Find the true center of threaded holes to precisely align and measure parts. Once you thread these gauges into a hole, their cylinder sticks out as a reliable reference point. They’re often used with a coordinate measuring machine (CMM) to pinpoint the coordinates of the cylinder’s exact center. You can then use those coordinates to measure distances between points or reference them for error-free assembly. Even without a CMM, you can use these gauges with a micrometer to measure accurate center-to-center distances.