The Iron Age 1940-08-15: Vol 146 Iss 7

WRIGHT Managing Editor OLIVER AUGUST 15,1940 VOL. 146 VAN DEVENTER President and Editor BAUR Vice-President and General Manager ROWAN News Editor T. W. LIPPERT Technical Editor Associate Editors Art Editor Editor Emeritus Washington Editors MOFFETT JAMES ELLIS Resident District Editors CAMPBELL ROBERT BINGHAM Pittsburgh Chicago Cleveland Detroit Editorial Correspondents Buffalo Cincinnati FRAZAR CHARLES POST Boston San Francisco HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis LEROY ALLISON Newark, Editorial Technical Articles Fatigue Cracks Products Advertised Index Advertisers Improvident Pop The All-Basic Open Hearth Tooth Bearings Bevel Gears Accuracy Aircraft Fuel Pumps How Rate Employees Plastics-on-Metal Finishes Feature Reports the Assembly Line Washington News News and Market Reports Personals Obituaries Metal Working Activity...... Comparison Prices Summary the Week. The Industrial District Market Reports 100 Advertising Staff Emerson Findley Union Bid Robert Blair Union Bldg., Cleveland Hermon, Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago Leonard, East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York Warren, Box Hartford, Conn. Don Harner, 1595 Pacific Avenue Long Beach, Cal. Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub- Price: United States and Possessions, Mexico, Cuba, $6.00: Canada, $8.50; Foreign, 312.00 year. lished every Thursday. Subscription Single copy, cents. Cable Address, Y." Machine Tool Activity Non-Ferrous Metal Market Scrap Market and Prices. Construction Steel Iron and Steel Ferroalloys, Pig Iron Price Warehouse Sales Possibilities 108 Owned and Published CHILTON COMPANY (Incorporated) Publication Office Chestnut and 5éth Sts., Philadelphia, Pa. U.S.A. OFFICERS AND Editorial and Executive Offices 100 East 42nd St., New York, Y., U.S.A. DIRECTORS MUSSELMAN, President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, BAUR, JOHN BLAIR MOF Vice-President Vice-President Vice-President Vice-President Vice-President WILLIAM BARBER, Treasurer FETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALE 106 32—THE IRON AGE, August 1940 Immediate Shipment Assured The ability deliver promptly course, outstanding impor- tance today, but Ryerson offers still more. The buyer who may need angles. sheets. bars, welding rod, and many other items assured uniform high quality regardless the size his order. Under the Ryerson Certified Steel Plan. stocks include only selected products that meet the most demanding specifications. The purchaser can then concentrate orders for practically all his steel securing uniform high quality and quick service saving time and money. Ryerson certified alloy steels are outstanding example the care used the selection our stocks. assure entire heats (100 150 tons) alloy that meets our narrow range specifications are secured. Bars are analyzed and tested for chemical and physical properties and heat treatment response. Every bar clearly identified with the heat number. Data sheets and charts showing properties the steel and results the tests are prepared and sent with every order, large small, guide heat treatment. This valuable service given extra cost. Ten large Ryerson plants carrying more than 10,000 kinds, shapes, and sizes steel products stand ready meet both your regular and emergency requirements. you not have the current Ryerson Stock List, shall glad send copy. Joseph Ryerson Son, Inc. Chicago, Milwaukee, St. Louis, Cincinnati, Detroit, Cleveland, Buffalo, Boston, Philadelphia, Jersey City. q F 4 } ‘ YP bir mm Y U AUGUST 15, 1940 ESTABLISHED 1855 Improvident Pop little story about benevolent papa which may have point application present-day affairs. “Pop” was free spender and good his family. bear refuse anything that they asked for. Willie and Jack had have their own cars, course, because college life without automobile was not thought of. And the Mrs. and Mabel had have fur coats that would match those the neighbors. All this kept Pop pretty close the cushion, for business been good used be, but managed keep pace with the help mortgage and bank loan. That is, managed keep until Willie took sick. Willie, the eldest son and junior college, came down with mysterious disease that the doctors seem diagnose. Specialists and nurses were called and the bills followed after them until Pop’s checking account and his savings account were completely blitzkrieged. And the worst part was that the doctors said would take several years medical and nursing care bring Willie out it. Pop went down the bank, but the banker said no. And not having printing press with which print dollar bills, Pop took the only course that sane and sensible man could take under the circumstances. called family council consider economies. None the members the family liked the idea giving anything that they had, including their standard living. But neither did they like the idea losing Willie because lack means sup- ply what needed. like good members good family should, they agreed economize that Pop could put his income where was urgently needed was hard first without new fur coats and cars and cook and maid, but that was forgotten after while the happiness seeing Willie get better and knowing that the bills were being paid and the family kept out the poor house. You, gentle reader, may say Wouldn't any self-respect- ing family head insist economizing under similar And will answer this asking another question. “When the Great White Father Washington going take similar action pro- vide the means for pulling his family Americans through this epidemic Ten billions year additional for specialists and nurses put fighting top $45 billion debt would seem dictate little economy. Strange, isn't it, it, that one kind dictated economy wel- comed Washington and the other kind given the cold shoulder? | ) | | | 4 ve { | \ : The cab body this shovel enclosed with Inland Hot Rolled Sheets. THERE Selecting long has been since you have looked for profits hidden buying habits that not keep pace with engineering design and: consumer reference? Many leading manufacturers, now cus- tomers Inland, are keeping buying habits abreast every move made their engineers—and they find profitable. case point the shovel cab, shown above. This cab now enclosed with Inland Hot Rolled Sheets. These sheets, rolled Inland continuous mills, are true gauge, have excellent forming PROFIT the Steel qualities and smooth, flat surface. They meet every requirement workability and finish. This change Inland Hot Rolled Sheets good ex- ample co-ordinating engineering design, con- sumer preference and buying practice. The most effective way check buying habits call Inland engineer. finds ways im- prove your finished products, reduce the cost manufacture, you gain his efforts. His serv- ices are yours without obligation. SHEETS STRIP TIN PLATE BARS PLATES FLOOR PLATES STRUCTURALS PILING RAILS TRACK ACCESSORIES REINFORCING BARS > Dearborn Street, Chicago Milwaukee, Detroit, St. NTEREST very keen the possibilities all-basic open hearths for steel manu- facture the United States. Thus, this article most timely. Herein, the first section this two-part ar- ticle, the author covers the development chrome- magnesite brick, describes its use furnace roofs, and gives detailed data tests basic brick for furnace construction. use silica brick for the construction hearth furnaces above) the melting point silica, and containing atmosphere loaded with iron oxide and lime (see Table probably the greatest compromise the field steel works refractories. The fact that silica brick has been able maintain this position due the main three outstanding (1) High refractoriness under load. in. within few degrees its melting High thermal shock resistance above critical temperature, viz., about 1112 deg. without any serious drop melting point. spite these advantages, the life silica brick open hearth furnaces very limited. gas ends and air ends may only amount about three weeks, while with fast working furnaces, the life the roof often not more than months. Any at- tempt raise output driving the furnace harder tends result serious drop furnace life. Faced with this obstacle increased produc- numerous attempts have been made develop brick which, addition being far more refractory, show adequate resistance basic dusts. Given such refractory, out- put could considerably increased without the necessity building new furnaces. That such object not just idle dream has been amply demon- strated the results obtained with all-basic furnaces during the last few years. Dozens such furnaces have been built and many them have jus- tified the highest hopes those who installed them. Certain plants, among them those which did much the pioneer work, have been disappointed, but this inevitable field which progress often only comes the result sad experience. The greatest obstacle progress has been the physical limitations basic refractories. The ordinary mag- nesite brick very heavy and there- fore requires much stronger roof suspension. spalls rather readily and has comparatively low refrac- toriness under load. addition, its conductivity high. special chrome-magnesite brick that has made the all-basic furnace practical prop- osition (at least for certain purposes still very heavy but has refrac- toriness under load approaching that silica brick, and addition high thermal shock resistance. has long been known that the addition small amount mag- nesia improves the properties chrome-magnesite brick CHESTERS Central Research Department, United Steel Companies, Ltd., Sheffield, England tally reduces the difficulties manu- facture, particular the risk squat- ting during firing. The special chrome- magnesite brick today is, however, the result great deal systematic research mainly carried out this country, the United States, Canada and Austria. The results this re- search (much which has been cov- ered patents methods making fired and chrome-magnesite brick) can summarized the de- velopment basic brick three very important properties, (1) High thermal shock resistance. (2) High refractoriness under load. (3) Volume stability high tem- peratures. Without these properties, which can only obtained the careful selec- tion raw materials, accurate grad- ing, and high molding pressures, the chrome-magnesite brick cannot hope compete with the silica mag- nesite brick, even back and front walls. The high thermal shock resis- tance special chrome-magnesite brick depends careful control the grading. With fired brick generally obtained keeping the chrome fraction (generally per cent the total) the coarse section and the magnesite (40 per cent the total) the fine sec- tion. The high refractoriness under load depends the conversion the low melting point gangue material the chrome ore forsterite SiOz) reaction with the added mag- nesia. insure complete conversion, THE IRON AGE, August 15, 1940—35 iy 7%, | é | rs 7 ‘ | cake — the amount magnesia added far more than theoretically required satisfy the silica present. This not surprising since only small propor- tion the added magnesia likely come contact with the gangue ma- terial. Volume stability “auto- property chrome-magnesite brick and has been variously attributed reaction between added magnesia and the gangue, solid solution mag- nesia the chromite, and replacement the FeO the chrome mag- nesia. all probability all these fac- tors play part. The all-basic furnace achieved one step. was only after chrome-magnesite brick its usefulness back walls, front walls, ports, etc., that the plunge was taken and complete furnaces (above the stage level) constructed basic refractories. Attempts have been made build open hearth furnace roofs with non-spall magnesite and forster- ite brick, but far the chrome-mag- nesite brick has given the couraging results. The Roof Success was first obtained with rela- tively small furnaces the Continent, most which were hard worked and were not shut off week-ends. The maintenance these small roofs was relatively easy matter and the ab- sence week-end shut-downs doubt- less reduced the amount spalling and thus helped achieve the remark- able lives obtained. experi- ments this country were less suc- cessful and was not until compara- tively recently that really encouraging results were obtained. the casual observer, the high chrome-magnesite silica price ratio might seem de- mand too great increase furnace life justify such trials, but those who have had experience with this type construction, and particularly those who, having got used it, have had return normal practice, real- ize that has many advantages besides long furnace life. Thus the use chrome-magnesite brick the back wall and roof results marked decrease the amount fettling re- quired and also much lower slag bulk due the absence silica drip. There little doubt that furnaces which are “all basic” except for the roof are also run much harder than the old silica furnaces, and that any return silica construction not only reduces the steady output per hour, but also greatly increases the amount shut-down time. The construction open hearth furnace roof with basic brick raises 36—THE IRON AGE, August 15, 1940 TABLE Analyses Basic Open Hearth Furnace Checker Dusts Air Gas Checker Dust; Checker Dust; Seven Samples Six Samples 48.3 39.3 FeO 0.0 0.2 CaO 13.6 MgO 4.1 MnO 1.8 1.2 SiO, 17.9 9.9 SO; 6.1 0.8 6.3 3.7 3.3 many problems not experienced with silica roofs. The thermal expansion silica above 1112 deg. very slight and hence the expansion silica roof much the same the outside the inside. With the chrome-magnesite brick, the other hand, which has approximately linear expansion curve, the expansion the outside probably about one- fifth that the inside. Such differential expansion cannot taken entirely lateral displacement. involves rotation effect—a much bigger expansion allowance being re- quired the inside than the out- side. Numerous ingenious attempts have been made overcome this diffi- culty, several them covered patent. Thus, suggested that addi- tion the usual skewback channels with adjustable coil springs take the load, tapered steel plates corrugated cross section inserted between the brick; the thick section the plate being the inside the roof. suggested that the roof heats the corrugations the inside ends flatten out while the outside the plate remains rigid; furthermore, that these expansion joints oxidize the inside and the scale thus formed helps weld the bricks together. Another suggestion the pivoting permit rotation addition lateral displacement. With large furnace such arrangement would require very complicated and expensive steel work construction above the furnace which might prove very difficult adjust. Such method would, how- ever, have the advantage that the roof would more likely keep its shape cooling because the rotation equip- ment would “go into reverse” and compensate for the bigger movement the inside the roof. More recently attempt has made give roof stability sus- pending alternate courses wires. The springing the skewback strain them reduced and the up- ward tension the roof tends minimize spalling that might have oc- curred due cracked brick insuffi- cient compression the roof. Since the hanger courses are than the others, the life the roof can extended filling the gaps with secondary brick soon the roof gets thin. The use this type construction requires special tap- ered roof blocks but view the great weight carried the fundamental difference expansion characteristics chrome-magnesite and silica brick, such radical changes may well prove necessary. The fact that one medium sized chrome-magnesite roof has now been service for over 1300 casts, whereas the earlier roofs built with similar brick only lasted about shows the progress that can made emploving the right technique. Tests Bricks great deal can learned from study the bricks that have al- ready proved their worth the roofs all-basic furnaces. Test data three bricks that have proved service- able are summarized Table I], to- gether with data one the in- ferior bricks recommended for back ing purposes. will seen that although the porosity these bricks moderately high their bulk density half great again that silica bricks, which rarely exceed 1.90 gm. and which more often only have bulk density 1.75 per c.c. clear that with large this difference bulk will require the use far stronger roof construction, quite apart the springing devices necessitated the different thermal teristics this material. CRUSHING Chrome-magnesite bricks erally crumbly compared with mag- nesite bricks, their strength frequently being low 1000 per sq. in. This weakness often leads damage brick edges during handling and hence poor joints the furnace brickwork. cold crushing strength least 2000 lb. per sq. in. therefore desirable. | | | | | PERMEABILITY The significance the permeability air still not very clear, but other things being equal, impervious brick preferable since will tend absorb less iron oxide from the fur- nace atmosphere than permeable one. With chrome-magnesite bricks meability 0.1 units not unusual. AFTER-EXPANSION Most chrome-magnesite bricks (un- like magnesite bricks) show slight viously stated, this expansion has been attributed number causes, but whatever the explanation very welcome since reduces the risk roof collapse. REFRACTORINESS Two principal methods are use this country for the determination refractoriness under load. (1) test piece (usually dimen- sions approximately in.) heated about deg. per min. under load Ib. per sq. in. until collapse occurs. The collapse tempera- ture and also the temperature which the expansion rate the system equalized the rate collapse the test piece, are noted. (2) similar test piece heated given temperature, usually per sq. in. and maintained this temperature for fixed period, usually hr. The per cent deformation after this the test piece noted. the first test the better chrome-magnesite bricks give fail temperature 3002 deg. (1650 deg. C.) more, while the second test collapse less than per cent after hr. 2912 deg. (25 per sq. in.) considered ade- quate for roof brick. practice most the load will which much lower temperature than the working face. With those ports which are not water cooled, the use brick high refractoriness under load essential. THERMAL SHOCK RESISTANCE: When test pieces dimensions 3x2x2 in. are sawed special chrome-magnesite bricks that show promise all-basic furnaces, and ex- posed given series thermal shocks, they are found withstand about reversals compared with only five for most and for straight American Society, 1989, Vol. 22, 97. Ceramic test used consists placing the cold test pieces furnace 1652 deg. F., leaving them there for min. and then placing them end cold brick floor. After min. cool- ing they are again placed the fur- nace and the cycle continued until the test piece can readily pulled apart the hands. The factors (in particu- lar grading) which contribute the production high thermal shock re- sistance, have already been discussed some detail earlier paper and will not therefore repeated BURSTING EXPANSION: Reference will made later the ultimate causes failure bricks the all-basic furnace. Suffice say here that absorption iron oxide from the furnace atmosphere leads serious expansion which eventually causes the spalling the bricks. This tendency can measured heating mill scale the surface the test piece (in the Central Research test 100 gm. scale are heated 3x2x2 in. test piece for hr. 2912 deg. and determining the sum the per cent expansions three di- rections right-angles. With some bricks this total expansion may amount much per cent, while with specially “doped” bricks may low per cent. Works trials show similar, not marked, difference the behavior the bricks. The data given Table show that the bricks now used have expansion about per cent. Microscopic microscopic and X-ray exam- ination suggests that the better bricks consist essentially 75-25 60-40 chrome-magnesite mixture the chrome occurs mainly coarse fraction and the magnesite mainly the fine fraction. addi- tion, there generally present con- siderable amount forsterite formed reaction between the gangue ma- terial and the magnesia. PROPERTIES: lot has been written concerning the low conductivity thermal chrome-magnesite bricks the work- ing temperature, and the possible fuel savings from the use all- basic furnace. Central Research tests, both the laboratory and the works, suggest that the heat losses are very similar those obtained with silica but markedly lower than those shown magnesite bricks. The thermal expansion chrome- magnesite bricks the order 0.9 per cent (68 deg. 1832 deg. F.) and this range essentially linear. With silica, equally great expan- sion obtained about 932 deg. and this should borne mind chrome-magnesite and silica bricks are bonded together. The specific heat magnesite brick very similar that silica brick and hence due the high bulk density the chrome- magnesite brick that naces have much higher heat ca- pacity. Note: Next week the author concludes this timely and informative article with data backing bricks, furnace life, factors determining furnace life, etc. TABLE Properties Chrome-Magnesite Brick Used All-Basic Furnaces Brick Brick Brick Brick (backing) Porosity, per cent 21.1 21.2 27.3 Bulk density, gm. per c.c. 2.90 3.13 3.00 2.84 Cold crushing strength, in. 2120 3460 3660 1560 Permeability air, perp. 9x3 in. face skin) ces. testpiece height (cm.) per sec. per sq. cm. per cm. water 0.030 0.045 0.016 0.077 After-expansion, 2hr., 2732 deg. 0.3 percent 0.3 percent percent 0.4 per cent Refractoriness under load: (a) per sq. in. Collapse rate expansion rate 2552 deg. 2606 deg. Fail temperature 3101 deg. 3002 deg. (b) per sq. in. Maintained collapse min. hour Per cent bursting expansion 23.6 17.4 35.8 Microscopic examination, approx. cr/mg ratio 75/25 75/25 60/40 75/25 Chrome size mm. 2mm. Magnesite size Very fine Very fine THE IRON AGE, August 1940—37 ~ 3 | | 1 > ‘ | + | ¥ all generating processes for fin- ishing the surfaces the sides gear teeth, the tool and the gener- ating machine should thought representing imaginary generating gear which rolled with the gear pinion being generated. bevel gear generation usual methods, the gen- erating gear itself bevel gear and has conical pitch surface. some cases, the pitch cone may flat and the pitch surface plane, that the generating gear then true degree crown gear. The imaginary generating bevel gear may even internal. Tooth Surfaces For practical reasons, the tooth sur- faces generating gear are sur- faces kind which can obtained straight bevel gear teeth are generated tools having straight cutting edges and reciprocated with straight-line mo- tion. The tooth surfaces the gen- erating gears are then oblique planes. Spiral bevel teeth are generated most- the Gleason spiral cutter, which 38—THE IRON AGE, August 1940 represents tooth the generating gear. Here the tooth surface general surface revolution, and straight cutting edges are every point the tooth surface generated gear, there one corre- sponding point the tooth surface the generating gear. considering variations the tooth surfaces cor- responding points, have about the most direct way understanding the requirements obtain desired results gear cutting. Conjugate Bevel Gears earlier times, bevel gear and pinion were always thought both being conjugate basic crown gear which could complementary self. The proper tooth surface for given bevel gear bevel pinion then was the surface conjugate gen- erated the tooth the imaginary basic crown gear. When oblique teeth came considered, however, with right-hand and left-hand directions, the two basic crown gears were longer identical, but would still fit to- gether with coinciding tooth surfaces. present methods cutting spiral bevel gears, the generating gears are not exact crown gears, but instead ALLAN CANDEE Gleason Works may external and internal gears with and tooth surfaces, indicated Fig. apparent general that any gear generated from generating gear other gear generated from generating gear Furthermore, any pinion gen- erated from generating gear instance, will conjugate gear the case what are known formate bevel gears. Tooth Contact Surfaces which roll against one an- other the manner gear teeth may contact only single point, and best can contact tangentially only line curve any one instant. Co- inciding surfaces are course impos- sible. Two spiral gear teeth, there- fore, theoretically touch each other along curved line ‘contact the gears rotate, the line contact changes position and sweeps over the whole active surface tooth. Tooth Bearing have the tooth contact modified slight- ly, that kept away from the boundaries the tooth surfaces, thus preventing concentrations load the tops ends the teeth. this kind contact found generally result smoother and quieter op- eration. The portion the tooth sur- face which actually has contact when gears are run known the tooth bearing. Tooth bearings can read- ily observed painting the teeth lightly with gear marking com- pound, and running the gears for few seconds. The tooth bearing one the moet comprehensive and direct dem- ov An ot Ao w A o> qre | ) Bearings onstrations the quality ofa pair gears When set ready run. The tooth bearing test gives in- formation regard such features the following: (a) surface smoothness, quality cutting, grinding, shaving, lapping (b) uniformity teeth, accuracy spacing, run-out, position contact, pressure angle, spiral angle, correctness assembly (d) amount contact, curvatures tooth surfaces (e) character contact, variations different points tooth Tooth bearings change relative position gear and pinion changed. Unsatisfactory ings may result from inaccuracies manufacture assembly, and also from changes due heat treatment. bevel gears customary make allowances for the deflections which cone Internal generating gear (B) evel Gears... the first part this article, which was abstracted from paper read the annual meeting the American Gear Manufacturers Association Asheville, C., May 22, the author presents some fundamental conceptions gearing and proceeds analyze the various factors governing the amount and location the tooth bearing area straight and spiral bevel gears. the second and concluding part the article will show how small displacements from the correct relative position gear and pinion affect the tooth bearing. occur under load. The tooth bearing bevel gears can changed using different tools and different modifications are almost always made the pinion, because has fewer teeth cut recut, and because responds more readily control mea- sures, Amount Tooth Bearing considering how desired tooth ally necessary think only the pinion, which changes are made. There are two conceptions adopt this work: The first the tween pinion having complete, 100 per cent tooth bearing with the given gear, and second pinion having the kind localized tooth bearing de- sired. second conception the dif- ference the tooth surface between actual pinion having some kind tooth bearing and pinion having the kind tooth bearing desired. Thus, need consider only how make the slight changes from the sur- face have the surface want. The diagrams Fig. show how the amount tooth bearing con- Tooth bearing Line contact Tooth surface 2—The theoretical line contact any instant limited the boundaries the tooth surfaces, whereas the actual line contact limited the boundaries the tooth bearing (upper right) which never covers the whole surface the tooth. IG. generating gear teeth, the tool and generating machine may thought representing imaginary generating gear which rolled with the gear being cut. making spiral bevel gears present methods, the imaginary generat- ing gears may external internal gears with complementary surfaces. The pitch surfaces are respectively externa! and internal cones supplementary angles. The tooth surfaces are also cones, concave and convex, represented inside and outside edges the cutters. THE IRON AGE, August 15, ~ Fe | aut | a’ Cone 7 2 concave tooth surface cone convex tooth surface | --*" Ax Mismatch tooth profiles Mismatch tooth spirals trolled differences between surface curvatures produce less than theoretical contact. Position Tooth Bearing The diagrams Fig. show that modifications pressure angle and spiral angle result changes the position tooth bearings. and pinion necessarily have the same pressure angle and spiral angle the point the tooth surfaces where they are contact. Thus tooth bearing the middle the tooth surface proof positive that the pressure angle and spiral angle match for the position which the tooth bearing tained. difference change pressure angle will shift the tooth bearing either down the tooth pro- files. difference spiral angle will shift the tooth bearing towards one end the other. Direction and Shape Tooth Bearing Tooth bearings are not always “square” with the principal directions the tooth surfaces and are not al- ways regular outline. condition encountered generating spiral bevel gear teeth tooth bearing low one end and high the other. This has received the name bias tooth bear- ing. See Fig. The kind surface mismatch which results bias lustrated two tooth surfaces tangent each other along oblique line 40—THE IRON AGE, August 1940 3—The length tooth bearing the direction from end end the tooth affected the difference curvature mis- match the tooth spirals (upper). Width affected difference ture the tooth pro- files (middle). actual gears, the tooth bearings are modified both di- rections (lower). Combined mismatch contact, each side which the pro- files curve away slightly another. The relative position which bevel pinion and gear actually run subject various tolerances, deflec- tions, and displacements. There are manufacturing tolerances not only for the gears themselves, but also for the shafts, bearings, and housings. Some 4—The posi- tion tooth bear- ing spiral bevel gears affected changes pressure angle spiral angle. deflection always occurs Heat treatment causes distortions tooth surfaces and changes gear mensions. therefore important know the tooth bearing various relative displacements between two gears which run together. the simplest case straight gears with completely conjugate teeth form corresponding involute spur gears, small variation angle the bevel gears would corre spond variation center distance spur gears and would not affect the tooth bearing any noticeable extent. Any other relative tween the bevel gear and pinion, how- ever, will affect the tooth bearing change spiral angle pressure angle, both. Vertical Displacement Spiral Teeth Fig. for instance, diagram (a) indicates the condition when straight tooth pinion displaced downward shown. Diagram (b) shows that when the gear then rotated restore contact with the pinion, the tooth surfaces illustrated will touch only their outer ends. The amount downward displacement shown enormously exaggerated, but the rela- matter how small the displacement may actually be. Spiral bevel teeth can much less sensitive than straight teeth such relative displacements. Diagrams (a) and (b) Fig. show the general Pressure angle and spiral angle the pinion match the angles the gear Pressure angle / Length ! ° ° A 4 Pressure angle too small ° ° ° | Out | Spiral angle ngle © Spiral angle too large Fishtail 5—The kind surface mismatch that results bias tooth Diamond tra bearing mating spiral bevel gears can corrected pinion generation changes machine settings that can directly cal- 7—Spiral bevel teeth are much less sensitive displacement culated. Less common are diamond and fishtail tooth bearings, which can corrected trial and error. effect spiral teeth downward displacement the pinion. Instead the tooth bearing being shifted the extreme ends the teeth, shifted outward only part way from the cen- ter. Horizontal Displacement This difference action due prin- cipally the fact that the teeth have somewhat different amounts curva- ture, although the general position the center curvature also im- portant factor. has customary cut spiral teeth with the than the convex surfaces, that with radial mismatch. Some this mis- match occurs naturally from the radial differences between outside and inside cutting edges the cutter blades, and any desired amount mismatch can had adjusting cutter diameters. The relation between mismatch sur- face curvatures and displacement tooth bearings three dimensional problem and requires consideration pressure angle and profile shape complete analysis. Probably from the beginning 8—Displacement the pinion along its axis principally causes slight change pres- sure angle. point the tooth sur- faces. the pinion displaced horizontally the left, some point relation the gear, the teeth will touch only their ends and oppositely the two sides. transverse Straight years, when the pinion displaced ver- (B) Spiral teeth with mismatch the pinion vertically. Tooth bearing shifted only part way the ends teeth because different tooth curvatures. the pinion will brought into contact with point the gear. Point M:, how- ever, has the same pressure angle point below point the pinion, that is, smaller pressure angle. The horizontal displacement the pinion from there- fore, has the effect decreasing the pressure angle the pinion with respect that the and produces shift the tooth bearing upward the pinion profile. Compore with Fig. bevel-gear cutting, displacement pinion along its axis has been used cause slight changes pressure angle. This may referred horizontal displacement, because the positions the testing machines customarily built. The principal effect relative horizonal displacement gear and pinion the kind illus- trated Fig. for change pressure angle. diagram show the geom- etry this change given Fig. These changes are not “pure” nature. bevel gears higher ratios, the horizontal relative displace- ment affects principally the pressure angle, but also has effect spiral angle, although this proportionally much smaller. The vertical relative displacement affects principally the spiral angle but also has slight effect pressure angle. miter gears and gears only low ratio, the amount the effect horizontal displace- ment the direction one axis, about the same the direction the other axis. (To THE IRON AGE, August 15, = Bias — rae (A) STRONG trend tooth spline drives for aircraft fuel pumps and other accesso- ries driven off the motor good example how commercial requirements have assisted military aviation. With air liners stepping operating time, some doing high 300 hr. per month the air, service requirements parts have become stricter, and are now accruing the the military. Pump Engineering Service Corp., Cleveland, one producer prominent the change from square and tongue drives during the past two years. This concern produces fuel draulic pumps, air pumps for flight instruments and air pumps for de- icer overshoes, all requiring degree accuracy. milling slot for its drives the company first tried mill one cut, but then found that two cuts least would necessary for accuracy, and even then the job lacked desirable aspects. The production setup was altered provide roughing cut followed hardening the part and finish grind. The result was satisfactory job, but still with the tongue driving two corners rapid wear resulted. studying the spline drive, which offers more points contact, Pump Engineering Service Corp. believed costs would creased and production problems mul- tiplied. Upon actual adoption, how- ever, the spline drive required less effort hold the parts accurate and percentage rejections were lessened. 42—THE IRON AGE, August 1940 type aricraft fuel pump rotor and drive coupling, made Pump En- gineering Service Corp., Cleveland. Use floating universal block take misalinement was unnecessary. The shaft simply floats. Fellows gear shaper generates the male spline. Broaching the female part involves important design job enable pulling the broach clear through the piece. The chordal thick- ness the spline tooth held example the accuracy re- quired for aircraft accessories, the rotor shaft journal diameter 0.6867 parable tolerances are held mating bearings. The company broaches fuel pump slots, too, well the splines. For- merly the slots were finished hand filing. The broaching the slots done Model 2-L Lapointe. Nitralloy steel used for nearly all hardened parts due the low dis- tortion encountered heat treatment. gears, after grinding the blanks and cutting the teeth, the part bur- nished, nitrided, and then the journals and faces are ground. Lapping the gear tooth contour the next opera- tion. spite the fact that aircraft pre- cision and quantities will not permit the use production methods, the company straight line factory routing high degree the last two years, and has installed much new equipment. This has enabled them keep pace with the rapidly increasing demand for air- craft accessories. All rotors magnafluxed. The completed pumps are put through extensive tests and record kept the acceptance test data each article shipped. Pump covers die cast aluminum alloy are being used experimentally the company. Several unexpected difficulties have been encountered here, but believed that the selection the proper material, together with the use extremely high pressures dur- ing the die casting process, will give satisfactory results. addition, the complete line pumps manufactured the company, also specializes hydraulic equip- ment for aircraft. This includes tuating cylinders for operating land- ing gear and flap gear, hydraulic ac- cumulators, and various types high pressure hydraulic valves. interest note that the aircraft indus- try general has recently turned hydraulic control, this dependable source power offers considerable savings weight over that encoun- tered with electric power, according aircraft designers the major airplane companies. Some the new products recently developed the company are diameter screwed type spherical which assures uniform flow two ac- tuating cylinders, and hydraulic flow control valve which limits the maxi- mum rate flow without causing any pressure loss low flow rates. { } personnel administration have emphasized the neces- sity some method weigh- ing the various human fac- tors employees and determining more accurately than mere impressions just how valuable each employee his particular work. This article presents very useful data this important sub- ject. ATING of employees, sometimes known merit rating, has be- come very popular late, al- many years various attempts have been made classify the different hu- man factors and reduce them math- ematical terms one man could placed above another relation value the company. This management tool has assumed greater importance recent vears be- Previously man could promoted fired when pleased the boss, who depended largely impressions the individual. Now that collective bargaining the order the day, concern must have more tangible evidence than gen- eral impressions. must set down paper anything comes challenge the manage- EUGENE CALDWELL Consulting Management Engineer, Milwaukee decision, definite the factors which the was will available. Regardless whatever else may charged against the movement to- ward collective bargaining, the efforts definitely rate employees one good that has come out it. organized baseball every act individual recorded, and the management knows exactly mathematical percentages the value each player the team. very essential industry that accurate gages developed deter- mine each worth the business. Not only there need get away from general impressions workers collective bargaining procedures but management should have accurate gages employees for many other purposes. The following tabulates the necessity emplovee rating from va- rious standpoints (1) justify actions which may later challenged before the national state labor board. (2) explain and justify actions with local union plant grievance committee. (3) supply accurate information for personnel control the part themselves. The uses made emplovee ratings addition those which are obvious from the tabulation above might listed follows: (1) For wage and salary adminis- tration. (2) determine persons eligible for promotion. (3) determine individuals retained case layoffs. (4) establish factors provided many seniority clauses. (5) determine all men are placed the best advantage the respective jobs available. (6) eliminate favoritism the part the supervisory force and as- sist impartiality dealing with the men. (7) create better attitude the part the workmen, pointing out his weaknesses and giving him some- thing work toward. starting out with employee rat- ing sharp distinction should made between employee rating and job rat- ing. They both work together but are two separate and distinct management tools. Job rating attempts rate the vari- ous jobs establishment indepen- dent the man who occupying the job. this means rates can set each job depending upon its worth the company and without consider- ing personalities. rate band can set for each job above below the ideal rate, and from this point the employee rating should govern the wage rates. the rating the em- ployee occupying the job low, then the employee should within the hourly rate band for the job but THE IRON AGE, August 15, 1940—43 4 Fal Ws | ° a | = ae. ° ° | | 2 | | — the lowest point that band. the employee ratings show the has increased abilities, his hourly rate should increased until the top the band. Remaining the top the hourly rate band for any time would indicate that should promoted the next higher job the job rating soon vacancy occurs. Almost everyone personnel industry has one time another attempted set some scheme for judging the human qualities the workmen. The vari- ous factors making individual per- sonalities are very intangible and their worth given job very controversial. Practically every qual- ity personality has some small bear- ing individual’s worth com- pany. When attempt made pick out certain factors larly evaluate one factor against another, the investigator enters the field pure opinion regarding which each person has different belief and upon which each passes different judg- ment. Rating Systems Analyzed list every attribute upon which judgment individual’s worth company could passed would tabulate all the adjectives the dictionary applied human per- sonality behavior. The writer has made extended analysis dif- many different companies. This analy- sis indicates that separate factors have been determined being im- portant enough for recording each em- ployee’s position with respect it. There follows tabulation the different factors used the rating plans analyzed. The factors appear the order their popularity except that closely related items are grouped together. Counted together one item are only those factors which appear the writer exactly synonymous. Any adjective having even slightly dif- ferent meaning listed separate item but related and immediately following the list. The figures after each item indicate the number rating plans which the particu- lar item appeared. Attitude, team work, Deportment, obedience, conduct Manner ....... Dependability, reliability, sponsibility Physical condition, health 44—THE IRON AGE, August 1940 Industry, effort, energy, steady worker, use working time ....... Speed, promptness Supervision required Adaptability, job Intelligence, intellect, thinking, mental, Job knowledge Knowledge sales plans Ability learn, ease learning, use Character, Ready fight, control emotions, self Completing assignments, follow through habit, perseverance, patience Effectiveness Original contributions, in- Adequate reports, ‘clear expression, cor- respondence Education Leadership Late, punctuality Quits ahead time Attendance Drinking Planning, systematic, methodical Vision Resourceful Debts, financial, Teaching ability Enthusiasm Self-confidence, self reliant, courage Social Sympathetic Friendly Timid Cheerful Conceit Courtesy Prejudice Analytical ability Logical Future development, potential value Tact Memory Able follow oral directions Alert Energy, endurance, vitality rn Profit criticism Sensitive ......... Training Imagination Stock subscriber Able follow written directions Intuitive Will power Loyalty Self-analysis Maturity Sense humor Wasteful Practical Ambitious Concentration Sales ability Observing This analysis shows that determi- nation the attitude was deemed essential practically all the rating plans. His dependability Was next importance followed physical condition, and quality and quantity work produced. The rating systems analyzed might segregated into two classes fol- lows: (1) Those that record cerning employee and impressions his personality. (2) Those that attempt grade worth his job and apply mathematical ratings this worth. The systems the first class use are generally quite lengthy volved. Some have listed many ad- jectives describing personality sort check list with the thought suggesting phrases which would de- scribe individual. Unfortunately, most these have not been worked out very logical manner, there being considerable duplication not only the use phrases having identical meanings but few instances repeating the same word again an- other place the rating several rating systems were unique mostly qualities, perhaps with the thought that negative characteristics could spotted more easily than positive ones. Rating systems the first type may some value recording facts and personality impressions for new applicant for new employee short- after comes with the company. Few these facts impressions change except over long period time, and hence there little use making periodic ratings this type. Moreover they not lend themselves comparison one employee with another. general impression can 4 | | | NEITZEL MANUFACTURING Milwaukee, Wis. NAME DEPARTMENT OCCUPATION EMPLOYEE RATING DATE RATED CHECKED BY DEGREE Form PR-6 CLOCK NUMBER ATTITUDE OPENMINDEDNESS. DEPORTMENT. CONDUCT. DISPOSITION. TEAM WORK. WILLINGNESS COOPERATE IN CARRYING OUT COMPANY POLICIES. OPINION TOWARD COMPANY GENERAL. DEPENDABILITY IN YOUR CONFIDENCE THAT EMPLOYEE WILL CARRY OUT INSTRUCTIONS. AC- CEPTS RESPONSIBILITY. RELIABLE FOR TICKLISH JOBS. QUALITY ACCURACY WORK. WORKMANSHIP. MEETING ESTABLISHED STANDARDS. FREEDOM FROM ERRORS. INDUSTRY EFFORT AND ENERGY PUT FORTH. USE WORKING TIME. STEADINESS WORK. SPEED AND PROMPTNESS. FOR WORKERS NOT INCENTIVE, RE- CORD THE OUTPUT SATISFACTORY ADAPTABILITY CHANGED CONDITIONS. EASE WITH WHICH NEW DUTIES ARE LEARNED. KNOWLEDGE KNOWLEDGE JOB. GENERAL KNOWLEDGE BENEFIT COM- PANY. KNOWLEDGE COMPANY POLICIES, PRODUCTS, AND OTHER DE- TECHNICAL ABILITY. POINT SCORE ATTITUDE ADAPTABILITY KNOWLEDGE | | | } | TOTAL OUTSTANDING IN CO-OP- ERATION. GOES OUT OF HIS WAY IN WORKING WITH OTHERS. ANXIOUS TO TRY OUT NEW IDEAS. OUTSTANDING ABILITY FOLLOW THROUGH. YOU HAVE UTMOST CON- FIDENCE YOU WILL GET WHAT YOU ASK FOR PROMPTLY. MAKES PRACTICALLY MECHANIC, HANDLES JOBS REQUIRING HIGHEST ACCURACY. EXCEPTIONALLY FAST. NEV- RESTS. OUTPUT UN- OUTSTANDING ABILITY PICK NEW JOBS. MEETS CHANGED CONDI- TIONS QUICKLY AND EASILY. EXPERT HIS JOB. KNOWS MANY OTHER JOBS AND GENERALLY WELL IN- FORMED. MEETS OTHERS HALF WAY. CO OPERATES WELL. WILI- ING TO TRY OUT NEW IDEAS. COMPANY BOOSTER. FOLLOWS INSTRUCTIONS CAREFULLY. REQUIRES LIT- | TLE FOLLOW UP. WILLING TO ACCEPT RESPONSIBILITY. SELDOM MAKES DOES HIGH GRADE WORK USUAL TOLERANCES. WORKS HARD AND STEADY. USUALLY DOES MORE THAN EXPECTED. FAST. ADJUSTS HIMSELF WELL GIVEN LITTLE TIME. LITTLE INSTRUCTION. GOOD HIS JOB AND SELDOM NEEDS GOOD KNOWLEDGE OTHER USUALLY COOPERATES. SOME RELUCTANCE SUGGESTIONS AND NEW IDEAS. ENTHUSI- ASM TOWARD COMPANY. USUALLY FOLLOWS IN- STRUCTIONS BUT NEEDS SOME FOLLOW-UP. SHIRKS RESPONSIBILITY. WORK USUALLY PASSABLE. OCCASIONALLY MUST JOB OVER. NORMAL AMOUNT ERRORS. TURNS OUT REQUIRED WORK BUT SELDOM MORE. RESTS FREQUENTLY. AVER- AGE SPEED. ROUTINE WORKER. RE- QUIRES DETAILED INSTRUC- TIONS FOR NEW JOB. ONLY FAIR LEARNING. KNOWS JOB FAIRLY BUT OTHER WORK. OF- TEN REQUIRES SUPERVISION AND INSTRUCTION. NOT WRITE BELOW THIS LINE ATTENDANCE NIGHT SCHOOL LATE ABSENT FREQUENTLY HEALTH SAFETY RECORD | | | COOPERATES ONLY WHEN HAS TO. WILL NOT FOL- LOW SUGGESTIONS. LITTLE INTEREST WORK. BAD INFLUENCE OTHERS. REQUIRES FREQUENT CHECKING, EVEN PLE TASKS. REFUSES SPONSIBILITY. CARELESS. JUST GETS BY. FREQUENT MISTAKES. CAN- NOT ASSIGN ACCURATE OUTPUT BELOW STANDARD. SLOW AND FREQUENTLY KILLS TIME. REQUIRES REPEATED IN- STRUCTIONS. SLOW LEARN. NEVER ADJUSTS NEW CONDITIONS ONLY WITH DIFFICULTY. LIMITED KNOWLEDGE JOB. REQUIRES MORE EX- PERIENCE. DEDUCTIONS ACCOUNT DATA FROM OTHER RECORDS POINTS POINTS POINTS FINANCIAL CLASS POINTS PIECE WORK (ADJUST “INDUSTRY” RATING PLUS OR MINUS) NET DEDUCTIONS RECORD ANY COMMENTS THE BACK FINAL SCORE NUMERICAL STANDING POINTS POINTS POINTS POINTS rating form has eight degrees for each the items. Since they progress from left right, pretty clear general impression the worth employee can gained observing how far the right most the check marks are. THE IRON AGE, August 15, 1940—45 company when such ratings for num- ber individuals are hand. Certain Criticisms Rating systems use the second might criticized the standpoint that some factors cluded the rating made the foreman supervisor where there better source information for that particular point, tor example, the ac- tual records the hospital first aid room are better evidence em- safety habits than the opinion the foreman. The same true health condition, which can best determined physical aminat