Tip #5
Everything you need to know about Sanding! (continued)
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How are sandpapers graded?

There are three ways of grading abrasive papers: by name, such as coarse, medium fine, etc. - by grit numbers, such as 60, 80, 100, etc. - and by “aughts”, such as 1/0, 4/0, 7/0, etc. The latter of these is not a common.

Although the names (coarse, etc.) are the easiest to understand, the ways manufacturers use these terms vary so much that they can be confusing. One manufacturer may call a 320-grit paper “very fine” while another may call it “extra fine”.

Usually, papers will carry both a name and a grit number. Grit numbers range from 12 (extra-coarse) to 600 (extra-fine), while “aught” designations range from 4-1/2 (extra coarse) to 10/0 (extra-fine).

Grit numbers and “aught” designations are assigned by sifting abrasive particles through progressively smaller sieves, with the number of openings per linear inch determining the grit number. For example, 80-grit abrasive particles are selected with sieves having 80 openings per linear inch.

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