Maintaining many different gauges
Plug gauges in storage
A ring-shaped component is checked using a plug gauge.
The word "gauge" can mean a standard or a yardstick. Numerous gauges can be found at Mr. Sasaki's workshop.
The photograph shows a tool known as a plug gauge, which is used for checking whether the diameter of a ring-shaped component meets the standard size requirements. A plug gauge consists of a central handle for holding the instrument and gauges at both ends. The gauge at each end differs slightly from the other in diameter, with one end having a diameter equal to the maximum internal diameter for the component, and the other end having a diameter equal to the component's minimum internal diameter. In other words, if the internal diameter of the component is correct, it will be possible to insert the minimum-diameter end of the gauge into it, but impossible to insert the maximum-diameter end.
Nikon currently procures gauges externally, and it is Mr. Sasaki's job to inspect these gauges and to distribute them to the production sites. Depending on how they are used, gauges can change shape or wear out, which makes them unsuitable for use. Mr. Sasaki periodically measures gauges, using a measuring instrument, to check whether they are still up to standard.