Note: The grit designation is prefixed with a "D" to denote diamond and a "B" to denote CBN

 

 

Narrow Range Grades   

 

FEPA Grit Designation approx. mean size µm	U.S. Standard ASTME 11	BRITISH BS 1987
1181	16/18	14/16
1001	18/20	16/18
851	20/25	18/22
711	25/30	22/25
601	30/35	25/30
501	35/40	30/36
426	40/45	36/44
356	45/50	44/52
301	50/60	52/60
251	60/70	60/72
213	70/80	72/85
181	80/100	85/100
151	100/120	100/120
126	120/140	120/150
107	140/170	150/170
91	170/200	170/200
76	200/230	200/240
64	230/270	240/300
54	270/325	300/350
46	325/400	350/400

FEPA Grit Designation approx. mean size µm	U.S Standard ASTME 11	BRITISH BS 1987
1182	16/20	14/18
852	20/30	18/25
602	30/40	25/36
502	35/45	30/44
427	40/50	36/52
252	60/80	60/85