Generally thread depths are designed to be measured from the center line of the first full thread in the bottom of the threaded hole. This means that the gage must also be manufactured to measure from the same location. The depth notch on the go thread plug gage is usually ground 90 degrees to the axis of the gage.Feb 1, 2013
What is a thread depth gauge?
A thread depth gage instrument allows you to measure depth of the thread and its quality with GO and NOGO gages. It is a simple, convenient, time saving and inexpensive way of measuring two times the major thread diameter, as compared to the conventional methods.