What is a feeler gauge?

A feeler gauge is a tool used to measure the gap between two parallel surfaces. It typically consists of a set of thin metal blades or wires that are of varying thicknesses. These blades are inserted between the two surfaces, and the user can determine the gap size by selecting the blade that fits snugly without forcing it.

Feeler gauges are commonly used in automotive and engineering applications to check and adjust the clearance between moving parts, such as spark plugs, valves, and piston rings. They are also used in metalworking and woodworking to ensure precise measurements and alignments.

Feeler gauges are available in metric and imperial sizes, and they can be made from materials like stainless steel, brass, or plastic. They are compact and easy to use, making them a versatile tool for machinists, mechanics, and hobbyists alike.