The Iron Age 1938-09-08: Vol 142 Iss 10

.ve- ew- for 000 ne., CAMPBELL ALLISON Publication Office Chestnut and 56th Sts., Philadelphia, Pa. 239 West 39th St. FRITZ FRANK Associate Editors JURASCHEK Consulting Editor Washington Editor Resident District Editors President VAN DEVENTER Editor Managing Editor News Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Editor BINGHAM Pittsburgh Chicago Cleveland Detroit Editorial Correspondents MCINTOSH London, England Cincinnati FRAZAR Boston Hamburg, Germany Milwaukee San Francisco SANDERSON Toronto, Ontario Birmingham Newark, N. J. St. Louis JR. Ruffalo Owned and Published CHILTON COMPANY (Incorporated) New York, N. OFFICERS AND DIRECTORS A. MUSSELMAN, President WILLIAM BARBER, Treasurer BLAIR MOFFETT, Secretary JOUN VAN DEVENTER JULIAN CHASE THOMAS KANE CHARLES BAUR CARROLL BUZBY DIX, Manager Reader Service Member, Audit Bureau of Circulations Member, Associated Business Papers Indexed in the Industrial Arts Index. Published every Thursday. Subscrip- tion Price: United States and Pos- sessions. Mexico, Cuba, $6.00; Can- ada, $8.50; Foreign, $12.00 year. Single copy, 25 cents. Cable Address, ADVERTISING STAFF Emerson Findley, 621 Union Bldg., Cleveland RB. L. Herman, Chilton Bidg., Chestnut & 56th Sts., Philadelphia, Pa. H. K. Hottenstein, 802 Otis Bldg., Chicago H. E. Leonard, 239 W. 39th St., New York Peirce Lewis. 7310 Woodward Ave., Detroit C. H. Ober, 239 W. 39th St., New York W. B. Robinson, 428 Park Bldg., Pittsburgh D. C. Warren, P. 0. Box 81, Hartford, Conn. Editorial and Executive Offices ASA ROUNTREE, JR. Roy EDMONDS FRITZ FRANK, Executive Vice-President FREDERIC STEVENS, JOSEPH HILDRETH, GEORGE EVERIT Vice-President BAUR, General Advertising Manager The Job Never Had Electric Furnace Brazing—Where and Why Use SEPTEMBER 1938 Development Chrysler's Superfinish Steel Mill Pilot Laboratory Opens Range and Size Feature Recent Machine Tool Designs Automotive Industry Current Metal-Working Activity Washington News THE NEWS BRIEF August Pig Production Rate Activity Capital Goods Weekly Ingot Operating Rate Plant Expansion and Equipment Buying New Industrial Literature Products Advertised Just Between Two Index Advertisers Copyright 1938 Chilton Company (Inc.) 108 123 125 148 nes ical ne- las an. for ids : ric ne- of ed. Is- or : st x, y y » it h s MAY sound like heresy some, but Bethle- hem makes magnet steel the open-hearth furnace, well more expensive processes. have done for years and have perfected methods such that the lower-cost open-hearth steel fully meets the requirements for many purposes. The foremost consideration that open-hearth magnet steel offers big advantage cost. Less tangible, but still very important many users magnet steel, the uniformity. Being produced large furnaces, tons finished bar stock are obtained from single heat. 32—THE IRON AGE, September 1938 STEEL xample Bethlehem service users special steels Whatever kind special steel you may use, the chances are that Bethlehem can offer you some- thing worth considering, either service quali- ties, processing properties cost. the Bethlehem organization all metallurgi- cal problems are handled central metal- lurgical division. This provides for applying all the experience obtained contacting all in- dustries the task making the best steel for any particular purpose. unique system provides the means for consistently meet- ing highly specialized requirements. ... THE IRON AGE ... SEPTEMBER 1938 Vol. 142, No. ESTABLISHED Uniontown, Pa. Richard Lee Malone, seven year old farm boy near here, has re- ceived WPA dismissal check for $6.54 for hours work had never done. Three local WPA officials, including Lyell But- termore, head the WPA for Fayette, ever Green and Washington counties, approved the dismissal. The lad’s parents said they felt the seven year old boy, who was listed laborer, should not leave school join the From the News AGE 4 geile: qne gem Electric-Furnace the various established methods fabricating metal assemblies parts has its field economic application. That electric-furnace brazing, comparatively newcomer the list available processes, here indicated Mr. Webber means number actual applications. The article begins comprehensive series which tells how, well where and why, this production brazing process may advantageously employed. Most the data practical nature, and all value effectively applying the process. Articles follow will cover methods holding assemblies together and supporting them the furnace; explanation capillary attraction and wet- ting action; limiting the creep brazing metal; and removing the copper from steel surfaces after brazing. Also, selecting and applying the brazing metal and selecting the flux, needed; and the venting hollow bodies. ment explaining the great strength furnace brazed joints will include data the effects tightness fits and time furnace and the effects heat treat- ment. The furnace brazing cast iron will also discussed and brief article will devoted furnace equipment. The assistance Edwards, Refrigerator Department, and Kelley, Research Laboratory, General Electric Co., and many others who generously contributed make this series articles possible, gratefully acknowledged the author. practically every case has resulted reduction the cost the prod- uct, either manufacture, inspection, the three. Usually, when the furnace- HERE are number well established methods semblies parts which all use most which could not well without. Different methods are used for different products because cer- tain requirements involved. Each par- ticular method has certain ing advantages for its job which other methods cannot give. Usually the method employed the gives the lowest overall cost for mak- ing and servicing the product, all fac- tors considered. Electric-furnace brazing has taken definite place among these various methods fabricating assemblies and forming parts. Where adopted too has been found give certain benefits obtainable other way. most instances its use has 34—THE IRON AGE, September 1938 process has been adopted, has (1) replaced some other method; (2) has been used augment former method, (3) new product has been developed which would have impossible difficult make without the furnace-brazing process. One can best visualize where and how apply electric-furnace brazing actually seeing illustrations duction jobs falling these three groups. Does Not Supplant Other Methods reviewing the various applica- tions follow, the reader asked keep mind that there intention well established meth- ods, nor convey the thought that brazing has come upon the scene replace every modern means fabricating metal assemblies forming parts. The uses elec- brazing overlap these other methods, however, and many cases this process gives benefits ob- tainable other way. the purpose this series articles show where and why furnace brazing has been successful, and give prac- tical suggestions how use it. Automobile and refrigerator manu- facturers, their parts manufactur- ers, make large portion the present list users electric-furnace brazing, perhaps because the domi- nance these industries the metal- working field. them, great strength the joints paramount, but ad- they are attracted the tight- ness, uniformity, and excellent appear- ance The simplicity with which complicated shapes can fabricated, cleanliness the work comes from the braz- ing furnace, and good cost reductions are important advantages. Practically every automobile made today contains several furnace-brazed parts, many brands refrigerators. also holds true for many the lead- ing adding machines, accounting ma- chines, typewriters, radio receiving sets, and sewing ma- chines. Process Described the electric-furnace-brazing proc- ess, assemblies are put together with brazing metal, some such form wire, applied near the joints brazed. The assemblies then passed through electric furnace which reducing atmosphere prevents the metals from oxidizing, frees the metals from any oxides present, and thus prepares the surfaces the parts wetted the molten brazing metal. Then, when the brazing metal n Cc 0 a and Why Use melts, creeps the surfaces the parts and drawn into the joints capillary attraction, and forms alloys with the body metals. Upon transfer the work adjoining controlled- atmosphere cooling the al- when solidifying develop great strength, and the assemblies cool down for them come contact with the outside air without danger discol- wire ring (a) (b) Before After Furnace Brazing between piece steel tubing and steel stamping brazed. the right, after furnace brazing, smooth, neat-appearing fillets copper are evident the extremes the joint, having formed due the surface ten- sion the molten copper. The strong uniform film alloys within the joint also shown. this point in- teresting observe that the strength the bond can controlled pro- ‘Copper alloys IG. Assembly before and after electric furnace brazing. Furnace Brazing 2—Push-rod cover for Buick automobile copper roller-hearth con- veyor-type furnace. ‘ oration due oxidation. this man- ner, the assemblies are delivered from the furnace with strong, tight, joints and clean, bright surfaces. shows the manner which typical assembly prepared for electric-furnace brazing, and how the brazing metal flows through the entire tight joint, forming strong film alloys with the body metal. the left this illustration copper-wire ring shown placed around joint ° ° WEBBER Industrial Department, General Electric Co., Schenectady, ° ° ° viding the necessary area within the joint give the total strength de- Reasons for Using Process Various manufacturing for which electric-furnace brazing has heen substituted are torch brazing, dip brazing, soft soldering sweating, riveting, pinning, welding, machining from solid stock, casting, and forging. brazing has been adopted replace augment such methods, this generally has been there were certain objections the other methods for the job under consideration, among which might found the following: strength—parts work loose service. 2—Non-uniform strength uncer- tain service life. 3—Oxidized faces—subsequent quired. 4—Distortion from localized heat- ing—subsequent straightening machining required. 5—High cost forming—machin- ing, patterns, molds, dies, required. 6—Low production rate—relatively slow manual operations. Where electric-furnace brazing has heen applied, has generally given 3—Over-running clutch cam formerly machined from bar stock but now made two inexpensive parts copper-brazed electric furnaces. THE IRON AGE, September | | one more the following benefits for the reasons cited: Benefits from Electric-furnace Brazing sified, for the sake simplicity, ac- cording the former method used. Result life subassemblies and re- duced service costs. 2—Reduced production costs. 3—Strength high temperatures. 4—Uniform tightness. 5—Little distortion. 6—Excellent appearance. 7—High production &—Flexibility. Great strength and resistance vibration and impact. Savings time, materal, weight, space, rejections, and inspection, Copper used brazing metal, having high melting point. also has good heat conductivity. Uniform distribution brazing metal, through accurate control quantity ap- plied, time, temperature, and furnace at- mosphere. Freedom from localized Clean, bright surfaces and smooth fillets joints. Ability braze many joints each as- sembly one time. High production per operator. Ability braze light parts heavy ones. Unlike metals can joined, such cop- per steel, high-carbon steel steel. best illustrate how these benefits have actually been obtained, specific illustrations follow, showing where the furnace-brazing process been adopted production replace augment other methods. These new uses furnace brazing will clas- RIGHT brazed steel sub- assemblies for cash registers. IRON AGE, September 1938 Formerly Torch Brazed The first example the sub-as- sembly shown Fig. which the push-rod cover for the Buick automo- bile. The joint between the tube and the breather box was formerly torch LEFT 4—Cast iron distributor and steel advance- arm assembly, merly riveted, now furnace brazed for greater strength. brazed, and additional operations were required secure the other parts the assembly place. Now that fur- nace brazing used, all the joints are bonded together one mechanical operation rather than several man. ual operations, and the come from the furnace free from flux and oxides, with clean bright surfaces. Other benefits are improved uniform- ity, greater strength, and lower Formerly Machined From Solid Stock number cases large cost re- ductions have been made tuting the electric-furnace brazing component parts for the machining object from solid stock. The cost setting up, machining, and waste material sometimes appreciable, par- ticularly when compared with the low cost punchings, stampings, screw- machine parts which can assembled together with tubing standard bar- stock and furnace-brazed form in- expensive assemblies having ample strength. Fig. shows over-running clutch cam, copper-brazed electric furnaces the Delco-Remy division Gen- eral Motors. This assembly was form- erly made one piece from bar stock, which required expensive machin- ing operation and waste material. Now made from two pieces with copper wire ring around the joints and brazed mesh-belt fur- naces. The results are uniformly high quality and redyction cost. Drilling operations have been elimi- nated the manufacture steam plate molds for pressing phenolic res- ins, building the molds from plate and bar stock and furnace-braz- ing them, instead boring steam paths through solid blocks steel. this improved method, which has been used several years such companies the National Cash Register Co. and the General Electric Co., the molds are made with greater internal heat-trans- fer area, resulting faster operation and greater output. — 7 Formerly Riveted The distributor bowl and advance arm assembly, Fig. was punched-steel advance arm the cast iron distributor bowl. Under some types heavy duty service, the rivets became loose. Now that the assembly furnace brazed, using brass the brazing metal, has ample strength and long life. Formerly Pinned Seven the leading business-ma- chine manufacturers are now using the brazing process the fabrication sub-assemblies such shown The working parts hookkeeping machines, postage met- typewriters, and the like, operate several million times during their lives, and are consequently subjected se- vere stresses, impacts, and vibration. has been found that electric-furnace sub-assemblies have many times the strength similar fabricated parts made other ways, such pinning riveting; they never work loose, and they save considerable money the reduction both production and service costs. Most the brazing- furnace installations for this class work have paid for themselves within few months time. Comparative strength tests have heen made numerous parts de- termine relative strengths obtained the old and new methods. The data the accompanying chart, Fig. are Note that ultimate strengths typical steel assemblies formerly pinned riveted, now electric-fur- nace brazed with copper, have been increased 287 per cent. This means that the parts have longer life, and they can built with lighter and smaller sections, thus reducing inertia and space requirements. The copper-brazed parts withstand repeated impacts better pinned riveted together. For ex- ample, severe accelerated test which gave 800 blows per min. certain cash register sub-assembly, feather-pinned levers had average life 1,400,000 operations. copper-brazed lever, the test was stopped after 5,300,000 operations there was sign failure. similar accelerated test an- other part gave average life 4,- 500,000 operations for drilled and pin- ned levers. Corresponding parts with copper-brazed joints failed Comparative strength Cash Register Parts Pinned Riveted Electric- Furnace Brazed 1200 Ib ultimate strength Special counter drive Pitman 52% increase Check ejector gear Carrying sector spring bail Switch lock lever Transfer lever shaft Compression rol! shaft bracket No.3 Counter engaging cam 108% Pinned Riveted Brazed Motor bar plate 2100 Ib Counter shifting segment Compression roll shaft bracket No.2 255% 257% Check ejector arm 1200 Ib Printer segment 100 200 | 287%| Osweld and Homen Nations! Cash Reg:ster Co 300 400 Per cent IG. made from the results tests cash register parts, shows the comparative strength pinned riveted vs. electric-furnace brazed parts. 2 — IG. 7—Steel-fin condensing unit made cupped fins telescoped together. This assembly has 729 joints, all copper brazed single trip through continuous furnace. other than the joints after 9,800,000 operations. Cost savings effected use the electric-furnace brazing process run the former costs when drilling and pinning the cash-register assemblies. Actual savings vary from $0.40 $10.00 per hundred pieces. Formerly Soft Soldered Sweated Fig. shows copper-brazed steel fin condenser for refrigerators. The fins are cupped and punched from strip steel and the stampings are then pressed together, forming tubes within themselves. tubing used these units except for the two short con- nectors one end. Condensers this type are built withstand service high temperatures and high internal pressures. Similar units were form- erly made dipping bath soft metal and sweating the joints. Obvi- ously they were limited their ap- plication because the low melting temperature and low strength the bonding metal. The copper-brazed steel-fin condensers have proved very successful and are being used some the largest refrigerator manufacturers. Copper wires are placed inside the tubes during assembly the condensers, and copper plating the strip steel used for the fins provides auxiliary supply brazing metal. The accuracy with which these con- densers can assembled and brazed without leaks amazing. con- denser contains great number joints, sometimes several hundred. For instance, that shown Fig. has 729 joints. production lot where there were 660,000 joints, only leaks were found production test under water with internal air THE IRON AGE, September 1- } 120 Ib 135%. tb m 8—Bushing support for oil cir- cuit breaker, furnace brazed with silver-brazing alloy and flux. pressure 275-300 This can expressed percentage 99.999 per cent good joints. Even those few leaks which were found were patched with torch. This only one number examples where the fur- nace-brazing process gives good uni- formity quality. Welding method metal fabrication, and its uses are continually multiplying. Elec- tric-arc, spot, seam, flash, and projec- tion welding are some the modern methods which have helped im- prove quality, speed production and cut costs. Electric-furnace brazing, though not widely used, goes hand-in-hand with welding for some classes work. Both processes are frequently studied when considering problems, determine which will best meet the many requirements. Some- times product formerly welded can vice versa. shows bushing support used G-E oil circuit breakers, formerly made bronze tubing welded with bronze either steel bronze flange. With the electric-furnace braz- ing, machining required after brazing, exceptionally neat fillet obtained, the sub-assemblies are uniformly high quality, and single unskilled operator can braze several times the quantity formerly welded one man. conservatively estimated that economies from adoption the process paid for the brazing-furnace equipment less than two months’ time. 9—Metal-envelope vacuum tube parts (at left) are copper brazed supplement spot welding. Handy Harman. “Handy” flux paste form applied the wire and the brass tube near the wire. The parts are given wash and bright dip after they leave the furnace. brazing being used supplement spot welding number instances. The metal radio tube, Fig. one example, which eyelets are spot welded into the head- ers and shells. The assemblies are then copper brazed electric furnaces assure vacuum-tight Formerly Cast Forged shows malleable cast-iron clutch-gear bearing retainer which has been replaced furnace-brazed as- sembly for the Buick The mal- IG. clutch-gear bearing retainer. Formerly made from malleable sisting piece steel tubing and stamping. belt pulley made two stampings and one screw machine part and furnace brazed. was pre- viously made from cast iron. brass flange instead bronze. ‘This leable- casting, weighed and effects saving the cost material. when machined, weighed The brazing metal wire ring The furnace-brazed assembly, silver brazing alloy made The bushing supports are now made brass tubing with either steel which replaces it, weighs only 38—THE IRON AGE, September 1938 | > DP e “4 ad 3 & A ae X grt and The dip hich are aces iron has mal- has great strength and low cost. made piece steel tubing and stamping. The pulley, pictured Fig. 11, made from two stampings and screw-machine part; was formerly made from gray-iron casting. addition great strength, lightness, and low cost, the furnace- brazed pulley features ance, thus avoiding the balancing operation formerly necessary with the cast-iron pulley. generators equip- ped with these pulleys operate speeds high 9000 r.p.m., balance important factor. The brazing metal supplied the form ring and four slugs, made from copper wire. track link for track laying vehicles, such tractors, formerly made forgings. The service which these links are put extremely severe. The furnace-brazed assemblies have great strength and are lower cost. One important item the cost reduction the substitution tubing for the members which formerly were drilled. Other methods fabrication have been tried but furnace-brazing has shown itself far superior from the standpoint high strength and formity strength the joints. New Products Through Furnace Brazing brazing has made possible the development number completely new products, which would difficult impracticable make any other way. The automobile heater core shown Fig. 13, made the Novi Equipment Novi, Mich., typical. These heater cores are made steel stampings and tubing, copper brazed together. After brazing, sheet-steel jackets are assembled around the cores provide chamber through which air forced. Exhaust gases which per-brazed track link, for track laying vehicles such trac- tors, subject se- vere service. im- portant saving made substituting tubing for former solid members that required drilling. 13—Core, with part cut away, for automobile hot-air heater. made steel stampings and tubing, and joints are copper brazed. brackets for Buick cars are required withstand severe stresses. screw-machine part pressed into stamping and the assem- bly furnace brazed. pass through the cores, the way from the engine the muffler, give their heat the inner shell. This heat picked the air passing over the shell and then carried into the car for warming purposes. The core has fins inside the shell well outside, and there are shoulders the fins give proper spacing. Copper- brazed joints between the fins and shell give good heat transfer. Those the ends are tight and strong. Quick heat- ing, and delivery heat great quantities, are the outstanding advan- tages this type heater. new Buick furnace-brazed sub- assembly the shock-absorber bracket shown Fig. brackets are fastened the frame support the rear shock absorbers. They success- fully resist severe impacts and bending stresses. Each bracket consists screw-machine part pressed into stamping, with copper-wire ring the joint supplying the brazing metal. (To Carboloy Training Schools Are Resumed “schools” Carboloy Co., conducted the Detroit, since 1937 will continued this fall. The courses are conducted either local Carbo'oy offices the plants Carboloy They consist four six- hour session devoted the practical use Carboloy and are available without charge. Subjects include the economics, design, and application Carboloy tools; and the making single-point, mu!ti-point and form tools. Discussions are supplemented tant design and application features. When time permits, actual shop work brazing tips shanks, grinding, and the salvaging tools made for cer- tain jobs but not completely consumed included. The course adaptable presentation before technical societies, foremen’s and similar groups. Arrangements can made through the company 2995 East Jefferson Avenue, Detroit, through any Car- boloy representative. THE IRON AGE, September 1938—39 ‘ : | — 8 ? 10. accuracy and flat- ness finish accomplished the Superfinisher well illus- trated this offset stack disks, Newton’s Law. the first uses Dr. Ab- bott’s Profilometer was sup- port the contention that when all traces grinding marks are re- brinelling roller bearing races was eliminated. (See first part this article, Sept. issue, page 18.) mirror-like appearance was obtained inside the bearing races the crankshaft the process which actu- ally gave the most perfect finishes. In- stead, there appeared myriad minute scratches. Later develop- ments indicate that when there mirror effect, generally produced the very small helix angle left tool marks. The fallacy consider- ing the bright surface smooth one also demonstrated comparison really smooth surface with any bright-looking mirror-like object. The smoother the two appears al- most dead black. other words, the fewer lines, scratches other defects there are reflect light, the less shiny will the appearance. The experimenters had solved the vital problem measuring surface finish and classifying the results various machirfng methods. under- standing the meaning surface 40—THE IRON AGE, September The Development ° ° WILLIAM SHERMAN Detroit Editor, The lron Age finishing became more clear, the sub- ject took new aspects which led naturally attempts break down the subject surface finish and obtain complete knowledge the fun- damentals involved. the second part the series, which began the Sept. issue, the author pre- sents some fundamental new conceptions and definitions terms relating Superfinishing. Numerous charts summarize the experience the Chrysler Corp. date the use this technique compared with conventional methods finish- ing automotive parts. The third article will deal with measure- ment temperatures metal surfaces, hardness, ductility, strength oil films and other lubricant specifications which must taken into account with this process. ° fo} The data supplied the Profilome- ter exhaustive studies the auto- motive laboratory were used set qualitative definitions and descriptions the surfaces produced turning, grinding, honing and lapping. ad- dition, the Profilometer assisted ma- terially the defining what meant Superfinish. order introduce and describe the different types finish, new nomenclature was developed. Terms which are use result this work include: Micro-inch Scratch pitch Scratch depth Abrasive speed Abrasive pressure Coolant viscosity Surface ductility. These terms are used Fig. (Part Sept. page 20). the fol- paragraphs they are defined with view making clear the dis- tinction between Superfinish four more commonly known machine operations. MICRO-INCH :—Micro-inch term generally used the field sur- a = — “ — 4 face finishing indicate smoothness, SCRATCH PITCH: Scratch pitch the descriptive term used describe the width scratches from the high point one scratch the next scratch. This pitch progres- sively less from turned the lapped finish, but Superfinish does not pos- sess scratch pitch. This the first fundamental difference between Su- perfinish and all other developed sur- faces. SCRATCH DEPTH: Scratch depths produced different finishing methods have The scratches produced turned finish vary far greater degree than those produced other methods, but they usually have uniformity depth regardless whether they are formed single point tool forming tool. The production use turned surfaces (as surfaces) little that space will not devoted further discussion this machining method. The scratch depth grinding honing approximately the same. the scratches are re- moved the base metal Super- finishing, the part will usually re- duced from 0.000015 0.00002 in. diameter; flat surface will duced approximately half this amount. lapped finishes, the depth scratches much less, but the results are dependent upon the ability and ex- perience the man doing the lapping and the time devoted the work. Superfinish develops surface with- out scratches with scratches such minute depth that they are measur- able only micro-inches micro- photography. Experience with Super- finish shows little difference the depth scratches produced abra- sive wheel made 300 grit material compared with 500 grit material, but the scratch pitch much that is, the scratches are wider but not deeper. ABRASIVE speed refers the relative velocities between the abrasive and the metal surface the work. ground finish between 3000 and 8000 ft. per min., normally about 5000. honing, which both rotative and recipro- cating type movement, the abrasive has resultant speed 400 1000 ft. per min. The abrasive speed used producing lapped finishes varies from 100 ft. per min. usually Oscillation One revolution rxij Nine revolutions 7—The proper ratio work speed stone oscillation Superfinishing such that single grit point must never repeat its path along the surface. only translatory motion since the cross travel the lapping stone hardly measurable. Superfinish pro- duced with abrasive speed ft. per min. that produced with extremely low abrasive pressure and low abrasive ABRASIVE ground and honed finishes varies from 200 Ib. per sq. in. whereas Superfinish the pressure usually ounces most, only few pounds. The importance correct pressure will discussed later. FIG. TABLE SHOWING PREFERRED RATIO WORK MOVEMENT SUPER- FINISHING STONE MOVEMENT FOR VARIOUS PARTS Ratio Work rpm Recip- Recip- rocations rocations Part Work min. per min. Pistons 460 240 0.52 Cams 235 5.87 Crankshaft bearings 135 450 3.33 Brake drums 150 550 3.66 Flywheel 175 900 5.14 Tappets 950 750 0.78 COOLANT VISCOSITY :—Here- tofore coolant viscosity has not been primary specification, because the ob- ject using coolant was merely carry away material, prevent heat- ing the tool and work, pre- vent loading the abrasive stones. The coolant used the production turned, ground and honed finishes usually material comparative kero- sene which the viscosity not con- sidered being essential charac- teristic. The peculiarities Super- finish require strict attention this factor. Superfinish, the fluid regarded lubricant rather than coolant. SURFACE DUCTILITY :—It has been demonstrated that much the cutting action the production some fine finishes attributable large degree change the duc- tility the extreme surface the metal, because heat generated the cutting stone tool. shown Fig. the cutting tool turn- ing Operation generates temperature 600 1000 deg. Fahr., making the metal ductile depth 0.010 in. in. Similarly grinding, tem- peratures are 600 800 deg. with the metal ductile depth 0.0005 0.003 in.; honing, temperatures are 100 300 deg., depth affected THE IRON AGE, September Two revolutions Three revolutions 1e- nt as >» > w uw | | | Surface ,micro-inches Time, seconds 0.0001 0.001 in.; and lapping, temperatures range from 100 deg. deg. and the depth from 0.00001 0.0001 in. Superfinish differs that surface temperature raised only negli- gible amount (less than deg.) and the effects are felt only deep 0.00001 in. One the principal claims for dis- tinction between Superfinish other commercial surface finishes BELOW IG. plotted from ac- tual shop records, showing the average number pieces Super- finished per set stones before discarding. Cylinder block main bearings Roughness, micro-inches 3000 4000 5000 Quantity parts per set stones 42—THE IRON AGE, September 1938 LEFT curve showing the rate stock removal micro- inches the Superfin- ishing process indicates that the bulk the high spots are removed the first sec. and that there little economy continuing operation beyond sec. the fact that the low abrasive speed and pressures, coupled with the fects the coolant lubricant, pro- duce surface without developing sur- face heat and hence without change ductility. claimed that the absence scratch pitch and the per- fection finish are directly attribu- table this and the great variety and number 12) motions used Superfinish. The “hunting tooth” principle ap- mental importance attaches the idea that single grit point must never repeat its original path along the sur- face. The required balance between work speed and stone oscillation has Grit stones 8000 300000 ABOVE Profilometer readings after Superfinishing for sec. with va- rious grit stones soft steel, turned ground the initial roughness indicated the upper curve. been worked out experimentally with results shown Fig. Repeated experiments indicate the accuracy Fig. which chart showing the rate stock removal micro-inches various time intervals from the beginning the process un- til the time when stock removal be- comes negligible. Only sec. re- | | | ° ° ° \ 120 180 220 280 320 400 500 600 | Piston Cam main Flywheel et- ro- ur- the w w wn a | w wn Finished ground Finished ground Finished ground | | quired remove the major peaks crests from the scratches the usual turned ground finish. that time, the effectiveness the process begins make use somewhat greater unit pressures the cutting stones the surface. Predictable resu!ts depend techniques. Superfinish requires bal- ance between work speed, oscillation coolant specification, working time, direction stone movement, ini- tial roughness and the stone coarse- ness hardness. Stone grit has important bearing the finish that achieved. Fig. illustrated the effects sec. application Superfinish with variety stones ranging from 120 400 grit. Also shown are the effects using 400 600 grit stones ground surface. The 30-sec. limit has been chosen arbitrari!y representa- tive the maximum time used for Superfinish for production economy. Records Stone Wear the cost standpoint, the rec- ord stone wear Chrysler ex- ceedingly favorable, apparently cause the stone, light contact with part after part, thereby kept shape. The fluid used effec- tive the point insuring against excessive stone wear while aiding the RIGHT IG. 12—Valve stems are Superfinished this machine, using disk type stone the vertical head. The valve stems are revolved their own centers, the opposite direction from the finishing wheel, means cork driving disk, co-axial with the wheel spindle. cutting process. Records have been kept stone wear and replacement when Superfinishing number im- portant automotive parts, and the re- sults are charted Fig. 11. the valve stem Superfinish more than 300,000 pieces have been These particular parts with two large stone disks trated the photograph Fig. 12. All the other parts are finished with small rectangular stones shown diagrams and photographs the ac- tual operations. The lowest output per LEFT and Pro- filometer readings various parts from the rough the final Superfinish. set stones the crankshaft, which has average 260. Follow- ing order are cylinder block main bearings, 300; cam bearings, 800; piston, 1650; flywheel, 1800; tap- pets, 8000; and brake drums, 9800. Each these parts comes the Superfinisher with different initial surface. The brake drums, shown Fig. 13, are bored with 0.022 in. feed, giving initial surface mea- surement 110 micro-in. This repre- sents important departure from previous practice when brake drums were turned with 0.005 in. feed. THE IRON AGE, September 1938—43 NAME ea Cylinder ir- q h - head 2 | This gave initial surface about micro-in. roughness. Rougher Initial Surface Desirable The production department changed this boring operation provide faster feed, when was learned that Superfinish was best applied rela- tively rough surface get the quick- est operation for final surfacing. addition, the faster feeding with the boring tool gives more accurate cut with less loading the tool and re- sultant chatter out-of-round. The final finish the brake drum held micro-in., providing greater fric- tional contact between the drum and lining, better braking, pedal pressure and less brake wear. This typical the miscellaneous im- provement the product effected Cylinder wall Piston as fitted in rough cylinder bore Note how crest Scratches are worn off PART NAME After 500 miles run-in conjunction with the use Superfin- Also indicates economy op- eration. all other parts, similar improvements are indicated chart. diagrammatic form, the effects piston wear are illustrated Fig. 14, where the former rough surface piston and wall were permitted wear during the break-in period the automobile engine. Now, the piston previously rough-ground micro- in., Superfinished micro-in. av- erage roughness, and bores are given similar finish. The effects are said virtual elimina- tion the piston and wall wear dur- ing the break-in period. this wear amounted 0.002 0.003 in. net the diameters. Moreover, there graphic proof 14—Superfin- ishing and cylinder wall re- sults surface comparable that obtained 2000 miles run-in, start- ing with convention- ally finished and rough ground istons. After 2000 miles run-in Note how scratches have worn down basic metal similar *> a lopped surfore Micro-inch readings that the quality finish can main- weeks, the variation has been shown negligible, whether the allowable average roughness was set ten millionths inch only two millionths the case piston pins (Fig. 15). has been the practice during the development Superfinish make sample tests everyday all the vari- ous parts which the process was ap- plied. portable Profilometer use for this work and record all readings maintained. The pro- duction record shown herewith com- piled from the cumulative readings With any wearing surface auto- mobiles objects for application Superfinish, the physical task applying the process has been gigantic one. Each part sented peculiar problems, but solutions have been reached adherence the fundamentals learned study the crankshaft and bearing races machin- ing process. The mechanical division Chrysler Corp. worked close con- junction with the Foster Machine Co., Elkhart, Ind., the design equip- ment. The tappet, for instance, pre- sented the problem Superfinishing Crankshaft main bearings 6.40 5.42 6.22 7.56 6.36 5.15 6.33 6.20 5.99 Crankshaft main bearings 6.14 6.15 5.12 6.66 5.52 644 537 Records Truck-Crankshaft main bearings 6.18 6.57 5.93 6.48 6.62 6.48 6.62 Profilometer 6.49 taken various automotive parts over period 5.00 4.91 4.66 4.82 weeks indicate Cylinder block allowable surface roughness are negli- gible, even for pis- 5.97 5.97 5.87 ton pins for which the millionths inch. Piston 2.65 2.2 2.52 Connecting 44—THE IRON AGE, September 1938 Eigh ain- riod the set ston the ari- ap- ro- ible ical een ons the the valve tappet finishing machine has heads arranged circle, but only two them are shown this close-up view. motor units made the Inde- pendent Pneumatic Tool Co. drive the Norton cup- shaped stones, rotating them eccentrically, while the tappets are slowly re- volved their own cen- ters. The entire machine head also rotates, that the operator can load and unload from one position. Automatic cycle control provides for raising and lowering the finishing heads and clamping and driving the tappets. tainment the necessary stone motion and oscillations adjusted produce the required finish was the use cup-shaped stones mounted off center. The parts are carried Armco Brings Out New Galvanized Roofing NEW kind galvanized rooting with patented spring-pressure lap and other features has been an- nounced the American Rolling Mill Middletown, Ohio. known Armco galvanized roofing, and said storm-proof, weather-tight, and easily installed. View before nailing the patented spring- Pressure lap that features Armco Galvan- ized roofing. 4 table-like fixture, heads up, which ro- tates, carrying the part from loading station unloading. Meanwhile, the cup-shaped stones descend from above, contacting the parts. The work re- costs more than ordinary metal roofing per square applied. The new roofing available three grades metal—copper-bearing stee!, open-hearth steel and ARMCO ingot iron. When placed position and nailed down, the sections are held firmly together with spring tension three points. Drainage channels and siphon break- ers are built-in features. The pressure lap the lower end each sheet gives added protection, providing pressure-sealed contact the end laps and effective water stop. The sections nest snugly to- gether. Because the spring pressure seam, “Seal-Krimp” must laid one row width time, starting the eaves and working towards the ridge. volves 950 r.p.m. while mounted 3/32 in. off center turns 750 r.p.m. the offset direction, maintain- ing 3/16-in. oscillation. The equip- ment and setup are shown Fig. 16. Roofing accessories available with include adjustable ridge roll, made two pieces fit any ordinary roof pitch without bending lengthwise fit V’s either side the ridge. Other accessories available are end wall flashing and gambrel joints. spring-pressure lap after nailing. The upright legs are forced downward and outward. Pressure the flanges against the lower lapped section. They abut the bead one side, while the opposite side the bead forced down and into the up- turned flange. This holds the sections to- gether firmly. THE IRON AGE, September On- ip- ‘ \t- er on ive ns ce : Opens Unique outstanding feature the pilot plant this open hearth furnace with capacity 1500 the recuperative rather than the regenerative type with unusual type burner. Some features this fur- nace may applicable those used commercial production. 46—THE IRON AGE, September 1938 iot Mill-Laboratory Unit CAMPBELL Pittsburgh Editor, The Age the gap between re- search and everyday production merging theory with com- mercial practice best methods and procedures used the new Jones Laughlin Steel Corp. pilot-mill development units oratory which were this week Pittsburgh. Main features this new approach research series small scale steel mill units addition the usual laboratory facilities found research departments. Thorough investigation steel making processes ranks im- portance with the research and devel- opment steel products. Technique followed the staff studies and experiments, such that control maintained from the mak- ing steel through the forming and the actual testing. Commer- cial practice simulated the lab- oratory the use small open hearth furnace, electric are fur- nace, induction furnace, steam hammer, and two small rolling mills, one which capable duplicating blooming mill practice. addition these experimental but practical proc- esses, series physical tests in- volving the use recently developed, well standard, testing equipment. normal research practice, great many ideas are originated and given considerable thought and effort. How- ever, the philosophy behind this new approach product and process de- velopment advocates the concentra- | a a re- com- the the lab- scale ation im- evel- that mak- mer- lab- open fur- team nills, iting in- rreat new de- tion activity those ideas which give promise becoming commercial- applicable. Projects are soundly investigated and developed from both theoretical and practical standpoint before being certified the regular mill production department that they are commercially feasible. Projects are assigned each divi- sion the laboratory the basis the general fields science activ- such metallurgy, physical metal- lurgy, development pilot plant, ma- chine shop and testing, library and patent division, and the service clerical division. The entire research and develop- ment division under the direction Graham, general metallurgist the company, who facilitates the co- ordination the division’s work with mill. This coordination insures that the attention the which under the supervision Work, directed toward prob- lems practical value. Much the equipment the pilot mill units and laboratory, ing utilized carrying out research investigations, is, itself, under constant scrutiny for further development. This feature especially applicable the small experimental open hearth and special testing equipment. The laboratory building proper has heen designed more for utility than for appearance, and the construction has provided for additions when neces- sary. Offices, libraries, machine shop and testing laboratories surround the steel mill unit. experimental open hearth with unusual type burner re- cuperative, not regenerative. Regular open hearth practice used prac- tically every step steel manufacture this small one-way fired open hearth unit. The furnace was designed and built Jones Laughlin engineers with the thought mind that some features the construction and oper- ation would applicable commer- cial production stee!. Special controls this furnace are provided for air temperature, gas vol- ume, air volume, furnace pressure, roof temperature, and stack draft. successful application this recuper- ative type open hearth furnace commercial practice could long Way toward reducing melting time and hence, steel making costs. Special tests slags and steel pro- duction are also conducted with the use capacity electric arc induction furnace provided for other RESEARCH AND DEVELOPMENT LABORATORY INVENTORY EQUIPMENT CENTRAL SHOP Machine Capacity Ajax-Northrup Open hearth furnace ......... Recuperative, and original de- sign. Rolling mill (large) .......... in. in. square........ in. mill. Rolling mill (small) ........ in. in. square ...... 2-high in. mill. Surface combustion furnace ...3 ft. ft. hearth, 2400 deg. maximum temperature ...... Billet heating. 4 ie. = 23 ie. hearth... Chemical bench and equipment, for both metal and slag analysis determinations, located the central shop. Burrell high temperature furnace for making carbon analysis steel combustion one the interesting pieces equipment used the work. MACHINE SHOP South Bend lathe.......... South Bend lathe.......... in. swing. Cincinnati milling machine ....2-L universal. Delta woodsaw and jointer ....8 in. saw, in. jointer. Standard pedestal grinder ..... in. wheels (2) Laidlaw metal bandsaw ...... in. billet capacity. Marvel highspeed hacksaw ....9 in. billet capacity. Portable grinder in. wheels (2). PHYSICAL TESTING LABORATORY Foeppl-Pertz damping capacity friction metal method free vibrations. Bakelite mounting press ...... in. diameter mounting ...... Clear and opaque mountings for metallurgical specimens. ...... specimens. Carpenter torsion impact ma- in. diameter specimen ..... Rockwell hardness tester ...... Hoskins electric furnace ...... Type FD204, amp.... Small muffle furnace. Hoskins electric furnace ......Type FD104, 5.46 amp. ...... Small pot furnace. Rockwell dilatometer .......... Model not over in. square in. long... Krouse high speed fatique ma- Up to 0.125 in. diameter ...... For wire specimens. Repeated torsion fatigue ma- Fatigue machine with corrosion Fatigue machine .............. tensile machine ns 8000 to 40,000-Ib. capacity, ad- justable range ............ Tinius Olsen torsion .......... Izod and Charpy Combined Izod Charpy ma- chine. METALLOGRAPHIC LABORATORY Zeiss metallographic microscope.2250 diameters (camera 8 x in.) 4000 diameters....With polarized light and dark field attachments. Bausch and Lomb microscope..2250 diameters .............. With assorted lenses .......... 35 mm. negative. Eastman motion picture assorted lenses .......... Eastman portrait camera ..... Bell Howell motion picture Spencer delineascope ......... Dark room equipment ........ Washers, driers, etc. For all types film and plate. Fisher metallographic polishers.8 in. wheel, variable Eastman professional printer ..11 x 14 im. ...............055- THE IRON AGE, September hes accurately controlled experiments steel making. 18-in. cupola used later conjunction with small bessemer converter which constructed, part the laboratory equipment. gas-fired muffle provides individual soaking pit for the smaller ingots. Ingots the pilot mill range from 185 Ib. 900 Ib., the latter size being slabbing type. many cases the actual ingots made the experimen- tal mill can taken rolling mills for processing while other instances the production made the rolling mills located the labora- tory. steam hammer used times for reducing the experimental ingots previous ro!ling. Products the pilot plant units are sent well equipped machine shop where they are prepared for testing. Considerable research the develop- ment proper test pieces carried regularly the machine shop. 48—THE IRON AGE, September 1938 LEFT Teeming miniature ingots the pilot plant. These weigh from and are broken down one the two rolling mills. BELOW 3—This minia- mill used reduce bars into convenient sizes for test speci- mens. fired heating furnace, and 500 steam hammer are used this work. re q gots from Ib. ken the The physical laboratory, addition the usual tensile, impact and fatigue tests, includes variety compara- tively recently developed machinery. stiffness tester for sheets and strip. damping capacity tester, dilato- meter, and other special complete the physical laboratory. redesigned facilitate special inves- tigations. complete tory with Zeiss microscope and cam- era, dark room, photographic room and motion picture camera able. Another useful unit the develop- ment laboratory research library comprised over 600 books and technical publications well ous association proceedings covering pure sciences the production fin- ished products. This service avail- able not only the research staff but all those who are interested. The staff the research and devel- opment division constant cooper- ation with the regular mill metallur- gical department and portion the work involving projects under study, carried out the mill proper. units were established primar