Which tool is typically used to measure surface roughness?

The tool that is typically used to measure surface roughness is a roughness tester. This specialized instrument is designed to provide precise measurements of the texture of a surface by evaluating the peaks and valleys in its finish. It can quantify various surface parameters, such as arithmetic average roughness (Ra) and root mean square roughness (Rq), which are important for quality control in manufacturing processes.

Roughness testers can be either contact types, where a stylus moves across the surface, or non-contact types, which use laser or optical methods to assess the surface profile. The capability to accurately measure surface characteristics makes the roughness tester essential in scenarios where surface finish directly affects functionality, such as in bearings, sealing surfaces, or aesthetic qualities of a product.

Other tools listed, such as calipers and micrometers, are primarily intended for measuring dimensions such as length or thickness rather than surface texture. While they can provide some information related to surface characteristics, they lack the specificity and accuracy required to effectively measure surface roughness. No gauge does not serve any measurement purpose in this context.