Fineness Of Grind Gauge Fineness of grind gauge is used to indicate the fineness of grind or the presence of coarse partials in a depression. It is a flat corrosion resistant stainless steel block. There are two flat-bottomed taper grooves varying uniform in depth from a maximum at one end of the block to zero near the other end. Groove depth is graduated on the block according to one or more scales used for measuring partial size. The degree of depression is indicated in microns or Hegman scale. Models: - *0-100 microns = 8-0Hegman. *0-50 microns =8-4Hegman. *0-25 microns =8-6Hegman.