Originally Posted by
Euclid440
Iron Oxide and Cerium Oxide both work well for a finer edge, Iron Oxide has been used for many years.
I have use both, for years, good Iron Oxide can be purchased inexpensively from Kremer Pigments. I don’t recall where I bought my Cerium Oxide years ago.
The last few years I have use CBN, in place of both, as you can get it in much finer grits that cut much faster.
A .125 or .25um CBN edge is very comfortable and can be stropped on daily, .125um is about 120K grit equivalent. You can go, as small as .10um/ 160k grit, which for me is too keen.
Yes, it is not just about grit size, Paste, polish and cut microscopically where a hone cuts much more aggressively.
If you use a SG20k/.50um stone to finish, you can still polish it further for comfort, with .50um Chrome Oxide or .50um CBN and get 3 different finishes.
If you do too many laps on the SG20 you can easily thin an edge so much, that the edge will fail and chip. The SG20 is a very aggressive stone.
So as above, even though all three are the same grit size, they will deliver much different finished edges. It’s not just grit size that makes the difference.