No particle size in microns is published for this line. The values are our estimates from secondary sources, so the marks are faded and the spread is unknown.
Each grade below shows its size in microns, its spread (the published distribution, where a maker or standard gives one; most makers publish none), and where that size lands on the reference scale, a shared yardstick for reading grit numbers across makers.
Particle sizemicrons, log
1005030201053
coarserfiner
inkmeasured or standardmaker figureour estimate
shapeknown distributionpoint, spread unknown
120 gritOur estimate
Boride
109 µm
C-estimated: Boride states grit 120, no micron; 109 micron is the FEPA-F d50 (sieve-graded).