Which precision measuring instrument is used when performing a connecting rod twist inspection?

Which precision measuring instrument is used when performing a connecting rod twist inspection?

• A. micrometer
• B. dial indicator
• C. vernier caliper
• D. thickness gauge

Answer: (D)

Twist inspection of a connecting rod looks for torsional distortion that changes the cross‑sectional thickness on opposite sides of the rod. By measuring how thick the rod is from one face to the opposite face at a specified location, you can detect even small twists that would put the rod out of spec. A thickness gauge is ideal here because it directly reads the small differences in material thickness between the two faces, giving a precise value that can be compared to the allowable tolerance. You’d typically support the rod on a flat surface and take readings on opposite sides, then compare the difference to the spec. A micrometer measures thickness at a single point and isn’t suited for comparing opposite faces to detect twist. A dial indicator measures deflection or runout rather than a static thickness difference. A vernier caliper has limited precision for small thickness variations. The thickness gauge, with its calibrated steps, provides the appropriate precision and approach for identifying twist.

Twist inspection of a connecting rod looks for torsional distortion that changes the cross‑sectional thickness on opposite sides of the rod. By measuring how thick the rod is from one face to the opposite face at a specified location, you can detect even small twists that would put the rod out of spec. A thickness gauge is ideal here because it directly reads the small differences in material thickness between the two faces, giving a precise value that can be compared to the allowable tolerance. You’d typically support the rod on a flat surface and take readings on opposite sides, then compare the difference to the spec.

A micrometer measures thickness at a single point and isn’t suited for comparing opposite faces to detect twist. A dial indicator measures deflection or runout rather than a static thickness difference. A vernier caliper has limited precision for small thickness variations. The thickness gauge, with its calibrated steps, provides the appropriate precision and approach for identifying twist.