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Ceramic 36 grit for fast removal (or 24 grit if you want to be really aggressive)
piece will tend to stay cooler
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100 grit ceramic
piece will get hot
Finishing
3M Trizact Trizact
Will need belt cleaner
a bit priceypricy, but last a long time
from TruGrit, about $10 each
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Scotchbrite
But alternative brand (Red Label)
Also good for mill scale
Amazon - Red Label Abrasives 2 X 72 Inch Non Woven Surface Conditioning Sanding Belts for Knife Makers and Metal Fabricators - Coarse, Medium, and Fine Grits - 3 Pack Assortment. Set Set of three about $50 from Amazon
There is also an Extra Fine version
Norton Norax belts
pricey pricy but good
Have to search to find but Texas Knifemaker's Supply regularly carries https://www.texasknife.com
Come in up to at least 3000 grit, about $12 per belt.
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I have belts up to 2000 grit. After After that, for polishing steel (or aluminum), I use 3M Trizact disks in 35, 10, and 5 micron grits in a random orbital sander and final polish with 3M Fine Machine Polishing Compound on a buffing wheel. Gives Gives a mirror finish. (But, as I've been told many times, avoid a 'mirror' finish - it shows every flaw. (but done right it's exquisite))
With coarser grits, the heat tends to leave the piece with the ground off pieces (chips and sparks). Higher grits tend to leave the heat in the piece. So, for the same grinding speed and pressure, something being ground with a 24 grit belt will not get as hot as something being ground with a 220 grit belt. This becomes especially true at grits above about 600.
Sources
Maverick Abrasives Tru-Grit https://www.maverickabrasives.com/
Tru-Grit https://trugrit.com/
Texas Knifemakers Supply https://www.texasknife.com
Amazon www.amazon.com
Jantz https://knifemaking.com/
Pops Knife Supply https://popsknife.supplies/
Alpha Knife Supply https://www.alphaknifesupply.com/shop/
Maverick Abrasives https://www.maverickabrasives.com/
Combat Abrasives https://www.combatabrasives.com/
(Both of the above appear to be the same place doing business under 2 different names.
Combat site is easier to navigate. I've had recent reports that their belts are poor quality.)