Section 3. Research and Development of Basic Technology
Item 4. Research and Development of Machining Methods and Machine Tools
In 1934, the production of transmission prototypes was started and gear fabrication commenced. However, the gear shape was unclear, and it was not known which cutting tools should be used for the gear finishing machine. Kiichiro Toyoda consulted his friend, Professor Shiro Nukiyama of Tohoku Imperial University, who introduced him to an expert on gears at the university, Dr. Masao Naruse. Also, arrangements were made for Jiro Iwaoka1 and Tatsuji Wakamatsu2 to transfer to the university for study purposes in November 1934.
The two students attended lectures by Dr. Naruse on gear theory and then brought along Chevrolet transmission gears for analysis. Using machinery plant microscopes equipped with measuring apparatus, they measured the gear tooth form precisely in units of 1/100 millimeter. Based on that data, they drew gear tooth curves enlarged 10 times3 and, using the theoretical formulae established by Dr. Naruse, they determined the gear geometry and ordered a cutter. This was the first time Dr. Naruse's theories had been put to practical use.4
In the first half of 1934, imported machine tools were set up in the automobile prototype plant and used as reference materials by Toyoda Automatic Loom Works and, in 1935, the in-house production of machine tools commenced. Subsequently, to allow for the full-scale production of machine tools and jigs for automobile mass production, in June 1937 an Automotive Department Machining Plant was established within Toyoda Automatic Loom Works.
At the time, the majority of Japanese produced machine tools were of the full-universal type suitable for various sorts of processes and used in many kinds of small-lot production. For that reason, they were even equipped to carry out functions in specialized tasks not needed for automotive mass production. As a result, imported machines were used as reference materials in designing and producing machine tools and specialized machines in the Machining Plant that were limited to the required functions in automotive mass production. For example, the type A lathe produced in the Machining Plant, with its simple construction and reliable and light maneuverability, was highly-regarded. Similarly, the distinctive features of the type C lathe were its simplification of the mechanisms surplus to lathes used for the production, and a design emphasizing maneuverability.
These lathes were provided to Toyota Motor Co., Ltd.'s Machining Plant and its successor, Toyota Machine Works, Ltd., and the type A lathe was also the first in a series comprised of types A, B, C, D (DD), E, F and G lathes. Among these, the type E lathe was a production lathe designed and manufactured in the Toyota Motor Co., Ltd. Machining Plant, with the simplest type of construction and streamlined mechanisms emphasizing maneuverability. Since it was rated highly for its quiet turning in the cutting finish and its machining accuracy and, and its cost was comparatively low, Toyoda Machine Works increased its production of these lathes to 10 per month.5
The Toyota Motor Co., Ltd. Koromo Plant Machining Plant was completed in November 1938, and the design and manufacturing of machine tools from within Toyoda Automatic Loom Works was transferred to that plant. Subsequently, a variety of machine tools, including the ordinary lathes referred to above as well as multi-spindle drilling machines, automatic multicut lathes, fine-boring machines, and machine tools specifically for automotive manufacturing, were produced at the plant.
On May 1, 1941, based on the Machines Manufacturing Industries Law, the Machining Plant was spun off from Toyota Motor Co., Ltd., and Toyoda Machine Works, Ltd. was established. After its establishment, in accordance with the national policy, production of machine tools for automobiles decreased, and emphasis was placed on machine tools for aircraft engine production.6