Q: How to measure the inner diameter of a bearing with tapered bore?

The measurement of the bearing hole can use the inner diameter gauge to check the reference size on the outer micrometer and measure the roundness and cylindricity of the bearing hole. 

Burning out the bearing often reduces the diameter of the bearing hole at the opening and the roundness is out of tolerance, which is extremely detrimental to the normal operation of the bearing. 

If the positioning surface of the connecting rod bolt is loose, the connecting rod bearing cap will shift and the roundness of the bearing hole will be out of tolerance. 

The roundness error of the bearing hole should be controlled within the dimensional tolerance, and the cylindricity should be strictly controlled.