Which tool can be used to determine piston pin out of round wear?

Which tool can be used to determine piston pin out of round wear?

• A. Dial gauge
• B. Depth gauge
• C. Micrometer caliper
• D. Micrometer

Answer: (C)

Measuring roundness of a cylindrical part requires precise external diameter readings at multiple orientations. A micrometer caliper is the tool designed for high-precision diameter measurement. By taking measurements at different angles around the piston pin—rotating it and checking the diameter at each position—you can detect any variation from a true circle, which indicates out-of-round wear. The dial gauge can sense runout but doesn’t directly provide a diameter value, and depth gauges measure depth rather than diameter. A micrometer by itself can measure outside diameter, but the micrometer caliper is the standard instrument for quickly and accurately assessing roundness of a cylindrical pin.

Measuring roundness of a cylindrical part requires precise external diameter readings at multiple orientations. A micrometer caliper is the tool designed for high-precision diameter measurement. By taking measurements at different angles around the piston pin—rotating it and checking the diameter at each position—you can detect any variation from a true circle, which indicates out-of-round wear. The dial gauge can sense runout but doesn’t directly provide a diameter value, and depth gauges measure depth rather than diameter. A micrometer by itself can measure outside diameter, but the micrometer caliper is the standard instrument for quickly and accurately assessing roundness of a cylindrical pin.