I made a set out of annealed O1, and left them soft so I could sharpen them with a file. They hold an edge fine, I suspect 4142 would be about the same. I cut the teeth on a metal shaper, which worked great but if I were to do it again I think I'd vary the pitch a bit. I think it would eliminate the slight chatter that I get. I'd guess if you are going to create the teeth by hand filing there will be enough pitch variability to take care of this issue.