It seems easy but is difficult... "PCD/PCR testing tools"

[Concern] I want to measure the PCD and PCR of a hole.

<Measuring the PCD (diameter) and PCR (radius) of holes> In machining processes such as machining centers, forging, and pressing, multiple holes may be processed. When the holes are arranged in concentric circles, they are often processed based on their diameter (PCD) or radius (PCR). After such processing, there may be a need to confirm that the holes have been accurately machined to the specified positions. Measuring PCD or PCR with general measuring tools is quite difficult. Measuring with a non-contact three-dimensional measuring machine is relatively easy, but it is not practical to set it up right next to the manufacturing line for measurement. Additionally, while a non-contact three-dimensional measuring machine can measure the opening of the hole, it is impossible to confirm whether the hole is straight or whether the diameter decreases when the hole becomes deeper. <Easily Measuring> The best way to easily measure multiple holes arranged in concentric circles is to use a gauge (measuring tool, inspection tool). Depending on how it is made, it is possible to check the PCD along with the hole diameter, depth, and the relationship between the angles of the holes all at once. By using a gauge, anyone can easily perform measurements, and the inspection results will be stable.

Distance measuring device