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A coarser paper has a low number because fewer strands cross each inch. The figure is taken from National Institute of Standards and Technology, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Mondo Knows Facts

Sandpaper grit numbers count mesh openings

A coarser paper has a low number because fewer strands cross each inch Coated abrasives are graded by sieve, and in the older CAMI system the number is roughly the mesh count per linear inch, so 80 grit passes through a finer screen than 40. European FEPA papers use a P prefix and grade by measured particle size in microns instead. Either way the number describes the abrasive grain, not the paper. It sits in Mondo's everyday life collection, one of 200 facts that each trace back to the reference below.

Where this comes from

National Institute of Standards and Technology

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Tags: tools, abrasives, workshops

Sandpaper grit numbers count mesh openings: the short answers

Where does this come from, and can I check it?: A coarser paper has a low number because fewer strands cross each inch. The figure is taken from National Institute of Standards and Technology, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a everyday life fact?: Yes. It sits on the Everyday Life shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.