The Iron Age 1945-04-12: Vol 155 Iss 15

Editorial and Advertising Offices 100 East 42nd St., New York N.Y., U.S.A. IRON AGE Vol. 155, No. April 12, 1945 VAN DEVENTER President and Editorial Director BAUR Vice-President General Manager LEONARD Assistant General Manager HAYES Advertising Manager JOHNSON, Manager Reader Service and Market Research BAUR, Production Manager CLEARY, Technical Research and Promotion Manager Editorial Jobs for Baby Snooks and Grandpa Technical Articles PEIRCE WARREN Spot Welding Magnesium Alloys (Part II) RAYMOND KAY Los Angeles New Equipment 2420 Cheremoya Ave. ° ° ° ° ° Owned and Published CHILTON COMPANY Features OFFICERS AND DIRECTORS EVERIT TERHUNE Vice-President FAHRENDORF Vice-President WILLIAM BARBER, Treasurer News and Markets BUZBY THOMAS KANE West Indies Laborers Imported 112 Member, Associated Business Papers Machine Tool Market 146. Nonferrous Metals News and Prices Iron and Steel Scrap News and Comparison Prices Week and Year ustria rts x. . . ° ° Copyright 1945, Company | i] | | | } | | | | | — Firth-Sterling’s Star-Mo M-2 displays all the advantages looked for modern high-speed steel for general use. out-classes the old traditional steels all important points: out-cuts and out-lasts, assuring bigger, more consistent production; performs with ease. All this lower cost. wonder Star-Mo M-2 wins the acclaim ever-growing list tool makers and automotive manufacturers. They know head- liner when they see one perform. Your shop will convinced too with Star-Mo M-2 workout. outcuts and outlasts approximately 20% less STEEL ask our representative 50—THE IRON AGE, April 12, 1945 STAR-MO M-2 SS ESTABLISHED 1855 ° Editorial Staff Editor ......... OLIVER Commercial Associate Editors WINTERS JOHN ANTHONY BARMASEL Assistants MILLER HANSEN April 12, 1945 VAN President and Editorial BAUR DAVIS Regional News and Technical LLOYD Pittsburgh 428 Park Bidg. POST Bidg. MOFFETT DONALD BROWNE EUGENE HARDY Washington Bidg. LLOYD Cleveland 1016 Guardian Bidg. BRAMS Detroit OSGOOD MURDOCK Francisco 1355 Market Editorial ROBERT Cincinnati DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS St. JAMES DOUGLAS Jobs for Baby Snooks and Grandpa has not yet been officially proclaimed that the world owes you living but our government has declared that acknowledges its responsibility seeing that you get chance earn one. This the so-called “full employment principle.” effect says that every one able and willing work should have jobs, and that private employers and private individuals cannot make for million persons, then the government will create enough additional ones complete the round number. Most economists agree that full employment our country postwar days highly desirable from everybody’s standpoint. More than per cent our total purchasing power comes from wages. When employment good, then business good for industry, farmers, railroads, shopkeepers and everybody else including beauty parlors and thirst quenching emporiums. There small but powerful minority that won’t happy unless the government called upon make the greatest possible number these postwar jobs and indeed would like have make them all. But most believe that the fewer jobs that government has make keep the employment pot boiling, the better. That because jobs created private employers are “self-liquidating” and pay their way, whereas government jobs, depending taxation for support, waylay the pay. Only two ways can government make jobs: One out current income receipts; the other out debt. time war, expect government call upon debt order make jobs. But government, even for the past years, has not made job without calling debt help finance it. War merely accentuated the positive which this case was the minus sign the negative. Unless look forward postwar repudiation our national debt and that means the end war bonds, bank-notes, savings accounts and life insurance policy equities, the time must come—and soon—when national income must equal, least, national expenditures. Admitting this, how then can government create jobs and still keep solvent? There are but two ways. One raising the taxes levied those employed high enough level take care the unemployed. That means the general lowering the standard living. The other way distribute employment reducing, law, the working hours per week. Inasmuch cannot consume more than make, this obviously another method reducing the standard living. could probably keep everyone working full time, for example, even with double our present working population, had hour week. But straying from title. Maybe Baby Snooks and Grandpa have been included that mystical figure million who will need postwar jobs. Who knows? know that one bird the hand private enterprise worth two the bushes bureaucracy. | | | | | | Spheroid Another Wartime Use Inland Steel Guarding America’s great harbors small Navy within the Navy men and tenders who handle the antisubmarine and antitorpedo nets. These nets, often more than two miles long, are supported spheroid floats. great number these floats, which are in. diam- eter, are made welding together preformed segments that are cut from Inland plates. The plates shipped for this purpose Inland not only measure specifications, but they are delivered assuring uninterrupted production, low manufacturing cost, and on-time delivery floats the Army and the Navy. Meeting customers’ manufacturing schedules Inland tradition, which have done our best maintain even the face the heavy demands and changing needs wartime pro- duction. This principle punctuality begins when order taken—and follows through the order department, the metallurgical depart- ment, Inland’s modern mills, and the traffic department. Inland, every order calls not only for high uniform quality but for cooper- ative service well. When you need steel invite you call Inland. Strip Tin Plate Bars Plates Floor Plate Structurals Piling Rails Track Accessories Reinforcing Bars INLAND STEEL COMPANY Dearborn St., Chicago Ill. Offices: Cincinnati Detroit Indianapolis Kansas City Milwaukee New York St.Louis April try first auto liais direc trole quart the amour cred: I this } News Front Salvaged war materials are being disposed the Allies Italy try that country. The purposes the plan are twofold, get rid the material without shipping the S., and nourish economically starved Italian industries. Despite the absence publicity, raids England continued the invasion upper Holland, with average about civilians killed and about fifty injured every day. Shaving aircraft gears, which only year ago was limited only one small gear, has now been extended approximately different gear types. Experiments conducted the Wright Aeronautical Corp. proved that gears designed with the intention finish grinding after hardening are equally well suited for shaving before hardening. Other gears tested Wright included gears which could not: ground but which had sufficient axial clearance for Gear shaving offers several advantages including time saving, uniformity gear tool elements and size, accuracy independent the operator and simplicity operation. However, machines must carefully set and heat treatment must rules for automotive reconversion were set WPB Chairman Krug series conferences between major automotive executives and WPB officials. date for automotive production will not set, nor will quotas issued until after V-E day. Although the actual go-ahead may come shortly thereafter, all production which will follow European victory will subordinate Pacific war needs. Present planning foresees the production 2,150,000 cars the first year production. handle questions involving machine tools, materials and tooling, for the auto industry with the Production Readjustment Committee and other agencies liaison office has been created Detroit under the direction Henry Nelson, director the WPB Aircraft division. ‘In the first quarter after day about 1,500,000 tons carbon steel and 264,000 tons alloy steel will released for such essential programs troleum production, public utilities, railroad and the container industry. For the military services, this per cent reduction carbon steel requirements and per cent reduction alloy steel needs. Thereafter, carbon steel requirements will reduced per cent for the next two succeeding quarters; the cutback alloy steel for the second quarter cent, and the third quarter per cent. Cutbacks for the fourth quarter after day will amount per cent for carbon steel and per cent for alloy steel. Price fixing and international quota agreements may have retained the British steel industry according recent statements the London Times. Some the problems facing the British steelmakers are the comparatively high prices coal and iron ore. Development helicopter which can carry five passengers any type equivalent load going forward Bell Aircraft, although the craft has not yet flown. Designed specifically for commercial jobs embodies design innovations credited Arthur Young well two and half years flight experience two experimental craft. reports, Pittsburgh Steel Foundry Corp., Glassport, Pa., ne- gotiating consolidation with Pittsburgh Spring and Steel Co. Mechanical shell loading equipment being installed the Ravenna Ordnance center that should save millions manhours labor per year continued operation. Machine tool builders are giving much attention postwar public relations connected with the introduction machines period threatening unemployment. large scale selling program planned counteract this stigma. . i q | | | | | | } HAVING method finish- ing gear teeth was developed high degree perfection the automotive industry. The ex- perience thus gained was based high production operation, steels suited these particular require- ments and heat treating procedures developed for these particular steels. The problem faced the producers aircraft engine gears, con- siderable measure, was quite contrary the experience and practice vogue for shaved gears intended for automotive use. Aircraft engine gears are completely different de- sign and operation requirements. has been the accepted practice practically throughout the industry finish grind all aircraft engine gears after hardening where design permitted. This practice could not abandoned without considerable development and testing, the result which predicated entirely new. approach before gears could produced production basis. For aircraft engine gears weight and space are vital factors and re- sult gear blanks extremely light web sections, non-uniform distribu- tion material and the minimum. diameter possible. addition, speci- fications established for case and core hardness must strictly adhered well dimensional tolerances, all For descriptions initial applications shaving aircraft gears, the reader referred the article, “Shaved Aircraft Gears,” Ivan Calicoat and Curt Payntor the Studebaker Aviation Di- vision, Fort Wayne, IRON Dec. 16, 1943, 44; also “Shaved Gears Chevrolet Motor Division General 58. See also “Manufacture Aircraft rar, Wright Aeronautical Corp., THE TRON Dec. 24, 1942, 29. 54—THE IRON AGE, April 12, 1945 aa which are subjected close and complete inspection. Gears designed with the intention finish grinding after hardening are equally well suited for shaving. Among the others were gears which could not ground but allowed sufficient clearance for shaving and few which required design changes permit shaving. determine what the possibilities were shaving these various types aircraft engine gears, program considerable extent and scope was decided upon and established. Many experiments were necessary, many sample lots gears were shaved and heat treated verify the correctness and control the procedure estab- lished, and much engine testing was necessary prove the value and equality the change manufac- turing process. result was found that gears designed with the intention finish grinding after hardening are equally well suited for shaving before hardening. Other gears tested included gears which could not ground but which had sufficient axial clearance for shaving and gears that were redesigned permit shaving. Today approximately different gears are being finish shaved production Wright Aeronautical Corp., Paterson, The follow- ing will describe how they are proc- essed. should noted here that any reference shaving refers the rotary type machine using the cross axis principle. Some the advantages gained finish shaving are well known and others may now included, fol- lows: Considerable time saved for the finishing operation and therefore higher production rate with fewer machines. Accuracy controlled shaving cutter and not dependent care operator. Uniformity gear tooth ele- ments and size. Simplicity shaving machine operation. Large production quantities per shaving cutter life. Uniform case thickness obtained with correct heat treatment. Partly offsetting these advantages are certain precautions that must maintained accurately possible and locating bore sizes held close limits. Pre-shaved gear teeth must cut accurately machines that are functioning correctly and are carefully set up. Care must exercised load- ing shaving machines avoid damage work cutter. Heat treatment must carried naces. Material must suitable hardness produce desired finish. Gears must carefully handled between finish shaved and hard- ened state. Another disadvantage that the shaving cutters can applied only limited range tooth numbers for the same pitch. should noted that items and apply any method finishing the gear teeth for accurate prepara- tion reduces errors that must cor- rected the final finishing operations. aircooled aircraft engines prac- tically all types gears are used with the major portion being spur gears. These include internal and external under the following category: Gears which can ground (Fig. large gear, Figs. and 14). Gears which cannot ground (Fig. small gear, Figs. and 18). Gears which are free quenched (Fig. 5). Gears which are die quenched (Figs. and 18). Obvi shavin the was cated are For alloy (or tute the requir the sui All erated pro has curate cut she tests fillet have failur sibilit devel and vario show chart amin the 0.000 fined centr sligh ally mast tion and ment | | | Engine shafts (Fig. 3). Gears clusters (Figs. and 9). Obviously, selections for the first shaving experiment were those with the most promising possibilities. This was then extended more compli- cated parts and finally gears which are die quenched. For all Wright Cyclone gears two types steel are used; namely, high alloy low carbon similar SAE 3310 (or the National Emergency substi- tute AMS 6260) and nitralloy. Each these steels reacts differently the required heat treatment, therefore the shaving tools have adjusted suit the type steel used. All pre-shaved gear teeth are gen- erated with protuberance type hobs shaper cutters which are designed produce the necessary undercut. has been found that this undercut absolutely essential produce ac- curately shaved gears. This under- cut was one the prime objections shaving but subsequent exhaustive tests have proved that the undercut fillet did not materially affect the load- carrying ability the gear teeth. date none the gears thus shaved have shown the least evidence failure. With all these restrictions and pos- sibilities mind and how they all developed actual production best shown few examples gears and the involute forms charted various stages production. Discussion Charts Fig. involute form and “Red Liner” chart the gear teeth part shown Fig. All teeth have been charted for involute form and ex- amination the chart will show that the total variation involute 0.0004 in. and that this error con- fined two three teeth. The con- centricity chart the right shows slightly under 0.001 in. runout. Actu- ally most this runout the master gear for with one full revolu- tion the gear and concentric and true master gear, the start and finish the chart must aline- ment. This chart quite representa- Gear Engineer, Wright Aeronautical Corp., Paterson, Any gear that can ground can shaved, whether free quenched die quenched, according the experience this air- craft engine producer. Many such gears are now being shaved production. Shaving also being done production cluster and internal gears which, because their shape, could not ground. Altogether, types gears are being shaved. succeeding article, carburizing and hardening procedures will described. tive the modification introduced when shaving carburized gear. Dur- ing heat treatment carburized gears have tendency change form reduction across the tip, therefore all such gears are shaved with heavy full involute form. This accomplished changing the pressure angle the pre-shaving and shaving cutters sufficient amount produce the desired modification. This part shaved from centers and with deg. cross axis. Fig. shows the involute form chart except that the latter has teeth, 12/18 pitch, deg. pressure angle while the chart for 15-tooth pinion 8.4 pitch, deg. P.A. This form not acceptable, defi- nite hollow has developed slightly above the pitch diameter.and change cross axis, the pre-shaved form, must made eliminate this condition. Fig. the involute form chart the external gear shown Figs. and The restricted clearance reduces the cross axis deg. and the resulting form produced con- siderably different, having definite high pitch diameter barrel form. Red Liner chart showed runout within 0.0015 in. Theoretically this gear should only contact the pitch diameter. Yet examination Fig. which shows the same gear after test, reveals the full and uniform bearing developed when operating under load, obviously not agree- ment with the measured form and definite indication gear movement and deflection under load. Fig. gives further illustration the change which takes place tooth form during carburizing and hardening. The hardened form and the shaved form Fortu- nately this change advan- tageous direction that minimizes fact that both gears this cluster are now shaved, where only the larger gear was previously ground (the smaller gear being finished shaping) indico- tive the progress made the adaptation this finishing process production. This die quenched part. THE IRON AGE, April 12, 1945—55 well | | | | i ; i ABOVE charts for the gear shown Fig. ° RIGHT 5—This planetary pinion was one the first gears shaved pro- charted Fig. except that has 12/18 pitch instead 8.4. tip interference under deflection loads. This particular chart the in- ternal gear Fig. The amount modification necessary produce the desired barrel form depends largely upon the size the gear teeth and established mainly experi- ence and trial. fair average 0.001 in. Fig. the involute form charts the various stages internal the pre-shaved state and the undercut 56—THE IRON AGE, April 12, 1945 ABOVE 3—Small gear in- tegral with spline shaft which charted Fig. © i ‘ RIGHT 1G. 4—The hollow de- veloped the invol- ute just above the pitch diameter makes this shaved gear unaccept- able. produeed the protuberance type shaper cutter. the finished shaved form shows clearly how the shaving cutter has straightened and corrected the involute form within very close limits. After nitriding, the true form change shown to. very slight. The deviation from the perpendicular line the char- acteristic evidence runout and the result grinding the locating diameter after hardening slightly ec- i j ; i i i quite evident that this lapping has not corrected the eccentricity and has produced 0.0001 error some the teeth. Nitralloy Gears Nitralloy steel has certain charac- teristics which require that such gears lapped after hardening. The pro- cedure outlined for the gear shown Fig. has been’ successfully used this and similar type gears. Some external gears smaller diameter and tooth numbers, however, have not | i i q if - o < a o Onn Refi Na. F ternal gear shown HARDENED ABOVE AND LEFT 8—Charts the Fig. Chart right for the green shaved gear; the left, same gear after hard- ening. aad definite high pitch diameter barrel shape charts the external gear shown ? i 4 i 4 3 in é ey | Be 4 | | A—Pre-shaved responded with equal success when made nitralloy steel and processed similar manner. general, most nitrided gears have only the gear teeth hardened which, therefore, localized and the supporting material cessive distortion. Also the fact that nitralloy requires low heat for the hardening process aids retaining its original form. The fact that cer- tain surface conditions exist which must removed after hardening makes less desirable for shaved gears, however. the major portion the gears used are carburized, one the first requisites that the gear teeth meet hardness specifications and are free from decarburization. insure that these specifications were maintained, improved method carburizing was developed Wright Aeronautical Corp. materials laboratory. This method carburizing and hardening one the contributing factors which has made the shaving air- craft engine gears possible and will 58—THE IRON AGE, April 12, 1945 B—Finished shaved Fig. the involute form taken during various stages production the internal ring gear shown Fig. dorfer Wright Aeronautical labora- tory succeeding article. Heat treat distortion usually found nor- mal and hardening pro- cedure also considerably reduced this method. Some shaving prac- tice rough cut, carburize, anneal, pre-shave cut, shave and harden. This procedure involves many additional operations which are unnecessary, as, with the proper and correct heat treat procedure, gears can finish shaved before carburizing, be- ing done Wright Aeronautical. some instances necessary anneal carburized parts for fur- ther machining. This procedure avoided whenever possible, merely another source decar- burization. Internal threading, drill- ing oil holes and machining notches, such shown Fig. 12, must neces- sarily the part before hardening. avoid decarburization, the part thoroughly cleaned and flash copper plated before being annealed. This also holds true for parts which are die quenched. These are thor- oughly cleaned after carburizing and C—Nitrided flash copper plated placed the hardening furnace. The type gear shown Fig. falls this category. The internal gear this cam cannot ground and has been successfully demonstrated that such gear can shaved advan- tage and the resulting product defi- nitely improved. The cam shown Fig. now shaved production well number other parts which require die quenching. Tooth Modifications Many the critical aircraft en- gine gears are actually tailored suit conditions developed engine operation. distribute tooth bear- ing under load often necessary incorporate definite taper the gear teeth. Fig. such case the teeth open end are smaller than the flange end equal about 0.002 in. tooth thickness. This gear nitralloy steel and shaved, hardened and lapped. the “sun” stationary gear the planetary drive which Fig. the shavec finally recent succes done Cro have did menta air taper showr lem Fro ver produ is, tain harde light low showr the b must ness. cor tion. eratio q D—Lapped the mating pinion. The latter shaved, carburized, hardened and finally grit blasted. This train has recently completed several severe tests successfully, but shaving not yet done production. Crowning elliptoid tooth forms have been attempted but the results did not warrant any further experi- mentation. general, the face width aircraft engine gears entirely too narrow take full advantage this feature. Where necessary definite taper tooth, such used for the gear shown Fig. 14, has solved the prob- lem misalinement under load. From the foregoing clear that very uniform and accurate gear produced the hardened state. is, therefcre, necessary main- tain this accuracy during and after hardening. Distortion controlled proper heat treating procedures. Carburized gear teeth are given light blast with very fine grit and low pressure. Gears such those shown Figs. and then have the bore honed size. the hone must follow the original path, close accuracy maintained and the only correction made for out round- ness. Thrust faces are then lapped complete the gear for inspec- tion. Where additional grinding op- erations are necessary, locating sur- added operation this internal nitralloy ring gear, charted Fig. 10. Shaving development still progress this gear, which drilling oil hole and machining notches must per- formed before the part 13—Shaving the internal gear added operation this thin webbed cam which has die quenched. face prepared honing and the subsequent operations held rela- tion such surface. arriving the cost shaving many other factors must consid- ered. Much experimenting often necessary establish the correct blank and shaving cutter combina- tion. Pre-shaving tools must cor- rect and carefully controlled. Locat- THE IRON AGE, April 12, 1945—59 | ad — q ing sizes must maintained within very close limits and some instances must honed the green insure proper fit arbors. Where smooth fillets are essential, gear teeth are rough hobbed, pre-shave cut with shaper cutter and then shaved. Uni- form stock must removed the shaving cutter and desirable reduce this permissible minimum. The importance accurate pre- shaved blanks cannot emphasized too highly, the shaving cutter has definite tendency follow the pre- shaved form, especially gears small diameter and tooth numbers. the final analysis the experi- ence with Wright Cyclone shaved gears service has fully justified the time and effort devoted the development. The outcome that shaved gears are being produced production basis which are uniform size and tooth form, have uniform case thickness all tooth surfaces, meet all specifications case and teeth this nitralloy sun gear are shaved with slight taper obtain proper tooth bearing under load. This shaving job still the experimental stage. core hardness with excellent grain structure, and perform with excep- tional ability engine operation. Finally word about gear grind- ing. There are still many gears which grinding will continue. The procedure outlined for shaved gears can also applied ground gears (that is, grinding the soft state), thus opening new field for its ap- plication which can and will remove some the inherent difficulties that result from grinding gears after hardening. There are applications for both methods and the important decision concerns which method will produce the best possible gear. [In succeeding article, the metal- lurgical aspects shaved aircraft gears the Wrigkt materials laboratory.} Dont Take Equipment Failures for Granted the second part his article, “Large Scale Working Adiron- dack Magnetites,” Frank Oliver makes statement page the Feb. 1945, issue THE IRON AGE that should not unchallenged. reads: “Maintenance the big item the crushing plant and the concen- trator mill. pure luck all the power shovels and trucks are operation once. the mill there are bottlenecks galore caused mechanical breakdowns, motor burns out the primary crusher, in. rubber belt begins tear apart the roller bearings get the sintering machine pallet conveyors.” safe say that the mechanical equipment preceded some human failure such as: Failure install equipment de- signed for that particular kind work Failure make operators equip- ment conscious Failure properly maintain that equipment. fact that modern equipment designed for the job, properly in- stalled and properly maintained will give continuous service with little interruption operation regard- 60—THE IRON AGE, April 12, 1945 GILBERT LINDGREN Electrical Maintenance Foreman, Troy Coke Plant, New York Power Light Co. less how severe that operation may be. This not say that good equip- ment never fails and that machines designed for rough service never wear out. What meant that there such thing necessary evil regards equipment failure. Where you find that equipment failures and the maintenance that equipment are interfering with pro- duction, you will also find lack interest the equipment itself and the methods handling maintenance problems. Where plant handi- capped obsolete unsuitable ma- chinery which cannot remodeled replaced, then attention focused the application mainte- nance rather than the machines. Such attention will bring light many changes that will lead far less operating interruptions. Years ago the steel mills, failures the screwdown drive blooming mills was considered necessary evil; these motors were subjected heavy overloads, severe plugging and reversing, stalling against jammed rolls, heat and dirt. mill used carry two three spare armatures. expected burnouts and had them; yet today such drives are put through the same paces and give little more trouble than any other drive. Im- provements have been made change regards neces- sary expected breakdowns. Too often taken for granted that severe operating conditions justify few shutdowns that burned out motor naturally means serious delay. Instead setting aside $1000 the budget take care motor rewinds, spend $500 prevent- ing motor rewinds and the following year you will find that you can reduce the $500 item. No! Mechanical electrical equip- ment failures are not necessary evil connected with severe industrial oper- ations. First, check your equipment then apply pressure scheduled inspection and repairs that are timed cause the least interruption operation. See that operators realize that just important keep machinery running run it. Make your mind that not pure luck unlucky when machines run fail run—it’s the human element that governs that, per cent the time. Interstat Corp., design riveting was mad 0.032 in. toa terial ext trailing rivets. giv aft surface complete area, the justable rail made floor. sign may ‘inder Time method the ope mad tubing, operat and the steel air ment | | en | | | 3 | | | | ° Yoke Riveter Reaches Inaccessible Places encountered the wing flap fabricating department the Interstate Aircraft Engineering Corp., Segundo, Calif., led the design and installation ingenious riveting fixture. Primarily this device was made for riveting top skin 0.032 in. gage 24S-T aluminum alloy in. rib flange 0.020 in. ma- terial extending from the spar the trailing edge the flap, distance in., using modified brazier head rivets. give the yoke riveter fore and aft movement along the contoured surface the rib flange and skin and complete coverage the wing flap area, the unit suspended ad- justable chain from trolley running rail which forms the cross arm swinging jib crane, the latter made pipe stand riveted the floor. Details the yoke riveter de- sign may seen the photographs. riveting operation ‘inder and toggle links. Time studies show that per increase was accom- plished comparison with the old method riveter and bucker. UPPER RIGHT method riveting and bucking contoured surface wing flap; two-man job, awkward and slow. With the new yoke riveter only one operator needed. CENTER XTENDED arm yoke riveter enables tremities job with ease. This model tubing, the upper being pivoted with re- spect the lower and brought into operating position the air cylinder and toggle link seen the left. Note the adjustable tilt table for conforma- tion with wing flap section contours. RIGHT length rivet arm permits ciose- work. This model utilizes flat steel plate for the base, but the same air actuated toggle for initial adjust- ment the yoke opening placing the rivet set position. Standard rivet guns are employed. & if? Chemistry Surface Cleaning Cleaning complex phenomenon involving various com- binations such actions wetting, emulsification, saponification, activity, solvent power, pH, buffer action, total alkalinity and acidity and water conditioning. Much the enormous amounts time and labor expended the removal the common forms dirt and paint can cut knowledge the basic factors involved each surface cleaning job. the layman, dirt self evi- dent and requires further explanation. the scientist, dirt complex chemical and physical components, with widely varying reactions under different cir- cumstances. The mere enumeration some the common forms dirt corrosion, tarnish, scale, oil, grease, carbon, grime, smut, paint— will give some indication the com- plexity the problem. All these them, may present any single ° me) ° action progress, cap- tured the high speed camera. mass heavy oil adheres firmly the bottom the beaker. Wetting action causes portion the oil rise the surface. SEE 62—THE IRON AGE, April 12, 1945 article requiring cleaning. un- derstanding, the chemical and physical nature the more fre- quently kinds dirt and the factors definitely associated with detergency may prove valuable the proper selection cleaning agent method designed remove dirt. Before surface can cleaned must first wetted the cleaning solution. Wetting action serves bring the detergent solution into close and intimate contact with the soil, enabling penetrate soil that the energy detergency can brought bear where most. surface which has been com- pletely wetted detergent fluid has been separated cleansing film from contaminating matter, and therefore well the way being cleaned. popularly believed that wet- ting action natural property Actually, liquids vary greatly their ability wet. Water, which has the reputation being the “wettest” substances, reality possesses much less wetting power than such familiar liquids am- monia, acetone, benzene and most oils. Fortunately for economy detergency, the wetting properties water can greatly increased chemical treatment. The wetting powers fluids can increased reducing their surface and. interfacial tensions. The force surface tension can demon- strated simple experiment. Fill RAY SANDERS General Manager, Turco Products, Inc., Los Angeles ° ° glass the rim with water. additional small amount water added, will not overflow but the surface the water the glass will form convex dome higher than the rim the glass. Surface tension keeps the water from overflowing. the force surface tension were re- duced, the water would overflow im- mediately. Pure water has much higher sur- face tension than most oils. When pure water poured oily sur- face, the surface tensions the oil and water resist each other with the result that the water unable spread over wet the oil film. In- stead, the water forms individual round drops pools with convex domes—a precise reflection the forces surface and interfacial ten- sions involved the situation. Now the surface tension the water that the oil film, will spread out over the oil film. Reduce the surface tension the water still further 2—A thousandth second later. The tension between the oil and water has been reduced cleaning agent. Large globules form the surface the oily mass. that the oil penetrat this occ surface droplets detachec the oily and its plete ting The oily ably str strated wiping cloth test. wetting that that formati surface the into pla present globules surface the cle: the perman tered cleaning tracted, 4 : | | | | | : that actually less than that the oil film, the water will then penetrate and displace the oil. When this occurs remarkable thing hap- pens—the oil forms droplets the surface the water film. These droplets may not yet completely detached from the soiled surface, but the oily mass has been penetrated and its adhesion weakened com- plete wetting. This process wet- ting illustrated Figs. 1-5. Emulsifying Power The forces cohesion which hold oily film surface are remark- ably strong. almost impossible completely remove oil film the shearing action wiping alone. This can- demon- strated for example, repeatedly wiping lard coated frying pan with cloth until more lard visible and then applying the water break test. Invariably, water will resist wetting such proving that oil film perhaps molecular dimension still remains. has been mentioned previously that thorough wetting results the formation globules oil the surface the detergent film. Here the process emulsification comes into play. emulsifying agent present the detergent, the oily globules will detached from the surface and will dispersed through the cleaning solution. The adhesion the oil the surface has been permanently disrupted. Once scat- tered the portion the oil removed 3—A large portion the oil has been detached and floats the top the cleaning solution. The oily mass has con- tracted, leaving the beaker bottom clean. cannot film. (See Fig 6). When portion the oily film has been removed this manner, another layer the film exposed the wetting action the detergent. Emulsifying action then comes into play again and disperses addi- tional portion the oily mass. can seen that emulsification con- tingent wetting and that further wetting contingent emulsifica- tion. The combined effect the two actions the loosening, breaking and dispersion oily films. Emulsions vary considerably their permanency. Some emulsifying agents form protective films around the oil droplets which prevent their coalescence with neighboring droplets. The resistance the emulsion breaking thereby increased. These are known permanent emul- sions since they endure for long periods without separation oil and medium. Milk familiar example stable emulsion. the case 4—The cleaning solution beginning penetrate beneath the oil. When oil and surface have been separated the cleaning solution, wetting action will have been completed. emulsifiers producing quick breaking emulsions, protective film pro- vided. Hence, surface tension causes the oil droplets coalesce whenever they touch each other. The droplets become larger and larger, ultimately forming continuous oily layer which floats the surface the medium. cleaner designed for use immersion tanks desirable that the emulsion produced the quick breaking type. After the bond be- tween the oily film and the surface broken and the oil dispersed that the surface the tank where may readily skimmed off. this man- ner the life the cleaning solution greatly increased. the other hand, cleaner designed for ap- plication wiping spraying, the emulsion produced should stable. Since the cleaner applied film over the surface quick breaking emulsion would tend redeposit oil over the surface being cleaned. stable emulsion the dispersed oil will remain suspension until rinsed away. The extent which oil emulsi- fied and the speed with which emulsi- fication takes place determined primarily the character and con- centration the cleaning agent em- ployed. The process furthered agitating, and some extent heat- ing the solution. The method which the cleaner applied, therefore, plays part oil removal through emul- sification action. The process emulsification does not produce chemical change the oil removed. The oil remains oil except that dispersed through- out the detergent medium the form very small globules. However, the process emulsification facilitates chemical reaction, saponification, which permits certain oils pass into actual solution the cleaning agent, Fig. Saponifying Value Saponification the process where- fatty acids present animal and vegetable oils unite chemically with 5—Finally the adhesion between oil and surface completely disrupted. Note remaining oil floating small droplets, THE IRON AGE, April 12, 1945—63 | ° ° | | certain alkaline substance form soap. The soap formed quite similar, not external appearance, household soap its chemical properties and behaviour. The re- moval fatty acid soils one the major problems detergency. Many greases consist mixture animal fats, such tallow, and petroleum oils. Petroleum oils cannot saponified and must, therefore, removed through the processes wetting and emulsification. But the fatty acid components lubricants react with certain alkaline deter- gents form water soluble soaps. The process soap formation has chain consequences vital im- portance the detergent reaction. begin with, considerable portion the soil made soluble the cleaning solution. The dissolved soap brings about further reduction the surface and interfacial tension the solution, and increases the emul- sifying action the detergent. turn, the process saponification further stimulated when additional fatty acid soil becomes available small droplets. The dissolved soap also has dispersing effect solid particles, and the concentration saponified material builds ciently may exert direct solvent effect oils and other substances ordinarily insoluble aqueous solu- tions. will seen that properly bal- anced cleaning compound exerts definite chain effect which one ac- tion reinforces the other and turn reinforced. The utilization the process saponification cleaning the soil itself pressed into service help the removal the remain- ing soil. Colloidal Activity colloid non-settling suspen- sion finely divided solid particles liquid medium. Materials which have the ability break solid mass into particles and dis- perse them through liquid are known deflocculating agents. The earliest detergent known, for an- tedating soaps and chemical deter- gents, fullers earth, highly col- loidal clay which possesses notable de- flocculating powers. Colloidal activity plays vital part the removal soils composed insoluble solid par- ticles. Carbon, clay, road film, food deposits and paint films are among the soils removed colloidal forces. The mechanism deflocculation 64—THE IRON AGE, April 12, 1945 6—An emulsifying agent added and the contents the beaker agitated stirring rod. The mass oil broken into tiny globules, uniformly dispersed through the water. ° ° ° believed involve the neutralization those forces surface tension re- sponsible for the attraction between solid particles. Experimental data re- veals that every instance defloccu- lation attendant upon reduction facial tensions involved. Complete wetting the solid, course, necessary initiate deflocculation. paragraph from the “Industrial Chemistry Colloidal and Amorphous Materials” Lewis, Squires and Broughton may serve illuminate the importance dispersing power detergency: “Perhaps the most important method (of testing the effectiveness fabric under controlled condi- tions mixture oil and car- bon black applied using vola- tile solvent, followed comparison samples after careful washing with the detergents under test, pref- erably using one known effec- tiveness standard. The im- portance dispersion power detergency attested the fact that the capacity the detergent cleanse such fabric parallels its power disperse suspended particles, such carbon manganese dioxide, iron oxide and the like water. The direct de- termination this dispersing power therefore offers second important testing method.” laboratory practice this test may amount Norite, highly absorptive activated carbon, test tube, add- ing given volume the detergent under test, and determining the length time required for the solu- tion completely wet the carbon and disperse it. Colloidal forces are important not only the direct dispersion solid particles but the softening and swelling resinous binders, which are factor the adhesion paints, enamels and similar coatings. Solvent Action Solvents may divided into two broad classifications. one group the dissolved substance splits more less completely into groups molecules called ions which possess definite electrical charges. Water the most familiar solvent this type. The solvent properties water are utilized cleaning remove many salts, acids, sugar and syrup deposits. aqueous cleaning solutions water also acts the solvent medium for the detergent compound, thereby liberating the energies which result wetting, emulsification, saponifica- tion and deflocculation soil. Be- sides its solvent qualities, water also acts dispersal medium for the oils and particles which will not dissolve, but which can made carry suspension. Further, serves means for the application heat energy and for applying the mechanical energy agitation, all which play part detergency. The chief limitation the ionizing solvents,-such water, detergent agents that they have solvent effect oils and greases. Such sol- vents are ‘described technically lipophobes (fat haters). Another approach the application solvent activity cleaning the use the second broad classification solvents which not split the sub- stances they dissolve into electrically charged groups molecules. Derived basically from petroleum, coal and wood, these solvents are unable dissolve many substances which are readily soluble water, but they possess the ability dissolve not only oils and greases but many resins, rubber, bitumins, parafine and waxes. One the fundamental advantages the organic solvents that they are capable formulation into detergent agents which are chemically neutral, that they offer method for the ‘safe cleaning reactive metals, such aluminum, magnesium, copper and Some deter; carbor bustion paints the orga carbon surfaces formed petroleur able dete tion solvents and hol similar moval insoluble bonding swelled, suitable Turco with emulsifyi and their out loss carbon sive laye the plications required process. sol trate break tire mags solvents either may the insoluble but will mixture. anced quired move the any surfa the degre water the energ alkali When certain groups cules cal hydrochlo splits chlorin the 4 4 3 7 Some the most difficult problems detergency, such the removal carbon deposits from internal com- bustion engines, and the stripping paints and enamels are assigned the organic solvents, such Turco Fuzee. The tenacious, intensely hard carbon deposits which form engine surfaces are held together resins formed during the combustion petroleum fuels (Fig. 8). avail- able detergent has direct solvent ac- tion carbon, but certain organic solvents are capable softening and dissolving the resins which bind the carbon particles together into masses and hold them the surface. similar situation exists the re- moval paint where the pigment insoluble, but where the resinous bonding agent may softened, swelled, dissolved the use suitable solvents, such those L-780. Use Organic Solvents Remarkable work has been done with organic solvents increase their emulsifying and penetrating power, and their ability absorb soil with- out loss cleaning power. Paint and are usually present succes- sive layers. the solvent active the upper layer only, repeated ap- plications prolonged immersion are required complete the removal process. Properly formulated, the or- gani¢ solvents can made pene- trate through successive coatings and break the bond which holds en- tire mags soil the work. curious phenomenon relating solvents that substance insoluble either two solvents individually may readily soluble mixture the two. Collodion, for example, insoluble either alcohol ether, but will dissolve ether-alcohol mixture. the same manner, bal- anced mixture detergents re- quired almost every instance re- move the complex soils found any surface requiring cleaning. and Its Control yardstick for measuring the degree alkalinity acidity the energy but not the amount alkali acid solution. When table salt dissolves water certain portion splits into groups electrically charged mole- cules called ions. Similarly, when hydrochloric acid dissolves water splits (dissociates) into groups chlorine and hydrogen ions. When the familiar alkali, sodium hydroxide, chemically changes the insoluble oil soluble soap. Note suds top beaker—evidence fur- ther reduction surface tension resulting from saponification. ° ° dissolves water yields sodium and ions. All acids share common the ability yield hydro- gen (H-) ions water solution. All alkalis yield hydroxyl (OH-) ions water solution. Alakalis and acids differ greatly, however, the num- ber hydroxy] hydrogen ions they release per given weight given volume water. fluid ounce per cent hydrochloric acid solution would yield far greater number hydrogen ions than fluid ounce per cent solution acetic acid. The acid which yields the greater num- ber hydrogen ions more ener- getic entering chemical unions with other substances, and described strong acid. The same distinction holds between strong and weak alkalis, except that the release hydroxyl ions responsible for the difference activity. may concluded, therefore, that the con- centration hydrogen hydroxyl ions determines the relative degree solution. expressing mathematically the con- centration hydrogen and ions given water solution. should remembered that ions are groups molecules, and that comparison with the total volume water their quantity ‘indeed very small. typical measure the con- centration hydrogen ions gram liter solution may result frac- tion like this: 1/10,000,000 Obviously would difficult deal practically with such very fractions. simplify the expression these values, scale was devised that based the logarithm the reciprocal hydrogen ion concentra- tion. Values arrived are known values and may arranged scale from 14, with the neutral point. Values above in- dicate degrees alkalinity, values below degrees acidity. Both alkalinity and acidity become more intense the values move away from the neutral point. Thus, repre- sents weak alkaline reaction, the other extreme, 1.5 would indicate strongly solution, while 13.5 would represent strongly alkaline solution. Each increment represents tenfold increase decrease acidity more acid than and 100 times more acid than and forth. Since method stating the concentration electrically charged groups molecules, the most ac- curate method measuring in- volves the use sensitive volt- meter which measures the potential across the charged ions, and registers this terms values. meter. Other means determining are available that are based color stances exposed alakaline acid solutions. These materials are called indicators, the most familiar being litmus. Litmus has little value determinations since does not yield definite and sharp color changes for step step increases either acidity a