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Request for repair of a grinder delivered 50 years ago

The grinders used in the final machining process require the most accurate parts machining and assembly. Involved in the assembly and repair of spindle units, the hearts of grinders, for more than 30 years and selected as a Contemporary Master Craftsman, the title of a top master, Yuji Kawamura has one particular memory he will never forget.
A request for repair of a special specifications GPB cylindrical grinder delivered to a customer more than 50 years ago had been brought to Mr. Kawamura one day. That machine is now displayed as Mechanical Engineering Heritage in the Okuma Memorial Gallery. When he disassembled and inspected it, he found that the unit had suffered serious damage, including seizing, due to poor maintenance, and the majority of its parts needed to be replaced. However, Mr. Kawamura concluded that it could not be repaired because there were no parts in stock or drawings for the machine and because it would take more than a year to complete the repairs even if he undertook them.
But the customer did not give up, saying, "This machine is used for critical machining that cannot be handled by other machines. I would like you to fix it no matter how long it takes or how much it costs." Ultimately, Mr. Kawamura manufactured all the parts for it from scratch, and with the full cooperation of the manufacturing department, he revived the machine in a year and a half, pouring all his knowledge, experience, and skills into it. The customer was extremely impressed, and Mr. Kawamura himself was filled with joy and a sense of accomplishment.

I want to do something about it.
Let's try it! Don't give up!

In 2007, Okuma's grinders changed dramatically. The conventional belt drive system was converted into an integral motor/spindle drive system with built-in motor in the grinding wheel spindle in order to improve the rotational speed and accuracy of the grinding wheel spindle.
As a result, the bearing support parts, which were integrated with the grinding wheel spindle in the previous structure, were divided, and this required work to align the centers of each inner surface, so the difficulty of assembling the unit increased.
During the prototyping stage, the assembly department remarked that the structure would be complicated and that they were worried about being able to prevent misalignment. When Mr. Kawamura heard this, it sparked a feeling of wanting to do something about it, and he called on his colleagues to give it a try first and worked hard to find a solution. After much trial and error, he quantified the dimensional accuracy, which relied on the senses of expert engineers, and documented the alignment and adjustment work in a manual. In that process, he developed a feeler gauge, an instrument inserted into the inner surfaces of bearings and used as a reference for dimensions. Through dimensional control, he established a system to ensure that special skills were passed on to others, leading to stable manufacturing.
In this way, conversion to an integral motor/spindle for grinding wheel spindles got on the right track, and the value of Okuma grinders increased further, with rotational accuracy increasing from 0.02 to 0.01 μm and the maximum practical speed increasing from 2,000 to 6,000 rpm.
Based on this experience, Mr. Kawamura says, "The most important thing is not to give up easily." This is the craftsmanship that continues to live on in Okuma.