Mirror polished edges - Which steels are better (and worst) for taking them?

[Gibbo58]

I love CTS XHP, it sharpens and takes a mirror edge better than most steels I own.

[Chuck James]

I have a Native 5 Salt with LC200N that I use for a beater work knife. It has a 15 degree main bevel and a 22 degree micro bevel. I go all the way to a .5 micron strop and the edge seems to be holding very well.

[aaronkb]

Just got a Spyderco ultra fine today and put it to use on my s90v para 3 lw, which I’ve been having an embarrassingly hard time with... nearly mirrored it by accident. So I’ve gotta plug s90v for this, even though I haven’t enjoyed sharpening it nearly as much as everyone else apparently has.

[zuludelta]

I used to run polished edges on everything, but over time I observed it was extra effort for less edge holding. Now I sharpen PE knives on 200-500 grit diamond stones typically.

This mirrors (ha!) my experience as well, and it's especially apparent with PM steels with high vanadium carbide content (S30V, S35VN, S110V). I don't notice as much (if any) of an observable decrease in edge holding with mirror-polished edges in ingot stainless steels that rely mostly on chromium carbides, though (i.e., VG-10, 8Cr13MoV, AUS-8, ZDP-189, etc.). This is all just one amateur sharpener's anecdotal experience, though.

[Superflex]

Any steel can take a polish, but as a general rule of thumb, high carbide steels don't perform as well with a polished edge. The carbides act as micro serrations with high edge retention, so polishing smooths over the carbides, making them far less effective.

S30V will take a polish, but not as well as VG10, CTS XHP, BD1N, or other similar steels. Rex 45 works with a polish and so does M390/204P/20CV, but that's because of the lower vanadium content. In fact, M390 actually has more vanadium content than Rex 45, even if it's only by a very small amount. I usually finish my Rex 45 knives with a 1500 grit stone, then diamond spray/paste strops in 1, .5, and .25 microns. If I'm sharpening just for sharpness, the edge wont end up with a polish, but if I'm setting out to polish it, all it takes is a little more effort with the same grits.

Ive heard that anything over 4% vanadium requires diamond stones for sharpening, and should be sharpened to a lower grit finish, such as 400-600 grit. I'm not sure what that is based on, but it seems like the 4% cutoff works well (at least from what I've seen) as criteria for polished edges.

Thanks, Albatross! Really impressive.

I only use diamond stones and try to avoid steels with "an inclination to rust". I have two ATS-55 Spydies (a Dyad -the big one- and a Civilian) and though they are not in the EDC rotation and never leave the showcase (dry environment) I have to keep an eye always on them ...

I have a Delica 3 in ATS 55 and haven't seen a spot of rust on it in over 22 years of use. Mine goes in the dishwasher probably once a year when it gets oiled up from work and rides in my work pickup daily.
Not a safe queen for sure

52100 takes a mirror polish more easily than anything else I have.