Which combination of instruments is used to perform the dimensional inspection of a rocker-arm bearing?

Which combination of instruments is used to perform the dimensional inspection of a rocker-arm bearing?

• A. Telescopic gauge and micrometer
• B. Depth gauge and micrometer
• C. Thickness gauge and push fit arbor
• D. Dial gauge and micrometer

Answer: (A)

Measuring an internal bore requires a tool that can access the inside of the hole and then translate that internal size into a readable value on a standard instrument. A telescoping gauge fits inside the bore and, when expanded to touch the bore walls, locks in place. Removing it and measuring its extended length with a micrometer gives an accurate internal diameter of the rocker-arm bearing bore. This combination is the established way to capture inside dimensions and then read them with a precise external-reading instrument, ensuring the bore is within tolerance for proper bearing fit and function. Other tools shown wouldn’t provide the same reliable internal diameter measurement. A depth gauge with a micrometer isn’t suited for capturing a circle’s internal diameter. A thickness gauge with a push-fit arbor relates more to material thickness and fitting parts than to measuring an internal bore. A dial gauge plus a micrometer doesn’t directly yield the bore’s true inside dimension without a transfer gauge like the telescoping gauge.

Measuring an internal bore requires a tool that can access the inside of the hole and then translate that internal size into a readable value on a standard instrument. A telescoping gauge fits inside the bore and, when expanded to touch the bore walls, locks in place. Removing it and measuring its extended length with a micrometer gives an accurate internal diameter of the rocker-arm bearing bore. This combination is the established way to capture inside dimensions and then read them with a precise external-reading instrument, ensuring the bore is within tolerance for proper bearing fit and function.

Other tools shown wouldn’t provide the same reliable internal diameter measurement. A depth gauge with a micrometer isn’t suited for capturing a circle’s internal diameter. A thickness gauge with a push-fit arbor relates more to material thickness and fitting parts than to measuring an internal bore. A dial gauge plus a micrometer doesn’t directly yield the bore’s true inside dimension without a transfer gauge like the telescoping gauge.