on a razor best way is to buff it
take it to 600 greaseless and that gives you perfect satin if done right.
I am not a authority on the subjet but I would stay away from a buffer with a straight razor. it is way too easy to overheat the thin blade and totally ruin it. I have also made quite abit of money "fixing " razors that were buffed and the edge rounded so badly that they had to be taken to a 220 grit stone to reestablish proper edge geometry.
Yes this is a problem, this can happen when people have no experience, the buffing wheel is too big for the razor (6" used for 5/8 razor for example), or people want to remove too much material and hit the edge.I have also made quite abit of money "fixing " razors that were buffed and the edge rounded so badly that they had to be taken to a 220 grit stone to reestablish proper edge geometry.
I just remembered a way to get even finish by hand, an eraser will deform to accomodate the shape of the blade and will give very nice even finish.
It is pretty easy - I start with a 220 grit from my belt grinder, and from them I can hand rub with 320 grit sandpaper using mineral oil and a hard backing like a micarta block, and repeating the process to the desired grit of sandpaper. As a final step you can use scotchbrite and it will make the blade less bright. Of course, be prepared to spend some elbow grease in the process, too! As with everything in life, it will become easier and simpler as you get more pratice.
One thing to add that I had wrong when I first started knife making, you dont need to go all in one direction until the end. Now I scrub the daylights out of the blade going back and forth and also switch directions with each grit until over 600.