LSTM-17 test method.
This is quoted on talc and kaolin data sheets, for example.
Here is a good description of the method from gardco.com:
In its simplest conception, a Fineness of Grind Gage may be considered essentially a continuous variable screen. It can be readily seen that if a material such as fine silica were distributed uniformly in a single particle thickness in the gage path, these particles would protrude above the sides of the path starting at whatever point that their physical size exceeded the depth of the path.
If a straight edge scraper was brought to bear on the sides of the path in conjunction with the deepest part, and then moved slowly down the path to the shallow end, it would contact the protruding particles and on continued movement, screen or push these particles from the path.
Guardco Hegman Fineness Page
|Tests||Sieve Analysis Dry|
|Tests||Sieve Analysis Wet|
|Tests||Sieve Analysis 35-325 Wet|
|Tests||Wet Sieve Residue|
Tests conducted to determine particle populations, sizes, shapes, densities, surface areas, etc.