Thread: CPM M4 steel for razors

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

+1 knives are meant to cut 'things', not 'you'. razors are meant to ride the fine line of cutting in between the toughness of a whisker and the softness of skin. the toughest whisker is still much softer then the softest razor steel. a razor is a balance of hardness that sees the whisker as no challenge but has enough softness and flexibility to ride over the skin without trying to dig in. a steel that is not stubborn to being sharpened for the convenience of the user. it actually almost seems that the perfect steel would be of the minimum hardness it takes to give a good shave (assuming light maintenance, stropping) over however long you as a user feel is acceptable to have to touch up on the hone. remember the softer the steel the easier the touch-up would be as well so you might not mind doing it more frequently.

for example someone who enjoys honing may prefer a softer steel.

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.

Never mind- I did the search here and found members are typically getting 2x-4x the number of shaves I get out of a razor. Hence my looking into harder and more wear resistant steels. I would sure like to find a balance of edge holding and sharpenability that works for me.

Your trouble is likely just that you are a beginner, and not the steel or heat treat of your razor. I'm getting 2-3x more shaves between touch-ups now that I have 2 years of experience than I did when I had 3-6 months of experience. I also tried harder razors (including the TI 135 steel). It gave me about a 20-25% more shaves between touch-ups. Not 200-300% more...

Here's some things to try:
Make better lather. Double the amount of soap you are using, and use 1.5 times more water. You should end up with very wet, but thick lather.
Do better prep. Let the lather sit on your face for about 2-3 minutes before shaving. For me, this is the amount of time it takes to strop.
Strop better. Use just enough pressure you can feel the leather's texture. Do 30-40 round-trip laps on the nylon webbing, and 50-60 on latigo leather. Then do 10-15 more very lightly on the leather.
Shave better. Keep the spine 2 spine widths away from your face on WTG, and 1.5 widths away on XTG. Hold the heel 1/2-3/4" lower than the toe, but shave straight up and down (this puts the blade at a slight angle to the path of the shave). Concentrate on using no pressure.
Touch up the razor with 20 laps on a paddle strop with a light dusting of .5 micron paste when you start to get a little irritation (skin feels sensitive after shaving). If you wait longer, you'll start to feel pulling when you shave. If you wait even longer, you'll eventually get a rash-like razor burn.

Good Luck.

Originally Posted by spacetransient

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.

good question... i have no idea since i have enough razors that i have only ever had to hone each once and may never have to re-hone them again.

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.