (Lower sketch) Oper. consists finish broaching the underside and the front and rear the magazine legs and the front end the receiver. The fixtures for both operations are similar. (Fixture for Oper. 12B shown.) DOWN HOLDING FORGING AGAINST non-uniformity beyond the allowable limits. order apprecite what saving was obtained Springfield Armory methods wherever this method was practical let review several component parts the Garand rifle. will neces- sary review the typical parts and compare the results with similar data assuming milling machines were used. Operations Receiver The largest and most difficult part manufacture the receiver, shown Fig. the upper view forg- ing and the lower view finished component requires over machining operations. The HOOK CLAMP APPLIED ‘ Gage Gage 3000 0%” 0.860 72.905 40008 first eight cuts are broaching opera- tions and work held hydraulically operated fixtures. This feature very important since the forging weighs over lb. and handled from 180 700 times one hour some machines where four different cuts are made. was necessary there- fore reduce physical fatigue minimum relieving the operator entirely effort clamp the com- ponent. This change from the fixture design with hand operated, mechanical clamping arrangement hydraulically operated clamping per- mitted increasing production approxi- mater per cent some cases. Every fixture equipped with micro- switches and electrical contacts in- terlocked with main operating cir- 4—Oper. consists broaching right side, rail and locating pads the receiver. tio UNDERSIDE SUPPORTING BLOCK APPLIED H,. cuit which prevents the operation the machine the clamps are open the forging not properly located. The first machining operation illustrated Fig. and the op- eration sheet known “Operation 10-stradde broach lengthwise.” The actuating taper plugs which enter the front cavity B-B and rear cavity A-A. This permits proper distribu- tion stock removal. Forging placed into fixture against positive stop point marked and held with two hydraulically operated clamps applied points marked and ADJUSTABLE FRONT STOP front and rear forging, ing against hardened block the fixture with surfaces indicated with letter The material 8620 steel, with stock remove the right side 0.234 in. maximum and the left side, 0.143 in. The accuracy required 0.003-0.004 in. with fine grade machine finish. Since the roughing broaches start cut narrow trimmed surfaces was ad- visable remove heavy chip 0.007 in. per tooth the beginning the cut, and gradually decrease the chip per tooth the cut widens that the finishing teeth remove chip only 0.001-0.0005 in. thick. This operation performed the left ram 15-ton duplex surface broaching machine, having in. stroke, forward and return speed 21.6 ft. per min. Total standard time per piece, including personal allowance, inspection, cleaning up, punching time card, adjust- ment the fixture and broach in- serts sec., which usually re- duced the operator piecework per cent, and gives produc- tion least pieces per hr. The right side table equipped with double type fixture holding two components while the ram with two mounted broach holders pass the work, taking two cuts, passes, illustrated Fig. The first pass known “Operation 12A, rough broach crosswise front and rear magazine legs,” after which the forg- ing removed and placed into the next fixture and second pass made. This known “Operation 12B, finish broach underside and front and rear, magazine legs and front (See lower sketch, Fig. 3.) UNDERSIDE SUPPORTING BLOCK The forging located both fix- tures identically, that is, part rests its left side the fixture located lengthwise from the cavity marked “stop,” with the in-and-out location controlled stop against the rail marked Two hydraulically op- erated clamps hold the forging the fixture, one holding the component down applying pressure the surface indicated letter and another clamp keeping the forging against the locating rail applying pressure point Due the draft the forging the amount stock removed runs high 0.201 in.; however, since the broach inserts those cases begin cut the apex narrow point the draft, the chip load per tooth starts out 0.006 in. and gradually reduced 0.002 in. the width cut begins increase leaving stock amounting only 0.001-0.0005 in. per tooth removed with the finishing teeth. Allowable tolerances this op- eration are quite liberal and there less than limit 0.004 in. Broaching Procedure Since these two cuts are made the down stroke the right hand side ram the same 15-ton duplex broaching machine the same speed, the total standard time per piece the same and the minimum produc- tion per hour also the same, that pieces. The broaching procedure and handling the forgings this machine for the three operations follows: Assuming that all fix- tures are loaded, the operator pushes the starting button, initiating the 5—Oper. 116 consists form broaching the rear end the receiver. cycle. First, the left hand table brings the fixture with forging into broaching position and the left ram begins its stroke, moving down until the finishing broach inserts pass the work. The ram remains the down position while the left ram table auto- matically swivels back. Then the op- erator presses the starting button again, but this time the right ram table brings the double fixture into broaching position and the right hand ram carrying broach inserts begins descend, taking two cuts described above. same time the ieft hand ram ascending and the operator removes the broached forging from the left hand fixture and replaces with new one. The operation the machine stops after each stroke, which allows the operator sufficient time unload and load the fixtures safety. Since there intermediate grinding op- eration after the first broaching cut the left hand fixture there supply ground forgings hand for the second broaching. After the THE IRON AGE, December a, J n- r- FY, VERTICAL AND SUPPORTING BAR operator presses the starting button which sends the left hand ram down, begins unload the fixture mounted the right hand table, first removing the forging with the finish performed and transferring the forging that was just roughly broached into its place. then loads ground forging into the fixture for the roughing cut. repeating this procedure with each stroke the machine, one forging with three broaching operations performed produced with each cycle the ma- chine. cycle comprises one ram stroke down and return. The forg- ings are brought the operator conveyor and taken down for grinding after the first broaching cut made the left hand fixture. Following grinding they are brought back the same man- ner. After the third broaching com- pleted the forgings are placed SIDE 68—THE IRON AGE, December overhead conveyor that carries par- tially broached parts the next broaching machine, which 10-ton, in. stroke duplex surface broaching machine. This machine equipped with pair identical fixtures, broach holders, and broach inserts perform the operation known “Operation 11A, broach right side, rail and locating pads,” trated Fig. The component located the fixture the left side and supported lengthwise the front end marked “stop.” One hook type clamp holds the component with pres- sure applied the point marked against hardened blocks contacting underside surfaces marked and the second clamp applied the right side forcing the part against the left side the fixture. The maxi- mum stock removed from the top the forging for locating pads 0.102 in. and only. 0.015 in. from the right side. Since the broaches UNDERSIDE SUPPORTING BAR 6—On the same table which the fixture shown Fig. mounted this second fixture for performing Oper. rough broaching both sides the legs. SIDE CLAMP immediately begin cutting broad sur- faces, the chip load per tooth for the roughing broaches starts out 0.002 in., gradually decreasing 0.0005 in. chip removed the finishing broaches order maintain ac- within 0.002 in. Since each ram performs the with each stroke, one component broached with each stroke and hourly production, with all allowances taken into consideration, least 190 pieces. Duplex Machines Favored The next four broaching operations are performed single 15-ton, stroke duplex surface broaching machine. Each ram equipped with two fixtures each holding one com- ponent, that each stroke ram two cuts are made. the left hand table are mounted two fixtures. The first fixture holds the component while operation known “Operation Use ~Q003 7—The fixture for performing Oper. 13B shown and for Oper. 13C (Fig. are both mounted the right hand table the same machine carrying the fixtures shown Figs. and the left-hand table. Oper. 13B involves finish broaching the sides the magazine legs. 116, per: The clar gra 0475-00 Ss ae LONG CLAMP APPLIED Locate angles, must centralized Gage from 8—Oper. consists finish broaching the ends the magazine legs the receiver. SIDE LOCATING PLATES VERTICAL SUPPORTING BAR 116, form broach rear end” ing teeth remove only 0.001 in. marked letter Two clamps performed, illustrated Fig. per tooth. The second fixture holds are applied hold the component The component supported the component while operation known rigidly, one right, indicated. front end and undersides and “Operation rough broach both letter and the other two clamped against the left side. The sides magazine legs” shown marked the top the maximum stock removed performed. The receiver. The maximum stock 0.166 in. with chip load per tooth supported the rear end its removed 0.191 in. and since the 0.007 in. roughing broaches, legs indicated “support” teeth strike fairly wide gradually decreasing that finish- located undersides and left side, (CONTINUED PAGE 156) TABLE Comparative Broaching vs. Milling Operations Receiver Rifle BROACHING MILLING Number Number Number Number Machines Operators Machines Operators Description Required Required Required Required Operation Produce Produce Operation Produce Produce Machine Net Pleces 1000 Pieces 1000 Machine Net 1000 1000 Used Per Per Hr. Per Hr. Used Per Hr. Per Hr. Per Op. 15-66 in. Op. 4-36 in. broach lengthwise Foot-Burt mill sides Cincinnati duplex Hydromatic surface miller broaching machine Op. 12A—Rough Same Op. 5—Mill 4-36 in. broach crosswise magazine Cincinnati front and rear crosswise Hydromatic magazine legs miller broach underside underside surface miller and front and rear rear end magazine legs and front end underside eurface miller front end right side, rail, and Foot-Burt step right side locatirg pads duplex Hydromatic locating pads top miller Op. 116—Form ton In. Op. 116—Form No, 1224 broach rear end Foot-Burt mill rear end Milwaukee miller Op. 13A—Rough Op. No. 3-24 broach sides mill sides Cincinnati magazine legs lengthwise and ends Hydromatic magazine legs Op. Same magazine mill sides miller lengthwise and erds Op. magazine legs broach ends magazine legs THE IRON AGE, December 2, i Ss i- a 5. n surface broaching machine The potentialities tool steel welding first became evident when emergency repairs tools were made meet war schedules. Data here shows how closely the characteristics the weld deposit conform those all basic types tool steel. NDER the stress war production schedules, many shops turned despera- tion welding make emergency repairs broken tools and dies, and found that welding could done suc- cessfully hardened tool stee!s. New applications, new highly developed electrodes, new wrinkles all accordance with few principles, will this process one that will have tremendous possibilities the tool room both for repairing tools and dies and for the composite fabrication new ones. Tool steel welding specialized that will increasingly important grams. Just mild steel welding electrode deposits weld metal, tool steel welding elec- trode will deposit tool steel weld metal any one several basic types, such hot work tool steel, oil hard- ening tool steel, high speed tool steel, etc. The weld deposit will have the characteristics that are typical each type and may tempered, drawn, annealed rehardened, the same any tool steel its classifi- should made here between tool steels and hard facing materials. There tendency re- gard them being the same since there some overlapping few applications. The fundamental dif- ference is, however, that hard facing materials are not usually heat treat- able but rely inherent changeable hardness tool steels may annealed, rehardened and tempered any desired combina- tion hardness and toughness. the fields application widely separated but the uses hard facing alloys tool tipping have led little confusion these two grotps materials. order take full advantage the arc welding process the con- struction and repair high speed steel tools and dies, one shou!d have all the information that available both the welding electrode and the steel used. Steel suppliers have abundance data their tool and die materials, and these should consulted and compared with simi- lar data the welding electrode. surprisingly close match heat treat- ing and working conditions between weld and tool may made cedures indicated this comparison method are followed. both feasible and possible weld hardened tool and die mate- rials without losing hardness the tool and without leaving embrit- tempering curves all typical high speed steels lie within the shaded area. The red curve the weld deposit tempered from ROCKWELL HARDNESS 500 600 800 900 1000 1100 IRON AGE, December 1944 ° ° ° FOOTE Manager, Tool Steel Division, Alloy Rods Co., York, Pa. tled zone fusion between weld and base material, recently developed the proper type are used. Preheating the tool die before welding very essential eliminat- ing this hard fusion area under the weld and also retarding the rapid quench the weld deposit from the welding heat. The weld itself air hardened from the welding heat and preheating tends slow the cool- ing through the critical range. Types Steel Reviewed High Speed Steel: The accompany- ing tempering curve (Fig. shows that the high speed steel weld de- posit has the secondary hardness that typical all high speed steels, and would indicate that hardening result are welding similar conventional hardening. Tempering after welding necessary and should done according this curve the weld deposit meet whatever working condition desired. Double tempering the weld deposit may used gain about two points hardness over single temper the same temperature and holding time, and follows recent theories mar- tempering high speed steels. way comparison, notice that the hardness shown Fig. the same that shown Fig. yet was double tempered for total hr. plus whereas Fig. was single tempered for hr. The hardnesses Rockwell would indicate that the weld deposits both had been almost completely de-austenitized somewhat dif- ferent handling. How high speed tool would look after having been repaired are welding shown Fig. The base may considered the tool, having hardness 64.9 Rockwell before welding. After preheating 500 deg. the tool was then welded and tempered for hr. 1025 deg. The 66.2 tool Roe for mos line with qual than sam prob long the tools seem —th weal The low shrir these spee ture: used for is to are whie 1.00 CS DOUBLE TEMPER y The weld now shows hardness 66.2 Rockwell while the body the tool slightly 64.3 Rockwell This ideal condition for welded tool. The weld shows acicular martensite structure with most solution. The fusion line blends well and has very few eu- areas. The base metal normal acicular martensite structure with carbides. From comparison these photo- micrographs can reasonably con- clude that the cutting and qualities the weld will better than those the base material the same analysis because the higher solution carbides the weld. This probably explains conductivity and high coefficient expansion could produce upset con- dition hot working tool this material. The air hardening steels can readily welded care used pre- heat very slowly and uniformly and fatigue checks and cracks are com- pletely removed before welding. The tempering curve, Fig. shows that the weld deposit has the second- ary hardness typical the type and advisable that the weld material should not tempered between 600 and 800 deg. This electrode may used for other applications involving friction —such lathe centers, ceriterless 2—Photomicrograph high speed grinder rests, wear pads, deep draw- longer life welded tools against steel weld showing the value double ing dies, ete., and especially use- the conventionally hardened forged tempering against single tempering ful for making composite dies. tools that are oil quenched. for twice the time the case Fig. Oil Hardening Steels: great The ability the weld deposit many oil hardening steels lend them- selves repair welding with the non-shrink electrode. The weld de- posit this electrode non-shrink, but may used repair other oil hardening alloys since the performance expressed the tempering curve, Fig. very near- the same. Most the tool alloys this group have very low draw range and preheating before weld- ing care must used avoid heat- ing over the low temperature the draw range (200-400 deg. F.). Welding should done slowly these steels and stopped whenever the overall temperature the work has reached the maximum draw tempera- ture (400 deg.). pyrometer should used frequently, especially when the repair large. This non-shrink type oil harden- ing steel widely used the die retain hardness elevated tempera- tures shown Table The air hardening steels are often used for cold cutting dies, and also for applications where abrasive wear met. Many burnishing tools are made these types which range from per cent Cr— 1.00 per cent Cr—2.5 Wear resistance (and also fatigueability) —the high chrome type having more wear resistance (but also will fatigue easier) than the lower chrome type. The dimensional change types during hardening extremely low being even less than the non- shrink oil hardening steels. While these types are one kind high speed steel, they should not used where much heat encountered be- cause the combination low thermal A speed . typical high speed steel, tempered 1000 deg. left the center, fusion line and right, base metal. Magni- fication THE IRON AGE, December TABLE Hot Hardness Arcaloy High Speed Steel Weld Deposit Welded Double Tempered 1000 Deg. Hardness—Rockwell After Test Specimen After Min. 1000 deg. deg. 1200 deg. TABLE Hot Hardness Arcaloy Hot Work Weld Deposit Welded— Not Tempered Hardness—Rockwell Temperature After After After Test Cold Specimen Min. Min. Before Reached 1000 deg. 1200 deg. TABLE Selection Materials for Composite Dies Tool Die Function Cold cutting (light duty) (heavy duty in.) Type Tool Steel Electrodes Base Water hardening SAE 1040-1050- Oil hardening 1335 High speed Oil hardening-400 deg. temper Air hardening-900 deg. temper SAE 1050-3100- 4100 series SAE 3100-4100 series SAE 1050 SAE 4150 SAE 3150 SAE 3100-4100 SAE 1050 Hot cutting Work hardening (some) Hot work High speed Hot work Work hardening Hot forming Hot heading Hot extruding Hot forging Cold forming and heading Air hardening-900 deg. temper Cold forging Work hardening (non-magnetic) Abrasive wear Water hardening Air hardening-400 deg. temper High speed-1050 deg. temper Oil hardening SAE 1050 Air hardening: Punch 900 deg. temper Die 440 deg. temper SAE 4150 Water hardening (light cutting) Oil hardening-400 deg. temper SAE 1050 SAE 1050-4150 Punching Shearing (see cutting) Air hardening-900 deg. temper Air hardening-400 deg. temper Work hardening (non-magnetic) High speed High speed Drawing Cold extruding High speed cutting SAE 1050 72—THE IRON AGE, December shop because its low movement hardening and its fine cold cutting qualities. Many low alloy tap steels may repaired with this electrode with improvement tool perform- ance and very close match heat treatment. The photomicrographs show little finer tempered structure the weld deposit than the base metal, which the ideal condition for welded tool Though not desired show picture what not do, effort stress the importance keeping the overall heat repaired unit under the draw temperature, there included here photomicrograph weld made without regard keeping the heat down. Fig. shows that the weld deposit, while thoroughly tem- pered, has typical course cast struc- ture, and effect has not been quenched fast enough. This due excess heat condition during welding. The hardness much too low both weld and base. welded die, this would show soft spot around the repaired area. Naturally this avoided, and can small electrodes are used and welding interrupted the die approaches its maximum draw tem- perature. temperature 700 deg. has little effect. Work Hardening Steels: The weld deposit made the work hardening type electrode not tool steel but fills need repairing fabricating many dies. The deposit austenitic and can used advantage drawing dies where pickup avoided. This material Rock- well welded, and will increase with cold working maximum 46-50 Rockwell will withstand severe impact and can used cold hot heading dies. Being un- many hot work applications where lower hardnesses are suitable. the deposit cold worked the upper machinability range, will harde