What precision measuring tool is typically used for measuring crankpin and main bearing journals for out-of-round wear?

The micrometer caliper is the preferred tool for measuring crankpin and main bearing journals due to its ability to provide accurate measurements of small dimensions, typically within a range of micrometers. The design of a micrometer includes a calibrated screw mechanism that allows for precise measurements down to thousandths of an inch or hundredths of a millimeter. This level of precision is crucial when assessing out-of-round wear in journal surfaces, as even minor deviations can lead to significant mechanical issues.

In the context of crankshaft and bearing journal assessments, the micrometer is capable of measuring the diameters accurately along different axes, helping to identify any ovality or out-of-round conditions. This is essential for ensuring proper fit and function in engine components, where precision is paramount for performance and longevity.