Thread: CPM M4 steel for razors

Originally Posted by onimaru55

Don't you run the risk of damaging a finished razor by doing that ?

+1 I wonder also.

If you tested on the hollow, very likely to break. If tested in an area readily supported from underneath and thick enough cross section then no problem. The tang would be best bet, near to the grind. If there is enough meat at the spine that would also be good.

Jeff

Originally Posted by onimaru55

Don't you run the risk of damaging a finished razor by doing that ?

Not really. If the tang was hardened with the blade, it will have the same hardness.

Agreed. I had thought to get them tested close to the pivot and assume the same hardness throughout. Providing of course the tester concurs- preferably a blade-smith.

You could test the CPM M4 and the Carbon Chromium Alloy on the spine with no problem both have close to 3/16 x 3/16 of steel there, plus I don't think either would break there.

The only time I watched a test like this being done the issue was holding the blade evenly and securely. We used a heat treated blank before the final grind and that was fine but I wouldn't have used one after it was finished. Granted it was an older machine and maybe the new ones are more forgiving.

Tim

Originally Posted by bishpick1

You could test the CPM M4 and the Carbon Chromium Alloy on the spine with no problem both have close to 3/16 x 3/16 of steel there, plus I don't think either would break there.

No, but the tester needs a stable surface to push into.
It could be problematic to set up the spine in a way that would be stable and not prone to sliding.

Question:

What is the difference between heat treating now, and heat treating say a Wade & Butcher Chopper ????


I ask because there is a difference between the hardness of the spine and tang on them compared to the blade..

The short answer: we don't know.
I've never seen documentation about the HT specifics of Wade and Butcher.
To be honest, I doubt it is public. HT information caused the rise and fall of empires.

Do you know why the English fleet dominated the oceans for a long while? Soft cannon balls. The English craftsmen put the freshly cast cannon balls in ash pits, letting them cool off over weeks. The French and Spanish otoh quenched their cannon balls. As a result, when a French cannon ball hit a solid object like the hull of a ship, it shattered, doing only minimal damage.
An English cannon ball otoh would just deform, lose none of its energy by shattering, and then punch through, like an oversized softnose bullet.

Other HT secrets used to be the manufacture of wootz steel, and the HT of traditionally forged katana.
This makes sense. Competitors are all using similar materials to work with, and HT can make a huge difference. As such, HT was probably not shared with outsiders.

To get back to your question (and this is just guessing): if they were using a fairly plain carbon steel, it is to be expected that the spine and tang are softer. They cool slower, and the since the simple steel is not through hardening, you end up with a hard edge and a soft(er) spine.

It just makes no sense to me to use a super alloy steel like this in a Razor. But I will keep an open mind as i'm yet to test this steel myself. I would be interested to see a ht'd break sample close up to see the grain structure compared to any of the purpose built fine grained cutlery steels, ie white paper steel, 01 or AEB-l.