A Feeler gauge is used to measure the clearance between two parallel flat faces for example piston and cylinder. As the name suggests, feeler gauge called as to measure neither tide nor freely.

Feeler gauges are used for measurement of clearances. It is a tool that measures air or narrow gap widths between two surfaces in engines and machinery.

The working of feeler gauge is easy. The blades are kept on the vacant gap that needs to be measured, initially one blade of standard thickness is kept, then if there are extra gaps other blades are adjusted and joined together and used.

Ensure that the blades can be easily pushed to and fro and are not tight nor free to move. In order to have a problem-free measurement, the blades should be free of dirt and grease.