Sep 28, 2021 #1 enginesrus Mechanical Joined Aug 30, 2003 Messages 1,026 Location US What abrasive grit will give a .23 micron finish on hard steel?
Sep 28, 2021 1 #2 3DDave Aerospace Joined May 23, 2013 Messages 11,459 Location US This chart says 400, I think: https://www.ljstar.com/resources/surface-finish-charts/ Upvote 0 Downvote