Sandpaper grit size

[flatsguide]

It may not be what you think it is. We grew up, or at least I did with ANSI paper, but now a lot of stores are selling wet or dry with the letter P prefix. So when you think you are using 400 grit for example you may actually be sanding with 300 grit.
Cheers Richard







local 638

[D. Taylor Sapergia]

Interesting chart.

I go by the final finish, not what the paper says is the grit size.  I'm after anything from an even matt finish without file marks, to a mirror polish, depending upon the part and the function I expect from it.  A well used up piece of 320 grit will often be enough, for example, for the finish on a lock, if I'm going to rust brown/blue,  though often I take it to 1200 grit.

[kutter]

I kind'of go by the grit marking on the back. I do especially when the paper is new.
You get to know what you want as far as coarseness just by the feel.
Used paper,,it's all over the bench. I'm terrible for not tossing it.
But I keep using it over and over. Worn grit still has a purpose and the # on the back really means nothing after a while. It's what the surface looks like.

[Fly Navy]

I also go by the grit size on the back. However most of the time to get the finish I like I finish with maroon Scotch-Brite.