1942: Mechanical Engineering

Every mechanical industry has been materially affected by the war. Either the volume of product has been greatly increased, the kind of work has been changed, or the plant has been taken over for entirely new products. The extent to which it has contributed to the war effort has depended on the equipment available or the management, largely the latter.

The war emergency has shown that real mechanics can adapt many machines to uses for which they were never intended, while men accustomed to having special machines for every job have waited for new equipment to be built. We shall never know how much time has been lost in this way or how much material and labor have gone into machines that need never have been built. Frequently this was due to lack of broad vision on the part of production men. But in some cases, at least, new machines were demanded because of their value to the plant after the war.

In other instances machine tools, both old and new, have been and are being run at considerably below their real production capacity. While some of this can be laid to an ill-advised labor policy, most often it can be traced to inefficient management, which includes poorly planned flow of materials, slow procurement of tools, and other parts of the management program.

Some of the delay in the production of war supplies is due to unnecessary and unreasonable specifications as to materials, dimensional tolerances, and finish. Added to this has been inspection by inexperienced men who seem to feel that the more work they reject the better inspectors they are. This has resulted in the rejection of many parts that would have functioned perfectly in the completed product and opens up the disputed question of detailed specifications. Many good engineers contend that the purchaser of any product should specify the results he desires but no details as to construction except overall dimensions when the piece must fit some other member. In other words, specify results but not details.

One excellent argument for this practice is that in many cases specifications are drawn directly from machines already in use and thus prevent the acceptance of newer and better machines that have been designed and built since the original machine was constructed. This is mentioned because the present system of detailed specifications is depriving the armed forces of much good material at a time when it is badly needed.

Some of the conversions of large plants to war work involving an entirely different product have not been as satisfactory as anticipated. Even concerns which had been markedly successful in their own line of work have failed to get into production on war work nearly as rapidly as they had expected. While some of this delay has been due to not securing new and special equipment as rapidly as anticipated, the main reason for delay has been the failure of engineering and management to appreciate the intricacies of the new products and the differences between them and those to which they had been accustomed. This has been particularly true of the differences between the building of automobiles and airplanes and applies to both the planes themselves and the engines and other mechanisms, such as landing gears.

Instead of starting with the practices of the plane builders and improving them as experience proved feasible, all this previous experience was set aside in some cases and plans made for entirely new types of tooling and methods. This procedure is perhaps understandable in view of the great success attained in large automobile plants in securing unbelievable outputs of their own products. But the attempted transformation has been disappointing because of its failure to produce planes at the rate predicted and promised.

There is little doubt as to the final results of the entry of automobile engineers and management into the aircraft field. They are sure to be beneficial to both industries, and especially to the production of planes for the Allied Forces. Nor can the experience gained fail to be of lasting benefit to the cause of air transport for both commercial and private planes.

The delays should not be considered as reflecting on either the airplane or the automobile industries. The nature and uses of their products brought about very different rates of development. Airplane design, even in peace times, changes much more rapidly than automobile design, because engineers are dealing with forces and elements much less understood. Combat conditions bring changes even more rapidly, so that many builders are prepared to make changes after each 100 planes. The combined knowledge of the engineers of the two industries cannot fail to be extremely valuable to both.

While, as previously stated, there have been too many delays because of failure to utilize fully the possibilities of machine equipment already available, there have been outstanding examples where the output from existing plants far exceeded their expected quota. A notable instance is the case of a builder of automobile motors and parts who took a contract for a well known medium-horsepower radial engine used largely in tanks. Utilizing their old equipment to a remarkably large extent, they started production in record time. In addition to this they increased their output far beyond what had been considered possible and continued to turn out more and more engines as the months went by. This indicates the extent to which practical management affects output and enables the utilization of both men and machines not trained or designed for war work. The vision which enables a shop to adapt machinery to work of different kinds is a quality which makes production men valuable to themselves and to their employers.

While this ability to adapt to new conditions is particularly important in time of war, it may be equally so in time of peace. Sudden demand for planes, engines, or guns makes early production doubly valuable. A thousand planes a month in two months may be worth more than ten thousand a month a year later. There are also peacetime emergencies where a quick change-over in production may save the day for a manufacturer whose former market has been lost by a sudden change in design, in buying habits, or in tariff changes.

In a similar way the ability to utilize small shops on subcontract work has made it possible for many concerns to greatly increase the output of their products which are vital to the war effort. This has been true in such widely separated items as gyroscopes and milling machines. Here again the ability of management to adapt itself and its shop practices to meet changed conditions has meant much to both the firms themselves and the country at large.

Instead of making it difficult for the small shops by discouraging them at the start, as has been done in some cases, these concerns have helped the small-shop men tool up for the new jobs, have sent them their own skilled men to instruct new workers, and have relieved them of as much detailed bookkeeping as possible. One prime contractor has planned to utilize dozens of small shops equipped with only one or two machines apiece. Men are shown how certain work can be done on their machines. The parts then go to another shop for further operations. Some of the parts which must be heat-treated and tested for cracks with Magnaflux go to the parent shop for these operations and then go to other small shops for finishing operations.

It will be interesting to note the effect of this after the war. When a group of small shops have cooperated successfully it will be surprising if this experience does not affect their future business relations. It may well cause a trend toward continued cooperation and thus have a marked effect on many small industrial communities.

1941: Mechanical Engineering

Again machine development has been greatly influenced by the war but somewhat differently than in 1940. For while standard types and existing designs of machines are being used largely in the manufacture of various types of munitions, there has been real development along a number of lines. Special lathes for shell work, new machines for use in making gears, thread grinders and new adaptations of broaching machines have been brought out in addition to producing an unusually large number of standard machines.

Equally important perhaps, was the entry of firms new to machine building into that field. While much of this has been through the contracting of work by well known builders of machine tools in order to meet the ever increasing demand for their machines, machine tools are being built by concerns who formerly made other types of machinery, and in some cases old machine tool concerns that had ceased manufacturing are trying to recover some of their lost trade.

The Office of Production Management has encouraged the building of well-known designs of machines by firms entirely outside the machine tool field. One of the General Motors Corp. plants, for example, is building planers from patterns and designs furnished by an old builder of these machines. Other types of machine tools are being built by plants which formerly built printing presses, hoisting machinery and other diverse lines.

Probably the most striking example of increased production is to be found in the machine tool field itself. Nominally a small industry with an output of $145,000,000 in 1938, and employing about 20,000 men, it has steadily increased production until in 1941 the value will probably approach $750,000,000, and give employment to 100,000 men in the builders' own shops. This is in addition to the thousands of men at work on machine tools in other plants which are making parts or even complete machines on contract in other shops.

Normally an industry with a limited output that prevented the economical use of some of its own best products, expansion of the machine tool industry has not been easy. And a few of the best known builders whose output was never large have been backward in increasing their production to meet the requirements of defense. On the other hand some of the more progressive concerns have done a marvelous job in increasing their output. They have not only enlarged their own plants but they have trained enough additional mechanics to run these plants in two and three shifts. This utilizes the productive capacity of their own machine tools and permits them to send more of their product to the shops on defense work instead of using it to increase their own capacity.

In addition these concerns are utilizing the capacity of many other shops not normally building machine tools, to supply them with individual parts or even complete sub-assemblies of their machines. This not only greatly increases the output of machine tools but it provides work for many shops which might otherwise be idle through lack of demand for their regular product or difficulty in securing the necessary material.

The demand for defense materials has also developed centers of co-operation in industrial districts which should have an effect of stabilizing industry after the emergency is over. A shining example of this is to be found in what has come to be known as the York plan, because the machine shops in and around York, Pa., pooled their machine building capacity, and under very able leadership have become a most important factor in the production of defense materials. Contracts which none of them could handle alone were taken collectively. Work was distributed among the various shops in accord with their capacity and the result has been most gratifying.

Another activity that has been greatly stimulated by the increased need for machine tools is the rebuilding or reconditioning of machines that have seen much service in various shops. Under the stress of war time demand for really good machines the rebuilding industry has become thoroughly recognized as a very legitimate part of the machine tool industry itself. Government specifications as to what constitutes a really rebuilt machine has, with the hearty co-operation of the best rebuilders, eliminated the risk of getting a machine on which the only work done was to wipe off the grease and apply a new coat of paint. No machine can be sold today as being rebuilt which has not received a specified amount of work of specified quality.

As now rebuilt in some of the better shops machine tools that have been built from 20 to 40 years can be made capable of producing great quantities of much needed machine work. With better spindles and bearings, better gears, the beds planed and scraped and with modern electric motors added, many machines have been infinitely improved over what they were when first built. Small motors added for rapid traverse relieves the operator of labor that was considered part of the job when the machine was built. This does not mean that they are equal to modern machines of the same type. But rebuilding gives them many useful production hours at a time when new machine tools cannot be obtained.

One example is that of a 36-inch lathe with a 20-foot bed which was lengthened to 100 feet by adding four more 20-foot sections. At the same time the mechanism of the lathe was rebuilt and motorized, and the lathe is now turning propeller shafting in on the large ship building plants.

Shortage of vital materials has led to priorities, which conserve them for the uses where they are most needed. There have been interesting developments in aviation and in ship building, some details of which are not public property at present. So that in all walks of industry the present world conflict is having a marked effect.

1940: Mechanical Engineering

In 1940 there were fewer striking developments in machinery and in engineering generally than for several years past. This was undoubtedly due largely to the war, which has demanded large quantities of war materials of many kinds rather than the development of new devices. Perhaps the main development has been the utilization of machine building capacity already in existence to avoid loss of time and to avoid the building of new plants that may not be needed after the war is over.

Machinery for the making of munitions of all kinds has received careful attention, but much of it has been a revamping of the machines used in 1915 to 1918, as the work to be done has not changed materially. Better materials in the way of castings for the bodies or frames, better steels for the shafting, gears and driving members, better bearings and improved cutting materials, have all played their part in securing increased production.

Machine tools, as is always the case, are the bottleneck when greatly increased production becomes necessary. This has led to the adoption by some wide awake builders of the plan long used by the automobile builders, of having parts of their machines built in outside factories. A few have carried this to greater extremes than were believed possible, but with very good results. In most cases the complete assembly of the machine is done in the plant of the builder, who is responsible for its performance. This 'farming out' of work has been done to a much greater extent than ever before and has made for a greater utilization of the machine resources of the country.

The great demand for airplanes, guns and munitions has led to evolving methods of speeding their production. Plane builders are adopting more and more the 'farming out' method. In several sections where airplane plants are located a systematic survey of existing facilities has been made and tabulated. These facilities have been made available to all manufacturers and have helped to make increased output possible, and to spread employment without unduly disturbing housing facilities. The great accuracy required in the building of aircraft engines and similar parts has made the task difficult. But outputs have been materially increased by this method although not as yet to the desired extent. Airplane construction has, however, been stepped up considerably, particularly in the production of training planes and small planes for private use. One builder of small planes has been able to introduce line production methods and so greatly increase his output.

Air transport also has forged ahead, particularly in the matter of transoceanic flying. The Clipper ships to Europe and the Philippines are performing an invaluable service at a time when ocean travel is extremely hazardous. New routes are being tried out, particularly to link us more closely with our South American neighbors. (See also AVIATION.)

Machine tool builders have been busier than ever in their history, supplying Great Britain, and France before her collapse, as well as the great demands of our own country. Few new tools have been developed, however, except for shell work and other munitions. These are for the most part modifications of machines built for similar work for the last war, with the addition of hydraulic feeds in some cases. For hydraulic feeds and other movements are growing in use on machine tools, even on the smaller sizes. The hydraulic clutch, or 'fluid fly-wheel,' is also making its way in the automobile field. It is very simple, being merely a vaned impeller, a mating member connected to the drive shaft, both enclosed in an oil-tight case. It provides a very flexible connection between the engine and the rear wheels. It is not new, experimental work dating back at least twenty years in this country. It gives a very smooth start and is easy on tires. A recent application of hydraulics is a device to raise and lower the windows in high-priced automobiles.

One problem of demand for shell and other machinery is to keep it as simple as possible so that its operation can be taught to men and women who have never before handled machinery of any kind. This works in favor of the single purpose machine rather than the more highly developed and more universal machines that can perform many operations at a single setting. Shell work, too, has brought out the advantages of the high speed steels for removing large quantities of metal as is necessary in this work. With heavy simple machines it is easier to take heavy cuts and coarse feeds at a slower rate of speed than to use the carbide tools with high speeds and light cuts.

Another advantage of the simple machine is that it can be built in shops not familiar with, or equipped for, building machine tools of the more complicated types. This view is being held by the War Department, which has plans for extremely simple shell lathes, modified since the last war to meet present conditions. It has also a complete set of suggestions as to methods, speeds and feeds and depth of cuts. In addition it has tabulations as to the number of machines needed to turn out a given number of shells per hour of the various sizes likely to be needed, up to and including 16-inch projectiles.

The growth of furnace brazing for the joining of many metal parts has made possible the redesigning of many parts in a way that simplifies their manufacture. By this method several simple parts can be joined into one unit that would be very complicated if made in one piece.

New materials and new uses for older ones continue to appear. Stainless steel, for example, is widening its fields of usefulness in the air, in the new light-weight streamlined trains, and in marine work as well. Blades for steam turbines take more of this comparatively high-priced metal than many realize. In navy and coast patrol planes, stainless steel is used extensively in ribs, spars and for the covering of the fuselage. One of its advantages is that it can be joined by shot welding without materially reducing its strength. This gives it a marked advantage over duralumin, which must be carefully riveted with heat treated rivets.

Experiments with formed plastic sheets for aircraft continue to attract attention but have not yet gone into real production. They seem to offer possibilities for more rapid production of the plane fuselage and wings than any other method. The success of this method would be a great forward step in many ways.

New applications of the control of machines by light waves, known as the 'electric eye,' continue to be made. In one recent machine the light beam is used to detect, and reject, paper stock that does not come up to specifications. In this modern machine for making envelopes, a defective envelope blank, one that has a thin spot or other flaw, permits enough light to pass through to stop the machine. In other machines the light beam is used to operate relays which control hydraulic valves that, in turn, control powerful mechanisms.

Until the war is over and we again turn our attention to peacetime pursuits, engineering energy must be directed toward the making of implements of destruction. Development of devices to improve normal living must of necessity remain in the background.

1938: Mechanical Engineering

High Spots of the Year.

Engineering progress is seldom spectacular. It is usually a growth based on practice or discoveries that have gone before. Perhaps the most noteworthy of 1938 developments is what is known as super-finish, a method of obtaining metal surfaces with fewer defects than heretofore. Yet this is a development of the process known as honing, which has been in common use for some years. The method and the results obtained will be mentioned later.

In a similar manner, local hardening of steel parts, both by the use of flames and by electrical current, have found new fields of application. Hydraulic control of machine movements has resulted in wider applications in lathes, planers, and other machine tools. This now includes the movement both of the work and of the tools. Ingenious mechanisms provide constant or varying speeds and feeds, by either automatic or manual control. Hydraulics have also made their way into a standard automobile in this country for the first time in regular production — the custom built Chrysler Imperial so-called fluid flywheel, built under British patents.

New materials, both metallic and otherwise, have made their way into the manufacturing industries. Newer steels, which with proper heat treatment replace some of those higher in cost, as well as rust-resisting steels that can be machined much more readily than formerly, make possible more durable products at lower costs. New cast alloys are replacing forgings in crank shafts and cane shafts. New Plastics, that are more stable under atmospheric changes and have other desirable properties, and a new synthetic rubber by the DuPonts are all advances that have helped industry. While the new rubber lacks some of the qualities of the natural, it has others that are superior for some industrial uses. New mechanical processes also are coming to the front.

Superfinish.

Superfinish is an outstanding development by D. A. Wallace, President of the Chrysler division of the Chrysler Corporation. It is a refinement of the honing process, made possible by the discovery that speed, pressure, and direction of movement play an important part in obtaining the best surface for reducing wear between metals in contact. This combination differs materially from previous practices in honing. But while the machinery employed is expensive, the desired results are secured at very low cost.

The production of superfinish requires at least three motions between the work and the abrasive stones, and five or more motions frequently give better results. Some machines have as many as ten motions; and some have a multi-motion action, so that the abrasives literally scrub the metal surfaces to a crystalline smoothness.

Other finished surfaces present a series of high and low spots about equally divided. Superfinish removes the high spots and leaves a flat or smooth surface between any minute scratches that may be left below the surface. These scratches are but from one to three millionths of an inch deep.

While the surface superfinished resembles a mirror, the real object is to make it possible to retain an unbroken film of oil between bearing surfaces and so increase the load-carrying capacity, or to increase the wear life with the same load. Used as a finish, this method does not appreciably change the dimensions of the work unless the tolerance is less than 0.0005 inch. It is possible however to obtain the same finish and remove as much as 0.001 inch at the same time. Abrasive stones of from 180 to 500 grit are used, and no extra-fine preliminary finish is required. The superfinished surface is had in from 3 to 30 seconds with a pressure of from a few ounces to a few pounds per square inch of stone area.

Flame Hardening.

Flame hardening has come to the fore as a commercial practice in the hardening of gear teeth and, to some extent, in the hardening of flat surfaces. An early application was the hardening of gear teeth in steel automobile flywheels before separate ring gears were used for this purpose. This was done by heating each tooth separately and rolling it into a hardening bath. The modern method is to have a stream of cooling water just behind the torch to cool the surface immediately. This is largely used in hardening the teeth of large gears which cannot be heated all over, as in the case of small gears.

Another modern application is the hardening of the wearing surfaces of the bed of a lathe, or ways, as they are usually called. This has been developed by the Monarch Machine Tool Company for their lathe beds, to greatly reduce wear and prolong life. The lathe bed is partly submerged in a tank of water, while the heating torches are moved over the surface by a suitable mechanism and at the proper rate. The water from the cooling nozzle follows, as in the case of gear teeth, and cools the bed behind the nozzles. Keeping the bed submerged reduces the distortion to a minimum, the few thousandths of an inch that interfere with perfect alignment being removed by an accurate surface grinding machine.

Somewhat similar results in local hardening are obtained by what is known as the Tocco process. This is being used for hardening the wearing surfaces of crankshafts and camshafts for automobile motors. The method provides for the local heating of the surfaces by electrical contact pieces and the cooling of the piece by flooding as soon as the proper heat has been reached. The effect is quite comparable to flame hardening.

Increased Accuracy in Machine Work.

The increasing demand for greater accuracy in machined parts leads to constantly changing methods in shop practice. This increased accuracy gives us machines that perform more satisfactorily and have longer life. Where a few years ago a thousandth of an inch was considered a fine measurement, we now demand and receive parts made to within a ten-thousandth of an inch of the ideal dimension, and occasionally even split 'tenths' on very fine work. This has been made possible by more accurate machine tools and by new and improved methods of making very fine measurements.

New instruments make it possible to measure defects in the quality of a surface to a millionth of an inch, which opens up a new field in the smoothness of machined parts. We have heretofore had no measure of the quality of a finish that did not depend on judgment of the inspector. The new instrument measures the depth of any defect in the surface and shows the frequency with which these defects occur. The Bureau of Standards has shown that the wear of gages in use depends more on the smoothness of the finish than on the hardness of the steel. It is this quality that makes the new superfinish particularly valuable, as it greatly increases the wear life of parts finished by this process.

The demand for accuracy has led to the abandonment of the use of jigs and fixtures in the machining of some types of machines. For while jigs and fixtures are necessary to secure duplicate work without the use of highly skilled mechanics, it has been found that greater accuracy can be secured by the use of the jig-boring type of machine, with a single-point cutter and a highly skilled mechanic. With the relation of bored holes located by very accurate screws, micrometer dials, and measuring rods, the holes can be bored more accurately than with the average fixture which holds the work and guides the boring bar. Then, too, the single-point tool can do more accurate work than the usual boring cutter. Strangely enough, the jig-boring machine, which was designed to bore holes in jigs, has made jigs unnecessary in many kinds of work.

However, this new use of jig borers in manufacturing would not have been practicable but for the development of the cemented carbide tools which have replaced steel for work of this kind. These tools are almost as hard as the diamond and can be used over long periods without re-sharpening or resetting. They maintain their cutting quality in machining large numbers of holes, which is not only economical but insures the different holes being of the same size. If the tool point wore appreciably while in use, the holes would not be alike and might even be smaller at the end than at the beginning of the cut. This illustrates the manner in which one development makes possible other improvements that could not be utilized previously.

Changing Methods.

Shop methods are constantly changing. Planing gave way to milling in production shops. Milling is being rivaled by grinding and broaching, yet is staging an attempted comeback in the field of turning, which formerly belonged to the lathe. Machines for machining round work by rotating it in front of a milling cutter, and in one instance a revolving broach, are replacing the turning machine in some cases. Honing machines replaced cylinder grinders in automobile shops and are now themselves threatened by the superlinishing machines.

One well known engineer suggests that we may see the grinding machine eliminated from cylindrical work, where it now holds almost complete sway. He feels that we may turn round work sufficiently accurate with carbide tools so that it can go direct to the superfinishing machine and be ready for assembly. While all predictions are dangerous, the many changes that have taken place in machine development and in methods should prepare us for further drastic changes in the near future.