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IN a discussion of the difficulties that are being overcome in converting automotive plants to the production of war equipment with virtually no new machine tools, Mr. Geschelin emphasizes the difference between the production requirements of an automobile engine and a modern airplane engine by pointing out that: The connecting rod of the Allison airplane engine requires 93 operations compared with 25 for the Cadillac passenger-car engine; the Allison crankshaft requires 80 operations, the Cadillac crankshaft 62; and the Allison cylinder block has 17 pieces compared with a single block for the Cadillac engine. After calling production know-how, “the major contribution of the automotive industry,” Mr. Geschelin draws attention to the fact that the automotive industry also is largely responsible for bringing American production machinery to its present high state of development.

AUTOMOTIVE ordnance, Major-Gen. Wesson states, covers generally automotive weapons-motor vehicles used primarily as fighting machines in battle and hence equipped with guns and protective armor plate. He notes particularly that it is a special and non-commercial phase of automotive engineering. After describing the mission, personnel, means, and procedure of the Ordnance Department, the author traces the development of the tank since 1918 and contrasts the modern 10-ton tank, which uses about 250 hp to propel it at speeds up to 45 mph while carrying a “payload” of armor, guns, ammunition, men, and equipment amounting to from 30% to 40% of its gross weight, with a 10-ton commercial tractor. He explains that, when producing a tank, the Ordnance Department uses, wherever possible, commercially available components. When this cannot be done, he noted, a modification of a commercial component is used and, as a last resort, a specially designed ordnance unit is used.

DEVELOPMENT of cast camshafts at the Campbell, Wyant & Cannon Foundry Co., starting in 1924, proceeded slowly until a material was developed that met all requirements from metallurgical, engineering, and manufacturing standpoints. “Proferall,” the name given this material, means processed-ferrous-alloyed iron made by the duplexed-electric-furnace process. Camshafts of this material have a Brinell hardness of 262-293, as cast. A series of tests, equivalent to runs of 46,560 miles, showed that both chemical analysis and hardness affect camshaft-gear wear. Comparative wear tests on bearings showed more than three times as much wear on steel camshafts as cast ones. Other tests showed the cast shafts expanded less than those of steel. After describing foundry processes the paper concludes by summing up the advantages of cast camshafts, such as the smaller cost of patterns as compared with forging dies and the elimination of heat-treating, copper plating, carburizing, and hardening.

This paper is confined to a discussion of machine-shop operations, and is intended to indicate by a few examples certain important economies that might be introduced in the shops of the automotive industry. It deals chiefly with the economies that can be effected without much capital outlay, though others are also mentioned. Calling attention particularly to the fact that, in the past, improvements of methods and of equipment have been confined largely to the more important operations on the more important parts and that relatively little study has been made of the smaller pieces and the less important operations, emphasis is placed on the necessity for carefully determining which tools and which makes of tool will best serve the purposes for which they are intended and for carefully sharpening the tools and providing means of setting them accurately.

The author describes the progress of the work of artillery motorization in the year 1920, beginning this with a statement of the recommendations made by the Westervelt Board, appointed by the War Department to make a study of the subject, for the development of track-laying equipment, the use of wheeled trailers on which the track laying materiel could be loaded and towed over good roads by trucks, and in regard to the possibility of incorporating trailer wheels in the track-laying vehicles themselves. The various types of materiel constructed during 1920 are illustrated, described and commented upon, inclusive of heavy tractors, supply and maintenance equipment, gun-mounts and tanks. It is stated that the recommendations of the Westervelt Board will be the basis of armament development for some time to come.

Motorization, as developed during the war, is stated as the greatest single advance in military engineering since the fourteenth century. Excepting about 66 per cent of the 77-mm. guns in the combat division, all mobile weapons of the United States artillery are motorized and complete motorization has been approved. The history of artillery motorization is sketched and a tabulation given of the general mechanical development in artillery motor equipment to May, 1919. Caterpillar vehicle characteristics are next considered in detail, followed by ten specifically stated problems of design which are then discussed. Five primary factors affecting quantity production, successful construction and effective design, in applying the caterpillar tractor to military purposes, are then stated and commented upon. A table shows specifications of engines used by the Ordnance Department and three general specifications for replacing present engine equipment are made.

The necessity for a powerful heavy-duty truck with power transmitted through all four wheels was apparent shortly after the United States became involved in the war. An intensive study of the four-wheel-drive situation finally resulted in the design of the Ordnance four-wheel-drive truck and the modified form known as the artillery wheeled tractor. Seven factors influencing the preparation of the specifications are stated and discussed. The determination of proper gear ratios is analyzed. The considerations leading to the adoption of the universal-joint type of driving-shaft are mentioned and its application commented upon. Ten specific points of internal interchangeability of the mechanism are enumerated.

THE author presents a brief description of the design of some of the principal vehicles used in motorizing the artillery, as developed by the Ordnance Department. A few of the vehicles are described, including gun mounts that were being developed at the time of the signing of the armistice. The relative merits of the different types of equipment are discussed.

THE track-laying type of vehicle is, of course, old. The emergency which brought the modern “tank” into existence was the menace of the machine-gun. The tank is simply a device that can approach closely and destroy the gun or its crew. It is fundamentally a man killer, and its strongest points are speed and mobility. It is now an indispensable arm of the military service. The writer gives a rapid résumé of the fantastic period in design, the early work done on heavy armored cars and the reasons for concentrating on the track-laying type of vehicle. The American type of track was adopted as a foundation and from this and around it France, England and the United States have developed the tanks known through successful use in the war. The British are to be credited with producing the first practical fighting machine of this type. France has two types of machine, one mechanically driven and the other with electric drive, both small.