How do I check hole locations?

There are two main approaches: one way uses a surface plate, and the other uses a mill.

To check hole locations with a surface plate, you will also need a gage pin, gage block, and dial indicator. The goal of this approach is to measure the height of your hole relative to a gage block, which has a very precise (and known) height. To learn more about this approach, click here.

To find the center of a hole using a mill, you also use a dial indicator. The goal of this process is to locate the center of your hole relative to a reference feature on the part. For a video walkthrough of this process, click here.