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Standard

CAMI / ANSI

North American coated-abrasive grading, ANSI B74.18

CAMI (ANSI B74.18) is the North American sandpaper grading, and it does not match FEPA past about 240. CAMI 400 is about 23 micron; FEPA P400 is about 35. CAMI specifies an average size, not a percentile range, so every grade here is a single median point, by the nature of the standard rather than a paywall.

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
100503020105
coarserfiner
inkmeasured or standardmaker figureour estimate
shapeknown distributionpoint, spread unknown
CAMI 36Standard-defined
median
535 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #30

CAMI 40Standard-defined
median
428 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #40

CAMI 50Standard-defined
median
351 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #50

CAMI 60Standard-defined
median
268 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #60

CAMI 80Standard-defined
median
192 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #80

CAMI 100Standard-defined
median
141 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #110

CAMI 120Standard-defined
median
116 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #130

CAMI 150Standard-defined
median
93 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #150

CAMI 180Standard-defined
median
78 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #180

CAMI 220Standard-defined
median
66 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #210

CAMI 240Standard-defined
median
53.5 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #250

CAMI 280Standard-defined
median
44 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #300

CAMI 320Standard-defined
median
36 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #350

CAMI 360Standard-defined
median
28.8 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #420

CAMI 400Standard-defined
median
23.6 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #510

CAMI 500Standard-defined
median
19.7 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #610

CAMI 600Standard-defined
median
16 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #720

CAMI 800Standard-defined
median
12.2 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #940

CAMI 1000Standard-defined
median
9.2 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #1250

CAMI 1200Standard-defined
median
6.5 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #2050

CAMI 1500Standard-defined
median
5.5 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #2350

CAMI 2000Standard-defined
median
5 µm

Coarse grade, sieve-graded.

spread sieve-graded · reference scale about #2500