Feeler gauges are used:
– To check the gap between the mating parts
– To check and set the spark plug gaps
– To set the clearance between the fixture (setting block) and the cutter/tool for machining the jobs
– To check and measure the bearing clearance, and for many other purposes where a specified clearance must be maintained.

The process of enlarging and finishing previously drilled holes to accurate size using a multi-point cutting tool is called as Reaming. The Tool used for this process is called Reamer.