The Iron Age 1943-01-28: Vol 151 Iss 4

JAN 1943 Inc. WARREN, OHIO HEAVY PLATE HI-SPEED SHEET AND TIN MILL SHEAR LINES ING TIN PLATE EQUIPMENT WILSON TUBE ANNEALING WEAN VACUUM CUP SHEET AND PLATE LIFTERS HALLDEN MACHINE CO. CONN. OWN, OHIO STRIP PICKLING, MING, AND LINES billets, astern base 4 of, | THE IRON under act of March 1879. hed every Thursday the CHILTON CO. (INC.). $& ve arly it North Entered second class matter November 1932, the Post Office ol. Americ: and South America, Foreign $15. No. 4. gurnace has muffle; ynits heat directly onto work. This plus the ample input results very recovery the prazing fast prazing and good economically JANUARY 28, 1943 VOL. 151, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager te) ° Editorial Associate News Editor, JAMES Associate Editors Art Editor, WINTERS Editorial Assistants BUTTERS Technical Articles Resident District Editors Production Slender Parts Swiss Type Automatics Redesigned Fuse Adaptor Saves Time and Editorial Correspondents Silica and Semi-Silica Toronto, Louis New Equipment: Plant Service Seattle ° ° DIX, Manager, Reader Service Features ° ° Robert Blair, 621 Union Cleveland Hottenstein, 1012 Otis Bid Chicago Robinson 428 Park Bldg., Pittsburgh Warren, Box 81, Hartford, Conn. Johnson, Market Research Mor. Hayes, Production Manager. Baur, Typography and Layout. ° ° ° News and Markets Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub- lished every Thursday. Subscription Price Cable Address Machine Tool Activity CHILTON COMPANY (Incorporated) Iron and Steel Scrap 112 Executive Editorial and Chestnut and Sts. East 42nd St. Finished Steel Prices 115 Philadelphia, Pa. New York, U.S.A OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President EVERIT TERHUNE, Vice-President Index Advertisers Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALS Copyright, 1943, by Chilton Company (Ine.) This Week in... | | | . | ° ° 4 ¢ = Post Office SWITCH STEELS Assurance Jominy End-Quench Hardenability Testing Ryerson Lab. All Alloy Steels are tested before they are accepted for stock and tests are conducted assure accuracy sults. This data passed with each shipment. Alloys Ryerson Stocks Write for New Booklet New Technical data including heat treat- Representative stocks Steels are avail- ment response—is available (National able Ryerson for prompt shipment. Turn- Emergency Steels. Ryerson tests all Steels over rapid; withdrawals are heavy, but new stock. information furnished stocks are constantly being received. Ryerson with each shipment that particular engineers and metallurgists will gladly answer Steel. Thus, users can choose which the any question you may have and help you get lean-alloy steels will best replace the steels started with Steels. high alloy content previously used. Jominy End-Quench Hardenability Tests, JOSEPH RYERSON SON, INC. CINCINNATI DETROIT CLEVELAND method determining heat treatment re- BUFFALO BOSTON PHILADELPHIA sponse. How this test made, the results JERSEY CITY obtained, and ‘how interpret hardenability terms tensile strength, yield point, elon- gation, and reduction area, are clearly told HANDBOOK STEELS recent Ryerson publication Steels. New, complete, authoritative! Com- Copies are write your piled Ryerson. you are adapt- ing Steels your production and nearby Ryerson plant. copy, ask for one today! = “OStpy ONS Son j = =) Testing are tested and check curacy customers e FJANUARY 28, 1943 ESTABLISHED 1855 "One Million Workers UPPOSE you read your newspaper tomorrow morning that mil- lion men and women workers had gone out strike. That every mechanic, laborer and white collar employee the city Detroit and vicinity had dropped his tools and gone sit-down strike that every man and woman all the plants our great steel industry had taken indefinite French leave from their war jobs. What headline that would make! And what hole would make too our industrial war program. that happened would not take the authorities more than five minutes something about it. The people would rise wrath and demand the ones responsible that they cease immediately soldiering for Hitler and Hirohito. would cause thousand times more public re- sentment than the recent walk out few thousand coal miners. such situation existed and union leadership was strong enough say Uncle Sam: “Leave us; these men and women who shirking their patriotic duty shall back work once, What boost that would give union leadership public opinion. Such situation actually exists effect, believe not. More than million workers American industry are out sit downs every work- ing day the year except possibly pay day. These sit downs un- noticed because they are not labeled strikes. They are not called out adjust grievances and they are not contemplated one industry community but spread over our entire industrial structure. They are the result individual absenteeism. Collectively they our war program more harm and our Axis adversaries more good than any strike that pos- sibly could take place. Absenteeism moderate estimate averages fully per cent our daily total labor American industry. certain percentage absenteeism normal and unavoidable. People catch colds; have attend funerals, face other emergency situ- ations where staying away from work legitimate. But certainly the legitimate factor would not exceed five per cent. Anything above that sabotage. What being done about it? The employer cannot much about it. fires man for absenteeism, likely meet eventually with the War Labor Board and most employers want stay far away from that body possible. think the responsibility union leader- ship handle this situation. They have been given plenty power it. They can revoke union card; the employer cannot. They can recommend extreme cases that the malingerer reclassified for draft; the employer cannot. Here chance for union leadership public service that will resound its credit and offset some the rising tide public resent- ment power without responsibility. six months intelligent leadership directed this end could add eight million man hours per day our war production. And that would nearly solve the manpower shortage. ny + ig — é ° ail- son wer | Our Metallurgists Are Ready Help You these critical days, when quick and specific results are imperative, America must make full use the best possesses expert training and ex- perience. That why urge you take advan- tage the knowledge Inland metallurgists. They are men with many years’ experience fine steelmaking, applying steel products varied and intricate design, and the best methods fabrication. They are accustomed tackling dif- ficult jobs. Their record success remarkable. Inland metallu rgists not confine their work lab- oratories. They have had many years experience with the problems metal working plants. They work with steel and make steel work for others. Possibly you suspect there better faster way producing parts for your products. Perhaps you have fabrication problem that Looking ahead, you may thinking about the redesign products and development new ducts that will needed for future markets. Whatever your need, our metallurgical department ready and anxious serve you. YA Detroit, 4 & § “SR ‘aa ” A \ ag i b q 3 SS A N NX 3 BS PW 3 N ¥ 4 rc rience They ers. way you esome. the rtment ° ° FRANK OLIVER Technical Editor, AGE ° ° tween Swiss type automatic and turret type single spin- dle automatic screw machine that the stock not only rotated give the “speed” function, but also fed axially during the cut provide the longitudinal component the feed. The single point turn- ing and forming tools are provided with infeed only, and order provide for four five tools single work plane, they are dis- posed radially the upper half semicircle, Fig. Accurate di- mensional control aided using centerless ground stock and feeding through bushing whose outer face just few thousandths inch away from the plane the cutting tools. end working at- tachment provides drilling and threading one diam- eter. The work fed through the guide bushing the tools slid- ing headstock which contains the collet chuck and all movements the headstock and tools are con- trolled cams. Such set-up does not necessitate the use any broad form tools. combination. headstock and tool movements, any ASICALLY, the difference be- taper form can produced without form tools, simply vary- ing the radial infeed particular tool with reference the stock feed. All tool holders are provided with micrometer the individual adjustment all tools both radially and paral- lel the axis the werk. Usually single point tools are employed and because the unique design the machine, there al- the back shoulder work,and even back recessing which can done. Many parts, including corporating pivot can Production Slender Parts Swiss Automatics Originally developed for the clock and watch manu- facturing trade Switzerland, the Americanized Swiss- type precision finding new place this country because the impetus given the demand for small, finely finished parts the war program. This type single spindle machine particularly adapted the turning pinion blanks, shafts and small slender parts used clocks, electric meters, radio equipment, striker pins, detonators, fuse elements and precision instruments for aircraft, artillery and naval use. finished the cut-off, thereby eliminating the need for second operations. Fig. gives idea the class work handled the Swiss type machines. Most them represent long, slender pieces used instruments various kinds. Capacities 5/32 In. made Switzerland, stand- ard capacity these machines was from 4mm. (5/32 in.) mm. 1/16 in.). The most popular size exported was mm. (9/32 in.). this country, 5/32, 7/16 and in. capacity machines ing built. The machines show best advantage competitively smaller diameter work com- plicated nature. Fig. for ex- ample, shows small stainless steel instrument pinion produced one set-up five-tool in. Wick- man machine. With its seven dif- ferent diameters and five “necks,” accomplish one set-up tur- ret type machine. Actually this piece was being turned out previ- single spindle automatic and then performing the additional opera- tions separate set-ups pre- cision bench lathes. Time min. sec. per piece the Wickman machine looks high first glance when one thinking terms simple screw machine work, but compared the time taken the bench lathes, represents tre- mendous gain output per hour. The principal advantages the small 5/32 in. machine are higher spindle speeds and smailer working parts which permit ‘closer running tolerances and, therefore, produce components greater limits ac- curacy. Also, much easier set and handle the smaller ma- chine small work. Tool setting and other adjustments may made with greater delicacy and dimen- sional stability maintained be- ing able use the proper speeds and feeds the smaller parts produced. Whereas the machine per- mits maximum turning length in. more, the machine with in. chuck capacity used only for the production parts THE IRON AGE, January 28, 1943—27 = S 9/16 in. long. These are the ex- tremely small, highly accurate parts required the manufacture pre- cision instruments, watches, etc. The actual forms produced, many cases, can clearly per- only when the parts are placed under magnifying glass. with the larger machine, com- ponents which have pivot points, back shoulders, multiple diameters, tapers, bevels, etc., may duced single operation. The accuracy, finish and concentricity the finished parts are such high degree that secondary machin- ing operations are practically elim- inated. Long Cycles Whereas not unusual turn out small screw machine products the former, cycle times the Swiss machine range from sec. average time min. should understood, however, that much this work taking relatively long time difficult nature and either could not handled all would involve second-operation work. With these machines for ex- ample, possible turn piece several inches long from stock size only 0.025 in. and such piece might have section one end only 0.012 in. diameter and in. long. demonstration stunt, one the American builders Swiss type automatic successfully turned pin 0.005 in. diameter and in. long. regular produc- tion instrument plants, pivot points 0.013 0.018 in. diam- — ABOVE 2—A few the many types small instrument parts which have been produced Swiss type automa- tics one opera- tion. LEFT 1G. ar- rangement the tools Swiss type automatic. The two lowest tools are mounted single rocker arm pivoted about stud direct- below the support bushing through which the work pushed. The rocker arm cam may seen the left. (Gorton machine.) eter are being turned size within 0.0003 in. size. Jobs that are turned out ex- tremely rapidly are accomplished feeding out and cutting off three four pieces with one collet grip- ping, thus reducing the non-produc- tive time. Where number different di- ameters are turned and par- ticularly where step-back diameters are necessary, the only possible way handle such cuts turret type machine (in which the stock first broad faced form tool, either cir- cular dovetail. Such tools, how- ever, impose heavy cutting forces the stock, since the “depth” cut equal the width such tools. This rules out their applica- — = 28—THE IRON AGE, January 28, 1943 thin ex- shed di- par- eters way type first cir- how- forces such tion long, slender parts where the deflection the work under load would make impossible meet the tolerances for. somewhat heavier work, the other hand, conventional auto- matic possible use one the turret stations for back rest support for the end long pieces. With the Swiss type automatic, even the most intricate forms and smallest diameters, pos- sible hold critical dimensions within 0.0002 in. specified size. This attributable the rigid support given the work right next where the cutting tool load applied. Single point turning tools are work and the feeds are light compared with cuts taken with bar turners, for example, conven- tional screw machines. Tapers Curves Generated Due the radial feed the tools readily possible turn piece with raised shoulder the middle simply dropping the tool back the lower diameter after the stock has been fed past the shoulder portion. suitable govern the radial infeed with rela- tion the stock feed that taper any angle even curve, like portion sphere, can gener- ated single point tool. This compares with cutting tapers with swing tool the turret conventional single spindle auto- matic. proper camming the head- stock feed, also possible re- tract the headstock any point without releasing the collect chuck back recess, such as: illustrated Fig. Drilling and tapping thread- ing operations can performed the end the piece, through the medium end working attach- There are these differences noted from conventional ma- chines: the first place, the device limited drilling two diameters drilling one hole and then tapping it. possible thread one diameter with the end attach- ment and thread second diam- eter with thread roll tool one the radial tool holders. During and thresding operations, the headstock feed usually remains Provision can made for step drilling deep holes, simply arranging pull-outs the cam which controls infeed the end IG. 3—A difficult 60° job like this, with many different di- between them typical the type work that can handled one op- eration Swiss type machine. (Wickman sample.) 0198- 026)» ¥ ~ Stainless steel Spindle speed- rpm. piece 4—Example back re- cessing small part. This accomplished back track- ing the headstock and stock feed for necessary. tools. Usually solid, acorn type adjustable chaser dies are used that the relative motion the die must reversed, although self- opening dies have been applied. Tap Reversal The headstock spindle has only one direction rotation, and and unscrewing the Swiss type machines done the differential system over and under-speeding the following manner: Suppose the main drive 3-56 Tap spindle machine rotates 7000 r.pm. thread on, the die spindle rotated 9000 r.pm., the same direction, giving relative thread- ing speed 2000 r.pm. second pulley the attachment rotates 5000 r.pm. double taper friction clutch allows one pulley de- clutched and the other engaged in- stantly. the example cited, the solid acorn die backs out 2000 r.pm. due overrunning the work. alternative method real small work apply brake 5—The Wickman machine departs farthest from the original Swiss designs view its British-Swiss parentage. at a s¥ H ‘ r | THE IRON AGE, January 28, 1943—29 the tapping spindle, which case the backing out speed even faster. When self-opening die heads are used, only one speed (fast) need used for threading on. Lead screws are not employed for the threading attachment. The cam starts the die tap the stock for few turns and then allows the threading tool follow its own lead. Usually these end working at- tachments have two the three spindles geared together, and the three are successively rocked into position. The first spindle usually cams for the Wickman automatic. These are typical other designs far the cams are concerned. carries stationary spotting tool start-drill. The second spindle for drilling and the third for threading, either external inter- nal. Deep holes can drilled with three four pullouts clear chips from the hole. Small drills are driven high speed order get the proper peripheral speed for efficient cut- ting. This accomplished driv- ing the attachment spindle reverse direction from the work spindle that relative one an- other the two speeds are added. This readily obtained gearing 7—Rear view the latest type Ceco machine, showing the large headstock plate cam overhanging the end the bed and the separate motor drive for the cam shaft. > 1 q < & 30—THE IRON AGE, January 28, 1943 the drilling and tapping spindles to- gether. Feeds Are Light Feeds these Swiss type auto- matics are generally light, com- pared with the feed for box tools the turret conventional au- tomatic. They are more nearly comparable with the feed cir- cular form tool which must neces- sarily low because for straight infeed the depth cut equals the width the tool. When turning stainless steel, for example, feeds for forming cuts range between 0.0003 and 0.0005 in. per rev. and straight turning operations 0.0002 0.0007 in. per rev. Cold drawn steel and non-ferrous stock can turned much greater feeds, depending upon the finish and accuracy desired. fact, any machining operation, choice feed largely governed the finish required. diameters that are later ground, the turned finish immaterial and high feeds can used. When form tools are used the cross slides conventional auto- matic, stops are used limit the amount infeed and hence con- trol the diameter the work irre- spective any slight errors cam profile. Except the rocker tools, not possible provide such depth control the Swiss type ma- chines. Instead, diameter control definitely function cam accu- racy. Generally, however, each ra- dial tool turns only one diameter and partial compensation, each radial tool slide provided with micrometer adjustment correct slight errors base diameter. will seen Jater article, equipment developed abroad for the accurate milling cams and American copies are now the market. also has been devised for checking cam contours special microm- eter. addition, the leverage ratio between tool feed and cam rise and fall 3:1 2:1 many the radial tools, that radial errors cam profile are halved the tool. some machines, these ratios can varied, allowing modification the cam rises. The answer in- herent accuracy, however, that experience shows that even very small diameters (0.012 in.) the di- mension can held within two three “tenths.” Size accuracy and fine finish are favored the use light cuts and slow feeds. es ratio and the tool. can in- that very di- and ise 8—How the rocker tools are oper- ated single cam. When the front tool rocked into position, the rear tool withdrawn. See also Fig. The original Swiss machines that were imported into this country, prior the war, were all very much alike mechanical details. the first place, the three principal Petermann, the Bech- ler and the Tornos—were all manu- factured the same town Mou- tier, Switzerland, and many the workers have been employed all three companies one time an- other. Changes American Models addition American version the Wickman Swiss type auto- matic being made this coun- try, Fig. departs farthest from the original Swiss design view its more immediate tor, British model (A. Wick- man, Ltd.). Now that these machines are be- ing made this country, many de- sign details have been incorporated line with best American machine tool practice. They all necessarily conform the basic principle stock feed through bushing and tool feed fixed plane that distinguishes this type auto- matic. The chief changes have been made the drive means, use heavier construction, cleaner lines and refinements attachments, such the end feeding attach- ment and the slotting attach- ment. Some are using separate motor for the cam shaft drive (the Swiss machines have single motor drive) and several the American models incorporate variable speed drives. Anti-friction bearings have been added some places. Some the drives for the slotting de- vices were particularly awkward some the Swiss machines. The fact that Swiss machines were originally imported has com- plicated the marketing set-up fur- ther that selling agents were al- ready set this country and some still remain the picture for marketing the American made models. The table page shows the genealogy these machines and their American parents. 9—In the medium position, both rocker tools, shown Fig. are clear the work. Swiss type automatics have only single cam shaft, which carries, however, more cams than are found conventional single spindle automatic. There one cam for tools Nos. and which are mount- common rocker arm, and each the other tool slides (two three) has its own cam. Head- stock movement controlled cam either the disk bell type, Fig. bell cam also used for feeding the end tools the ment, and flat cam employed for indexing these tools. There also trip dog for belt shifting clutch control for threading opera- tions. (Over and under-speeding get tap die reversal.) the original Swiss machines, flat headstock cam was employed where the work length ordinarily did not exceed 234 in. For lengths in. bell cam was invaria- adjustments are provided for endwise (radial) and sidewise (axial) location each ‘tool. These photographs show front and rear views the Wickman head. THE IRON AGE, January 28, ols rly ir- es- the ing ons ock the hat ned eds the uto- the rre- cam such ma- each with rrect speed drives for headstock and crankshaft are provided the Gorton-Petermann machine. Speed controls are centralized the panel the right. bly employed. This practice gen- erally followed the American models. longer lengths are produced possible release the collet, retract the headstock and feed forward again, thus practical- doubling the work length capac- ity. The end feeding attachment must used temporary stock stop while the collet getting “fresh grip” the work. also possible accomplish the same re- sult with shoulder cutting tool acting stock stop. the latest model Ceco ma- chine, flat plate cams are used for headstock traverse either long short work. letting this cam overhang the end the bed, Fig. for long traverses. Primarily this change was made not elimi- nate bell cams, which present difficulty from the production an- gle, but simplify the layout the headstock cam, particularly for straight taper turning. the orig- inal Swiss machines, rocker arms and bell cranks are used trans- late the cam follower motion right angles for headstock feed. Arc templates corresponding rocker radii must used for lay- ing out cams ordinarily. the Ceco unit, the effect rocker arms has been eliminated straight line translation move- ment from plate cam. Straight radial cam layout can used: letting this cam overhang the end the machine, can made large need and re- places bell cam for long traverses. The cam follower moved vertical- American Manufacturers Original Swiss Automatics Original Swiss Types American Agent American Maker Bechler Triplex Machine Tool Corp., New York Petermann Russell, Holbrook Henderson, Inc., New York Tornos Wickman* Wickman Corp., Detroit **City Engineering Co., Dayton, Ohio ***Geo. Gorton Machine Co., Racine, Wis. Thomas Gibbs Co. Sheffield Corp., Dayton, Ohio origin (A. Wickman, Ltd., England) Bears the Ceco name *** Bears the Gorton name 32—THE IRON AGE, January 28, 1943 straight guides and bears roller the end rocker arm. The other end the arm bears turn against pivoted flat shoe, carried the end bell crank. The other arm the bell crank transmits its motion vertical slide bar the headstock through roller. This arrangement gives straight line translation move- ment throughout. Rocker Tools Camming the cutting tools identical all models, but feed for tools Nos. and different from other tools the head. will noted from Fig. that these tools are mounted common rocking arm, the hardened pivot point which directly below the work bushing axis. When tool No. rocked into cutting position, tool No. backed away. Fig. shows the medium position with both tools clear the work 0.020 in. single cam controls the movement the rocker arm and coil spring holds the follower toe engage- ment with the cam. Gorton plans multiple camming device for the rocker tools that the ratio rocker cams can varied. Roller followers are not used plate cams. Necessarily, movements tool No. (front rocker tool) are governed the variations the minimum radii the cam, and those tool No. (rear rocker tool) variations the maximum radius. These rocker tools are gen- erally selected carry the heavier cutting loads and for multiple diam- eter camming. Each tool mounted auxil- iary rocker for adjusting the tool center. addition, screws with micrometer dials are provided for adjusting the tool carriers radially and the axial direction. fact, Fig. shows, each tool holder has micrometer adjustments this nature. has been mentioned, radial control compensate for slight errors base circle diam- eters cams. Radial Tools Each the upper radial cutting tools (Nos. and are pro- vided With individual cams, which are the C-type that they can slipped over the camshaft be- tween its support bearings and locked between collars tightened | j ting pro- hich can be- and spanner wrench. The cam follow- ers toes are pivot shaped and bear directly the cam. Most fol- lowers are made tool steel and are V-shaped. the Wickman ma- chine, they are tipped with hard grade carbide. Cams for the rocker operated tools are the solid type, the other hand, since these tools carry the major portion the cutting load. One two cams may used. There are several variations the method transmitting the mo- tions the cam followers the radial slides. general, the mech- anism involves rocker arm top, pivoted link carrying the cam fol- lower and connecting rod. Shift- ing the upper end the rod slot the rocker arm aliows the ra- tio tool travel cam travel varied from 1:1 3:1, depend- ing upon the type machine. this way standard cam motions can modified suit variety jobs within limited range. Since the followers are pivoted arms, laying out the cams, tem- plates corresponding the radius the arms must used pro- jecting the degree divisions the periphery the cam layout disk, line with standard practice conventional machines. should noted, however, that the cam Plate divided into 360 divisions instead 100. this connection, should emphasized that cams must laid out very accurately since the rise the cam definitely determines work diameter. conventional automatic, where box tools are used the turret, the diameter gov- erned the tool setting. Swiss type automatic, even when generated perfectly and Collet chuck checks against micrometer set-up, there may variations diameter work. Some cams have taken back the miller and smoothed with burnishing tool. This one reason why the use standard cams desirable, once good form developed. also highly important that cylindrical portions radial feed cams con- centric with the camshaft, other- wise taper will develop the work. one aircraft instrument plant, use standard cams makes pos- sible use Swiss automatics for many 1000 pieces, bettering the unit cost obtained hand screw machines, including set-up time, etc. placed with either roller chain V-belt. the Gorton version, Fig. 11, for example, separate 1/3-hp. motor V-belted Graham va- riable speed reducer and the output shaft connected the worm- wheel shaft roller chain. knurled disk used for obtaining speed variations and this protrudes through the control panel. dial gage hooked mechanically with the control disk and reads either r.p.m. pieces per min. the prototype Petermann ma- chines, single flange-mounted mo- tor drives both headstock spindle and the camshaft. Separate camshaft drive from variable speed unit also used the Ceco machines. the rear IG. 12—The headstock spindle construction the original Petermann machine. This design closely adhered the American made machines, with the exception the Wickman automatic. the Rolex mechanism (head- stock feed lever system) the Bechler machines used here, possible vary the ratio head- stock travel cam rise from 1:1 all the way 10:1, thereby tak- ing care wide variety lengths work with single cam. Neces- sarily, there some loss produc- tion time involved. Whereas with modified standard cam, 320 pieces might produced hour, with specially cut for the purpose, 370 pieces, per cent more might produced. Set-up time with standard cams hr. special jobs, set-up time around hr., not including the time cut new cams, which takes about hr. after they leave the “board.” Camshaft Drives American builders have all im- proved upon the drive the cam- shaft. While retaining the final worm and wheel drive, the original right angled “mule” drive arrange- ment with round belt has been re- view this machine shows, Fig. the motor and Master “Speed Ranger” variable speed change unit are mounted above and right angles the main drive motor, per- mitting simple two-stage V-belt drive the camshaft worm. the Wickman machine, the other hand, camshaft speed changes are made through change gears and power transmitted from con- stant speed shaft driven off the main spindle motor. gear box interposed, however, and provides gearing and clutches for accelerat- ing the camshaft during idle move- ments the tools. The accelerating mechanism by-passes the change gears and speeds camshaft sec. cycle rev. sec.) during the non-cutting periods. This advantage long cycle jobs, where ordinarily deg. 360-deg. cam circle taken with retraction tools, opening collet, advance stock, closing collet and with- drawal cut-off tool start cutting operation before stock feed THE IRON AGE, January 28, | ‘or ols and ker vier am- tool vith for ally act, this ned, for am- q takes place. also important where long section work left unturned ground rod stock. this case the headstock can advance the stock rapidly during the non- cutting period. Roller chain used between the gear box and the this installation, also. Both Ceco and Gorton use varia- ble speed drives the headstock spindle, the former through Mas- ter unit and the latter through Reeves drive. Both units drive wide drum over which flat driving belt travels during the feed the headstock. the Wickman machine, spindle speed changes are accomplished changing the outside pulleys the main drive shaft and the motor pulley, speeds being obtainable this manner. ingenious arrange- ment bearing retainer has been provided for using endless belt the inside drive drum without removing the shaft. The driven pul- ley the headstock ball bearing mounted independently the spin- dle proper, which driven through splines. The front end the spin- dle carried tapered bronze bearing which lapped close limits, while the rear carried preloaded ball bearings take the thrust well radial loads. Collet Operation Stationary spring type collets op- are generally employed machines. Fig. shows cross- section Petermann spindle, which also typical present American designs. fork controlled self-locking mechanism operated trip dogs carried drum the cam shaft. These dogs may adjusted around the periphery the drum and are similar action conventional clutch trip dogs. the usual set- the cut-off tool completes its opera- tion, the collet opened, permit- ting the stock remain against the cut-off tool the headstock withdrawn the starting position. The collet then tripped and the machine ready for another cycle. Stock Feed most designs, both foreign and domestic, stock fed through slotted tube gravity pusher finger. weighted load applied against the finger through ar- rangement flexible wire and pul- leys. the pusher nears the head- 34—THE IRON AGE, January 28, 1943 split type guide bushing (Wickman). mounted the tool head the spindle center split tapered bear- ing. close running fit between stock and tool steel split collet obtained through the adjusting screw the right. Bushings can had with serts for long wear life adjustment. ° ° stock, contacts trip switch which stops the machine. the Ceco there double micro switch stock control. When the first switch contacted the pusher bar, energizes second switch which then tripped dog the collet control disk the completion cycle the piece. This prevents stopping the machine the middle cycle. the Gorton version the Petermann machine, Lipe-Rollway air feed used place grav- ity stock feed. tell-tale light used conjunction with micro switch warn stock exhaustion. that the stock pusher becomes effec- tive only when the collet opened the completion cycle and then largely performs the func- tion holding the stock against - 14—Revolving type guide bushing. The Wickman design typical all Swiss type automatics. Wickman also supplied self-adjusting style with coil spring tension. the cut-off tool (which serves stop most set-ups), while the headstock withdrawn starting position. Feed force for the head- stock applied through the head- stock cam, and aided the feed weight. Materials small diameter pieces these machines, material specification has definite bearing the quality finish and the ac- curacy obtained. That why car- bon drill rod (0.95-1.05 fre- quently used for this purpose. Drill rod, this instance, bought greater lengths than the standard 3-ft. sections, but the same ances in. for sizes from 0.125 0.500 in. and +0.0003 for under 0.125 in. are called for. They are centerless ground perfect roundness and polished finish. These materials should free from surface decarburization and any flaws inclusions. For this reason, rigid mill control heats speci- fied. This costly material. the smaller sizes (0.013 0.016) the price runs around $35 pound, without extras for length special finish. “Pinion stock” commonly used for clock, meter and instrument parts. This material similar bessemer screw stock, but toler- ances and finish are identical with drill rod. the war effort, great deal stainless steel rod being turned these Swiss type auto- matics. presents special prob- lems, except that the feeds are nec- essarily lower. number non- ferrous materials are also being machined, particularly aluminum and brass. Fit Bushing The close diameter control stock has direct bearing the accuracy work performed that governs the fit play the stock the guide bushing just back the working plane the tools. Although there may size varia- tions in. any bundle drill rods, any one rod will have the same Hence real fine work the bushing will adjusted separately for each rod give push fit. The bushing usually split three sectors and mounted collet type hold- er, Fig. 13. While the standard bushing made hardened tool steel, some American builders are supplying bushings with hard car- bide inserts for long wear. One a. Bushing. pins 7 the that the back tools. have hout. shing shing and hold- ndard tool are car- One maker using Ampco bronze. Be- cause their anti-weld properties, these inserts are particularly rec- ommended when turning stainless steel other “gummy” material that tends smear the bushing and result sometimes complete seizure. alternate type bushing for use with stainless steel for stock that out round hexagon other than round shape, the revolving bushing, Fig. 14. collet type bushing employed here also. Wickman provides both manually adjusted and self-adjusting type, the former corresponding orig- inal Swiss designs. either type, ball thrust bearing needed, and positive rotation the whole bush- ing provided special driving plate mounted the headstock spindle nose, drive being through two hardened and ground pins. against the stock the self-adjust- ing type maintained helical spring pressure. This should enough prevent rotation but per- mit sliding. This sort arrange- ment compensates for slight varia- tions diameter cold rolled stock and obviates the need for specifying centerless ground stock. Finely Ground Tools Where fine finish and close diam- eter control desired, neces- sary use not only fine feeds, but also finely ground tools. For the average run jobs, square stock high speed steel (5/16 in. max.) ground all four sides aids the precise setting the tool bits the holders. addition, the faces and clearance angles ground leave clean, sharp edges. Usually the tools cut cen- ter and rake employed. Cor- ners are necessarily sharp for close shoulder work, and radii, any, are the nature 0.010 0.015 in. turning stainless steel, the wear these corners severe and this means the tools have pulled out and reground about every hour two. Hence cemented car- bide tools are being widely substi- tuted for H.S.S. obtain longer runs between grinds. These tools are invariably diamond lapped mirror finish. One aircraft instrument plant uses carbide tools almost exclusive- and runs the machines faster. better finish obtained the work and longer tool life results. The tools are all carefully prepared diamond lapping. later article, tool layouts and camming some typical instru- ment jobs will discussed. Rapid Heating for Propeller Forming EATING shank for important forming operations done ap- proximately one-fifth the time for- merly required, the elec- trical induction process developed the Ohio Crankshaft Co., Cleve- land. The shank the hollow steel propeller blade first heated pre- paratory swaging, operation which the shank rounded perfect circumference. The blade mounted movable rack the front the 100-kw. Tocco machine, shown the photograph. The tubular shank section, in. diameter, the base the blade then moved forward until surrounded the heat inductor coils the unit. When the operator presses the button, electrical current high frequency flows through the inductor coils, and about in. the steel propeller shank heated approximately 1700 deg. 150 sec. When the cor- rect temperature reached, the operator hooks the blade overhead spring balance crane and ton forging machine. the completion the swaging the blade passes through two welding processes, thorough inspection and lathe machin- ing operation before again mounted the movable rack and heated second time the electri- cal induction unit for 210 sec. temperature about 2200 deg. When the proper heating at- tained, the overhead crane again conveys the heated piece the ad- jacent upsetting equipment few seconds. The upsetting operation consists forming the heated shank three-pass set dies increase the wall thickness the shank from 0.520 in. approximately 13/16 in. and decrease the length the shank area from in. in. Propeller blade shank being heated 2200 deg. 210 sec., prior upsetting. THE IRON AGE, January 28, ar- } ‘ re- er- for 1ey ect ish. ‘om any the the ind, cial ised vith reat uto- rob- nec- non- eing num | Steel Carburization and reaction between me- thane* and iron The equilibrium constant for the above reaction written: H,) (Nre) (14) assumed here that higher hydro- carbons decompose according the fol- lowing reaction: (13) The methane-iron equilibrium has not received much atten- tion the moncxide equilibrium. The work perhaps outstanding. The null method studying the equilib- rium between hydrogen methane mixtures and iron not very sensitive one. annealed sheets various carbon contents given temperatures mined which mixtures methane- hydrogen were neutral the steel. The constant for this reaction has been calculated from the data Schenck and given Table III; plotted Fig. The mathematical expression for the change with temperature written as: TABLE Equilibrium Constant Equation H,) Nre Temp., 1/T 925 8.3 +0.185 Calculated from equation 36—THE IRON AGE, January 28, 1943 JAMES STANLEY Westinghouse Electric Mfg. East Pittsburgh While Fig. important for expressing the variation the equilibrium constant, its useful- ness not obvious without some study. more useful plot shown Fig. where the me- thane plotted against carbon. the temperature increased, the carbon content steel equilibrium with given methane content increased. Or, other words, the mixture becomes more with increasing tem- perature more methane be- ing decomposed give carbon the metal. This true because methane more stable lower temperatures. The effect pressure the methane-iron equilibrium dif- ferent from that the carbon- monoxide-iron equilibrium. the present case, one mol methane decomposes into two mols hy- drogen, while the former (mon- oxide) case, the two mols mon- oxide decompose one mol Temperature deg.C. 1G. 5—Variation equilibrium con- stant CH,-Fe re- action where 4.57 Equilibrium constant (in temperature deg.K 0.9 ~ | ° ° ° 0 the rbon- the thane mon- pressure, course, affects the equilibrium constant. algebraic manipulation can obtain 16) Carburization Differences with and CH, While carburization can accom- plished the reactions discussed —the monoxide and the methane— there exist distinct differences. The first difference the relative stabilities the carburiz- ing constituents. Suppose one con- siders the pure substances. Car- bon monoxide increasingly stable elevated temperatures, that less carbon available for carburization the temperature increases. This means that cer- tain concentration CO, say per cent, equilibrium with steel less carbon content the temperature increased. This seen below: TABLE Carburization CO-CO, deg. Percent Steel 1740 1.30 1830 0.80 1920 0.55 2012 0.32 The data are taken from Fig. Methane, the other hand, increasingly unstable elevated temperatures, that the tem- perature increased, more carbon available for carburization. This means that certain concentra- tion CH,, say per cent, equilibrium with steel greater carbon content the temperature increased. This seen below: TABLE Carburization deg Percent Steel 1740 0.36 0.57 1920 0.73 2012 1.05 The data are calculated from the equilibrium constant. The second distinct difference Theoretical Analysis Continuing last week's discussion the thermody- namics gas-metal reactions, the behavior the varia- bles, temperature, pressure and concentration the methane-hydrogen mixture, towards iron outlined. The theoretical aspects steel decarburization are also presented. between the two compounds that with the carbon oxides, oxygen introduced into the steel, but with methane this not the case. ized with mixtures carbon monoxide and carbon dioxide, certain amount oxygen in- troduced simultaneously with the but the amount oxygen absorbed usually very small, less than 0.01 per cent be- tween 1470 and 1830 deg. states that oxygen in- troduced pack carburizing. This oxygen penetration would depend upon the steel. killed steels, the oxygen diffuses with the carbon, but slower rate. rimming steels low manganese (already saturated with oxygen) oxygen would penetrate diffusion. Un- doubtedly highly oxidized steels would possibly lose oxygen during carburization, for the oxidizing constituent the carburization process reduced, less oxygen the metal equilibrium with it. duces oxygen, and perhaps even removes it, especially with hydro- gen present. carburized steels the relation between oxygen inclusions and the dependence grain comes apparent from the distinctly different grain pattern the case, compared the unchanged core. Oxygen adsorption exceed- ingly marked steels having some dissolved aluminum. Oxygen elevates the coarsening tempera- ture the steel, that sharp change grain size manifest the limit oxygen penetration. Hydrogen-Cyanide Reaction Equation (10) was mentioned once connection with equilib- rium reactions: far the author knows, there has not been study this re- action. Commercially method has been perfected which termed dry- this case ammonia added natural gas intro- duce carbon and nitrogen. The advantage such method that one can case-harden tempera- tures low 1150 deg. be- cause the nitrogen decreases the critical points steel. Quenching often unnecessary, the mate- rial sufficiently hard due the nitrogen. Liquid depends upon the oxidation sodium anide the cyanate according the equation: 2NaCN 2NaCNO (17) The cyanate then decomposes shown (18) The carbon monoxide dissolves the bath and upon contact with iron assumed dissociate carbon and carbon dioxide; the THE IRON AGE, January 28, | | | - ° | | | — = q 4 | | | f | atomic nitrogen absorbed such. The chemistry activated baths containing CaCN, and probably different. There appears little cer- tainty the actual carburizing mechanism liquid baths. Fur- thermore, extensive study equilibrium reactions between the fused salts and steels appears available. Decarburization Steel the undesirable consequence improperly controlled heat treat- ment. Decarburization usually re- sults decrease hardness, but decarburization austenite steels may bring about martensitic hard- ening. some cases, however, the purification metals decarbu- rization may sought. Decarbu- rization can take place two ways: (a) change the equilibrium between the carburizing gases and the iron, may take place such way that the atmosphere will de- carburize given steel. has been mentioned before, the carbon monoxide and methane reaction (2) and (7) may de- carburizing well carburiz- ing, depending upon the concen- trations, temperature sure. this case, the equilibrium constant (K’) the reciprocal the constant for the carburizing reactions mentioned before. The constants are now written (Nre) (9) (b) Oxidation occurs with atmosphere, which oxidizing both constituents but different degrees. The decarburization effected oxidation the gaseous phase such substances oxygen, moisture and carbon dioxide, and the liquid phases, any oxidiz- ing fused salt. Oxygen very powerful de- carburizer iron) + CO, Fe (19) but accompanied film forma- tion scaling. Another very important decar- burization reaction that the carburized iron with moisture. iron) + H.O CO + H, + Fe (20) 38—THE IRON AGE, January 28, 1943 | al 6—As the temperature in- creased, the carbon content steel equilibrium with given methane con- tent increased. Methane, per cent Carbon dioxide itself strong oxidizing agent, reacting with steel follows: Ccn iron) + CO, =— 2CO + Fe (2) might supposed that nitro- gen itself might decarbur- izing agent, behaving according the reaction iron) N2 z 2CN + Fe (21) There evidence that the molecular nitrogen such can form cyanogen. might pos- sible decarburize iron with atomic nascent nitrogen. Data this are lacking, and the vol- uminous writings the subject indicate that where nitrogen was found decarburizing, was due impurities such oxygen, moisture carbon dioxide. Decarburization with Carbon Di- oxide: The reaction carbon di- oxide with carburized iron (Equa- tion has been discussed, but this case considerable excess exists drive the reaction the right. elevated temperatures such those which carburizing carried out, say 1740 deg. F., 0.02 0.03 0.04 Ratio 042 063 0.84 1.05 Carbon, per cent haps per cent, will reach equilibrium with any steel less than 0.1 per cent carbon. per cent tool steel had been terrific loss carbon. These re- lations are obvious from Fig. The presence carbon dioxide often responsible for decarbu- rization. Even the carbon di- oxide removed before the gas enters the furnace, the carbon monoxide may react the hot zone form carbon dioxide. prevent such reactions, the carbon dioxide and moisture must both removed. should borne mind also that high concentrations are oxidizing iron well carbon: FeO Temperature effect decarburization, usually increasing unless there the entrance complicating factors. With decarburization 1650 and 2012 deg. rapid, but (23) | 9 | | 0.05 per- less been re- 9 gas arbon hot (22) the must also CO, 9 (23) isually the actors. 1650 but 1470 deg. the formation oxide scale interferes with decarburi- zation. Decarburization Hydrogen: The question decarburization hydrogen has often been ar- gued. Some say that pure, dry hydrogen decarburizing, while others have The question undoubtedly has been complicated the presence moisture. Pure hydrogen with decarburizer, but very slow one. The reaction for the austenitic range could written: and below the eutectoid tempera- ture: Pure, dry hydrogen sidered decarburizing the other hand, moist hydrogen hydrogen satu- rated with moisture room tem- perature, about per cent (vol.) for very good this case the reaction different, and can written: The effect moisture hydro- gen seen Fig. Irregulari- ties the curve can explained the basis ferrite formation due slow ature, which means that more bon monoxide formed with in- creasing temperature. Hence, rise temperature hastens the rate surface reaction. Decarburization with Oxygen Air: Oxygen decarburization oc- curs according equation (19), well