A radius gauge, also known as a fillet gauge,[1] is a tool used to measure the radius of an object.[2]
Radius gauges require a bright light behind the object to be measured. The gauge is placed against the edge to be checked and any light leakage between the blade and edge indicates a mismatch that requires correction.[3]
A good set of gauges will offer both convex and concave sections, and allow for their application in awkward locations.
Every leaf has a different radius, for example with radius intervals of 0.25 mm or 0.5 mm.[4] The material of the leaves is stainless steel. Each gauge is one of two types; either internal or external, which are used to check the radius of inner and outer surfaces, respectively.