This set consists of 30 comparison specimens covering six commonly used machining methods (6 horizontally milled, 6 turned, 6 plain-ground, 3 lapped, 3 external ground ).
A label gives the Ra values off each specimen in both metric and imperial units.
The measurement of surface roughness is not as straightforward as most other engineering measurements, such as length or angle or hardness and in order to get good accuracy, expensive instruments are needed.
These are often unsuitable for workshop use where roughness of machined surfaces can usually be assessed conveniently and with sufficient reliability using visual and tactile (fingernail) comparison with a standard set of surfaces machined in the same way.
These problems are solved by our surface roughness specimens set which is simple to use, inexpensive and hence widely used in many different applications.