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A grinding-machine for finishing spur-gears is illustrated and described; claims are made that it will grind transmission gears on a production basis after they have been heat-treated and will produce correct tooth-contour, smooth finish and accurate tooth-spacing, these features being necessary in producing gears that are interchangeable and that run quietly. This machine is of the generating type, its action being that of rolling a gear along an imaginary rack and using the grinding wheel as one tooth of the rack. The dished grinding-wheel is reversible, 30 in. in diameter, mounted below the gear, and can be swiveled to the right or left of the center position up to an angle of 25 deg. The work-spindle carries the indexing and the generating mechanisms at the rear, where they are accessible and yet are protected.

To install conveyors in a going automobile manufacturing plant of moderate size, without interrupting production, and with a minimum amount of rearrangement of the plant and an investment commensurate with the saving to be effected, was the problem, the solution of which is herein described. The conditions that determined whether power-driven or gravity-actuated conveyors should be used are discussed and the various types required for handling raw stock, for machining operations, for sub-assemblies and for finished assemblies are indicated.

Annual Meeting and Detroit Section Paper - As the success or failure of the finish of an automobile depends largely on the finishing-varnish, a plea is made for more scientific analyses of the problems of automobile finishing and more care in selecting and applying a suitable varnish. The qualities to be desired in a finishing-varnish are divided into two classes: the shop qualities and the service qualities. The shop qualities include color, body or viscosity, working, flowing, setting, hardening, fullness and the safety of working. The service qualities, or those that enable the varnish to withstand the various conditions of use, include resistance to break-down under the chemical action of the actinic rays of sunlight, to the destructive action of moisture and the alkalis in mud and soap, to expansion and contraction, to vibration and to abrasion.

The author states briefly the phenomenal growth of taxicab usage and consequent demand for this type of motor vehicle, mentioned the differences in body requirements for taxicabs as compared with those of passenger cars, and describes the methods used to secure durability in taxicab-body construction to discount the severe service to which the body is subjected. Tabular data are presented and comments made regarding the woods that are suitable for body framework, and the methods of joining frame members and reinforcing frame joints are outlined. The desirable types of roof and the factors that influence design are discussed at some length, illustrations being presented also, and minor considerations, such as types of hardware, dash and instrument-boards, are included. A brief summary states present conditions, and a bibliographical list is appended of informative publications relating to the subject.

Annual Meeting Paper - The heat-dissipating properties of three types of radiator core have been investigated at the Mason Laboratory, Yale University. These include the fin-and-tube, the ribbon and the air-tube groups, so classified according to the flow of the water and the air. The ratio of the cooling surface to the volume is shown to be nearly the same in the fin-and-tube and the air-tube cores, while that of the ribbon core is somewhat greater. A formula is derived for computing the heat-transfer coefficient, which is defined as the number of heat units per hour that will pass from one square foot of surface per degree of temperature-difference between the air and the water and is the key to radiator performance, as by it almost any desired information can be obtained. When the heat-transfer coefficients have been found for a sufficiently wide range of water and air-flows the cooling capacity of a radiator can be computed for any desired condition.

The different gear noises are classified under the names of knock, rattle, growl, hum and sing, and these are discussed at some length, examples of defects that cause noise being given and a device for checking tooth spacing being illustrated and described. An instrument for analyzing tooth-forms that produce these different noises is illustrated and described. Causes of the errors in gears may be in the hardening process, in the cutting machines or in the cutters. A hobbing machine is used as an example and its possibilities for error are commented upon. Tooth-forms are illustrated and treated briefly, and the hardening of gears and the grinding of gear-tooth forms are given similar attention.

The process devised by the author was evolved to eliminate the difficulties incident to the finishing of the spline and body portions of a spline shaft, such as is used in transmission gearing, by grinding after the shaft has been hardened, and is the result of a series of experiments. The accuracy of the finished shaft was the primary consideration and three other groups of important considerations are stated, as well as four specific difficulties that were expected to appear upon departure from former practice. Illustrations are presented to show the tools used, and the method of using them is commented upon step by step. The shaft can be straightened to within 0.005 in. per ft. of being out of parallel with the true axis of the shaft, after the shaft has been hardened, and it is then re-centered true with the spline portion.

The development of intake-manifolds in the past has been confined mainly to modifications of constructional details. Believing that the increased use of automotive equipment will lead to a demand for fuel that will result in the higher cost and lower quality of the fuel, and being convinced that the sole requirement of satisfactory operation with kerosene and mixtures of the heavier oils with alcohol and benzol is the proper preparation of the fuel in the manifold, the authors have investigated the various methods of heat application in the endeavor to produce the minimum temperature necessary for a dry mixture. Finding that this minimum temperature varied with the method of application of the heat, an analysis was made of the available methods on a functional rather than a structural basis.

Dividing the ability of an automobile finish to remain new into the elements of proper quality of the materials, engineering of application systems, methods of application and care of the finish, the author states that the responsibility for them rests jointly upon the manufacturer of the varnishes and paints, the builder of the automobile and the owner of the finished product. Five basic materials that are necessary in automobile painting are specified and discussed. Engineering systems of application and the actual methods of application are treated in some detail, inclusive of drying, and of surfacing or rubbing. The care of the finish is important and the precautions necessary in this regard are outlined. The paper deals with the application and not the manufacture of the different varnishes and paints that are mentioned.

The process of continuous die-rolling and the products possible with this method of manufacture are described and illustrated. The improvements that have been made were the result of efforts to produce more complicated sections by this process, with greater accuracy, and these are discussed at some length. The physical characteristics of steel that must be considered are commented upon and forming that is effected in one pass is described, consideration being given the requirements of rolled forging blanks. The cost of operation is treated and the equipment used is discussed, showing how this process differs from other methods of making the same things, as to both the operations necessary and the character of the product.

Specifying the four general plans that have been followed by chassis builders in securing body equipment as being the building of bodies in their own shops; on contract by the body maker to plans and specifications of the chassis builder; by a local body maker to the order of the dealer or the owner; and the assembling from stock of standard sectional units recommended by the dealer or selected by the owner, the authors discuss each of these plans in detail. With regard to the plan of using standardized sectional bodies, the different sizes of chassis used for commercial purposes are separated into four specified groups and the production of a complete standard line including a number of styles of body for each chassis is commented upon and illustrated, inclusive of detailed considerations of the all-metal body.

The Chicago Service Meeting paper relates specifically to the type of garage equipment that is used to handle the motor vehicle in preparation for its repair. The devices illustrated and described are those designed to bring in disabled cars, and include wrecking cranes and supplementary axle trucks; portable cranes and jacks on casters for handling cars in a garage; presses, tire-changing equipment and wheel alignment devices; engine and axle stands; and miscellaneous minor apparatus. The different factors mentioned emphasize the great need of standardization. The thought is not to do away with a car's individuality, but to construct all parts so that cars may have efficient service to the highest degree through the agency of every serviceman.

After pointing out that although kerosene costs less than gasoline at the present time and is a cheaper fuel for the farmer to use, the author states that if the industry continues to construct tractors designed to use kerosene as fuel it will not be long before the cost of it is the same as that of gasoline. He argues that automotive engines should be designed to run on any liquid fuel and gives figures on the available supply of petroleum products and distillates in the world at the present time. The requirements laid down by the Government for gasoline are mentioned and it is stated that it is not possible for the oil industry to supply generally to the trade a gasoline meeting the recently adopted Government specifications which the author considers are very lenient.

The development of air-cooled engines for aircraft never made much progress until the war, when the British attempted to improve the performance of existing engines by a series of experiments leading eventually to the development of aluminum cylinders with steel liners and aluminum cylinder-heads with a steel cylinder screwed into the head. The advantages of these constructions and the disadvantages of other types are discussed. Results are reported of tests at McCook Field on a modern cylinder-design of this type showing good results, that lead to the belief that large air-cooled engines will be produced in the near future, equal in performance to water-cooled engines of the same power.

This paper is illuminative and affords an opportunity for better comprehension of the remarkable progress and accomplishment made in Europe along the lines of commercial aviation. Reviewing the present European routes now in regular or partial operation, the author stresses the essentialness of the attitude of the press in general being favorable if commercial aviation is to become wholly successful. The airship appears most practical for long-distance service, to the author, and he mentions the possibility of towns and cities growing up around “air ports.” The cost of airship travel is specified, although it is difficult to figure costs and necessary charges because so few data on the depreciation of equipment are available. Regarding successful operation, much depends upon the efficiency of the ground personnel and organization.

The author describes a process for drying coats of paint and varnish more rapidly than is possible with natural means, by adding heat and moisture simultaneously to the air surrounding the siccative coatings, through the employment of mechanical devices. The use of a fan and conditioning equipment to produce air circulation allows the process to be adapted readily to modern factory-schedules. Atmospheric conditions suitable for drying are discussed at some length as being a composite of sensible temperatures and relative degrees of humidity, and several humidifying devices are described and illustrated. Color control of paint by this means of drying is mentioned, examples being given, and numerous photographs showing installations of artificial drying equipment in use at various automobile plants are presented.

War service demanded that gasoline engines be absolutely reliable in minor as well as major details of construction; lightness of construction was second in importance. The war scope of the gasoline engine was so wide that engineers were forced toward the solution of unexpected and unrealized problems and a vast amount of valuable data resulted. This information includes recent determination of the quantitative nature of the factors governing thermodynamic performance in respect to mean effective pressure, compression ratio and the effect of volumetric efficiency; mechanical performance in regard to mechanical efficiency and internal friction; and engine balancing.

A tendency exists in most shops to assume that brazed joints cannot be successfully heat-treated. As a consequence, many fittings used in aircraft work and assembled by brazing smaller parts together are finished and installed without being heat-treated after the brazing operation. This practice causes parts to be used that not only do not develop the available strength of the material, but which are in some cases, under internal stress due to the heating in the brazing operation. Recent experiments made at the Naval Aircraft Factory show that the assumption mentioned is entirely erroneous. The author considers this matter with a view to specifying the use of steels and brazing spelters which will permit the subsequent or perhaps the simultaneous heat-treatment of the parts.

Iron ranks first of all the metals; copper, lead and zinc come fairly close together in tonnage; tin ranks next; and aluminum is fifth of the non-ferrous metals. The place of aluminum in the automotive industry is shown in a diagram and another brings out the production of copper and aluminum, both receiving comment. The metallography of aluminum alloys is discussed in some detail, as well as the phenomena of growth and aging, charts and photomicrographs being shown and commented upon. The effect of alloying on physical properties is treated in a similar manner in considerable detail and a comparison of aluminum with other metals follows. Forging alloys are described and some miscellaneous aluminum-alloy forged parts are pictured. The advantages of forging alloys are enumerated and many of their present uses specified; other contemplated uses for the newest alloy are for cast disc-wheels for passenger cars, differential carriers and cast rear-axle housings.

The adoption of the present system of feeding a number of cylinders in succession through a common intake manifold was based upon the idea that the fuel mixture would consist of air impregnated or carbureted with hydrocarbon vapor, but if the original designers of internal-combustion engines had supposed that the fuel would not be vaporized, existing instead as a more or less fine spray in suspension in the incoming air, it is doubtful that they would have had the courage to construct an engine with this type of fuel intake. That present fuel does not readily change to hydrocarbon vapor in the intake manifold is indicated by tables of vapor density of the different paraffin series of hydrocarbon compounds.