Imagine your task for this week is to develop a hand tool gaging solution for a large rotor with an ID of nearly 400mm. Given the size and the large diameter, it is unlikely the part can be brought to a gage or even a CMM for an in-process check. Instead, the diameter will need to be measured at the point of manufacture. One could typically use an adjustable bore gage or an inside rod micrometer to check the large diameter. However, this part has a hub in the center of the diameter to be checked and presents an obstacle.
As with any diameter measurement, there are several possible solutions, usually tolerance based. Once a diameter approaches this size, the tolerances are relatively loose, providing several potential options. There are even solutions for a large precision diameter. This article will examine the scope of gages that have the potential to solve this requirement.