Thread: CPM M4 steel for razors

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.

Originally Posted by raisedbybrocks

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.

M4 may not possess as fine a grain as the above but it is quite fine. There are several aspects I am testing here, not easily separated:

1) Edge sharpness (fine grain plus brittleness/ductility)
2) Edge deformation (hardness)
3) Wear resistance (carbide formation/distribution)
4) Sharpenability
5) Shave comfort and smoothness

AEB-L is a purpose made cutlery (razor) steel but it is a strip steel like 15n20/L6, typically under 0.20" thick. Sandvik makes the same great product but again, quite thin. I like it heavy.

When I started this thread specifically for the razor user I was unaware of the number of members who have tried different products and come to their own conclusions about the trade-offs above. Most have found that a few extra shaves are not worth the added effort of sharpening when it comes to extreme hardness or wear resistance. I just happened to have a flat of M4 and wondered why I could not find any feedback on it from razor users. It just made sense to me to give a "super steel" a try and compare it to a good "cutlery" steel. If only I could get that edge really polished.......

Along with the advances in steels we also have advances in stones like diamond, sapphire and ceramic; making honing potentially much less of a chore. In fact, I think I am going to pull the trigger on that Spyderco Ultra-fine (10K)

If you could not find a readily available vintage blade in the shape and weight you preferred and found a bladesmith who could give you a choice, what steel would you choose and why? Have you tried it? I certainly appreciate the experiences of others. I just thought to gain my own experience and opinion and share it. It's nice to know what you want and how to get it. So I am still looking toward that end. I'm getting there.

It is a common misconception, but diamond plates do not hone faster than synthetic hones.
Quite the contrary actually.

A 1K norton for example has a very high surface density of abrasive material, and when honing, some will come loose and act as a slurry.
A diamond plate has a lower density of abrasive material, and when it is broken in, none of it comes loose to form a slurry.
The one thing that diamond plates have going for them is that they stay flat forever, and don't wear down when used properly.

If you want real speed, the best thing (imho) is to take something like a norton 1K, and then use a DMT to raise a slurry with a lot of abrasive material, and then hone on that 1K stone while leaving the slurry on top of the surface. It will remove metal very fast. Still, 'fast' is a relative term, and above 61 HRc, it would be more appropriate to use terms like 'less slow'

This is a very interesting thread but I have an observation. TI came out with their C135 steel which is, by design, engineered to be a very hard steel. The problems with that series of razors are that they take a certain amount of gymnastics to get a smooth, keen edge. I personally love the ones that I have but there are a lot of people that really dislike them because they never seem to be able to get a good edge on them and do not like the rigidity of the blade. I think this one of the major reasons that TI has not forsaken the traditional razor steels. There was talk at one time that TI was going to eliminated softer steels entirely but I think that they have met a certain amount of resistance to that. As Lynn mentioned above it is how a razor hones and how they shave. Very hard steel can be problematic from what I have personally experienced.

Take Care,
Richard

Originally Posted by Bruno

It is a common misconception, but diamond plates do not hone faster than synthetic hones.
Quite the contrary actually.

A 1K norton for example has a very high surface density of abrasive material, and when honing, some will come loose and act as a slurry.
A diamond plate has a lower density of abrasive material, and when it is broken in, none of it comes loose to form a slurry.
The one thing that diamond plates have going for them is that they stay flat forever, and don't wear down when used properly.

If you want real speed, the best thing (imho) is to take something like a norton 1K, and then use a DMT to raise a slurry with a lot of abrasive material, and then hone on that 1K stone while leaving the slurry on top of the surface. It will remove metal very fast. Still, 'fast' is a relative term, and above 61 HRc, it would be more appropriate to use terms like 'less slow'

Thats a bit strange, my 1200 DMT plate was worlds faster than a 1k Norton. It left deeper scratches, but it was much faster, especially if I used low pressure with both.

Originally Posted by gssixgun

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..

You will get a better answer from one of the blade smiths. But, I think it has a lot to do with our refinement and ability to control the process and the steels. You will still see this differential in hardening in some custom blades and you will recognize it because of the hamon line. I think it is primarily because of the method of quenching the blade. Edge is cooled faster than the spine and tang resulting in more hardness as you get nearer to the edge. It "freezes" the metal in the harder state and allows the rest of the blade to drop to a softer level before freezing.

Jeff

How many shaves, generally speaking, do you get from the razors you like the best, before an abrasive/honing is required? It may be due to less experience but I can tell you I am lucky to get a dozen shaves from each- even when properly rotating my blades and doing a dozen passes with linen and leather each morning.