How can the dimensional inspection of a bearing in a rocker arm be accomplished?

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

Answer: (D)

Measuring an internal bore like the bearing inside a rocker arm requires a tool that can reach inside and then be read with a precise external instrument. A telescoping gauge is used to span and gauge the inside width: you insert it, extend it until it touches the bore walls, lock it, remove it, and then measure that transferred dimension with a micrometer. The micrometer provides a precise internal diameter reading once the gauge is removed. This method is ideal here because the bore is small and inaccessible to direct external measurement, and you can’t capture an internal size with a standard micrometer alone.

Depth gauges measure how deep something is, not its width; dial gauges measure displacement or runout rather than a true internal diameter; thickness gauges measure material thickness, not bore size; and a push fit arbor isn’t a tool for taking internal bore measurements.