Thread: Safe hardness for CPM154?

First post. Hi. I am a knifemaker that has started DE shaving two months ago, and I have acquired two straights in the past two weeks and been working at it since I got em. I can get through one WTG pass without blood but to me they are pulling a lot. Still my technique I know but they are not as sharp as they could be. Need to have em honed by a pro. Before I get serious AD I figured instead of dropping mad yak on a Dovo or getting a vintage, I can try to make my own (Who am I kidding? OF COURSE I am gonna buy more straights!).

I plan on using CPM154 since that is what I have laying around. Butch you had mentioned that you have finished some CPM154 @ 62, at what point does chip out become a concern? I do not necessarily want to temper this super hard if I do not really need to, I can only imagine the laps at the hone to get it going. I am about to order a 4" wheel and have at it just to see what comes up. I know depending on the grind there is more to it than that but I want this to be a simple project (I.E. I cannot afford more than one wheel right now). I just hope to get this done in a month cause the shop is getting closed up for a 365 to Korea.

As I'm sure you already know, the harder the steel the more brittle. 62 HRC is at the high end of tool steel hardness. Normal range is between 58 and 62. Since this will be your first razor I would suggest a double temper and try to keep the HRC above 54. It will be easier to hone, less prone to breaking while grinding, more stable but will need honing a bit little more frequently, at least touch ups. I really don't think the old Sheffield razors could be much harder than that. CPM will give you a nice fine grain structure which will help with edge retention.

Good luck!

You don't want to go higher than 62. And that is very difficult to hone if you are not experienced. There is also no real need to go that hard. Yes, the edge will last longer, but when it needs honing, it is going to take longer as well.

If you are starting out, I would definitely not go higher than 60. Many Sheffields I have honed and restored were only about 57 or 58 and they still have great edge retention.

i had my test razor and it was shavign wel but a bit harsh
sent it to tim for some Rc testing and was shocked at how hard it was (used my kitchen knife HT )

it was a strong 63.5 all but 64 hard
so back into the temper for a 3rd 2 hoours at a slightly higher temp

shaves great now and should be at a more user friiendly62rc (have not tested the new after 3rd temper hardness but feel i dont need to )

That sounds good. Eventually I am gonna have to learn how to hone and that would not be cool if I cannot hone something I have made cause it was so hard. I might just go with my recipe I use already, good for 60.5-61.

Thanks for the input.

that should work as you already have a HT that you have worked out