I thank you for that suggestion, and it is a useful resource, but (unless I am misinterpreting something) it does not go nearly fine enough for my needs.
Interestingly, I have been building an Excel spreadsheet with just that information. Most sources don't go smaller than 5 microns, so I took an existing table and added the smaller data from various sources. It may be useful to others. Note that there is some variation in different sources between what "CAMI" vs. "FEPA" vs. "Microns" and "Japanese" actually measures to.
Since rec.woodworking doesn't want binary attachments, I've attached a "CSV" file (means comma separated value, I think) that can be loaded into just about any spreadsheet program out there.
Since I don't know that rec.woodworking even wants that, I've also pasted the CSV information below. You could copy that and paste it into Notepad (or other plain text editor) and save it to a file, then load that file into your spreadsheet program.
Good luck
,CAMI Grit designation,ISO/FEPA Grit designation,Japanese,Average particle diameter (µm),Examples Extra Coarse (Very fast removal of material),,P12,,1815, ,,P16,,1324, ,,P20,,1000, ,,P24,,764, ,24,,,708, ,,P30,,642, ,30,,,632, ,36,,,530, ,,P36,,538, Coarse (Rapid removal of material),40,P40,,425, ,50,,,348, ,,P50,,336, Medium (sanding bare wood in preparation for finishing),60,,,265, ,,P60,,269, ,,P80,,201, ,80,,,190, Fine (sanding bare wood in preparation for finishing),,P100,,162, ,100,,,140,Coarse Crystolon ,,P120,,125, ,120,,,115, Very Fine (final sanding of bare wood),,P150,,100, ,150,,,92,Medium Crystolon ,180,P180,,82, ,220,P220,,68, Very Fine (sanding finishes between coats),,P240,,58.5, ,240,,,53,Fine Crystolon ,,P280,,52.2, ,,P320,,46.2, ,,P360,,40.5,40 micron SiC paper Extra fine,320,,,36, ,,P400,,35,Extra fine scotch brite pad ,,P500,600,30.2, ,360,,,28,Washita oil stone ,,P600,,25.8, Super fine (final sanding of finishes),400,,,23, ,,P800,,21.8, ,500,,,20,Soft Arkansas stone ,,P1000,,18.3, ,600,,,16, ,,P1200,,15.3,"15 Micron belt, 15 micron SiC paper" Ultra fine (final sanding of finishes),800,P1500,2000,12.6,"Hard white Arkansas, extra fine diamond, and medium ceramic" ,1000,P2000,4000,10.3, ,,P2500,,8.4,"Hard black Arkansas, 9 micron belt" ,1200+,P4000,,5,5 micron SiC paper ,1500,P6000,6000,3,"Extra fine white Ceramic, green chrome rouge, 3 Micron belt." ,,,8000,2 or 3,Japanese Water stone ,2000,,15000,0.9,Japanese Water stone ,12000,,30000,0.5,"Chromium oxide polishing compound, 0.5 micron Chromium oxide paper, Shapton 30000 stone, diamond paste "
I once spent a fair amount of effort to resolve this exact issue. I compiled a spreadsheet, based on several sources, regarding the relative grit-size of the various grading systems. I'll post hte spreadhseets over on teh binaries group, with a bit of detail.
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