Thread: CPM M4 steel for razors

Sorry for the delay.
I could see how for supersteels, you need to go to diamond.
For regular steels, I find that using a DMT to raise a slurry on the norton 1K gives a very aggressive slurry.
Additionally, there are no deep scratches like from a DMT325.

The coarse diamond for bedding/leveling/slurry is on the way. Thanks for the recommendation.

It is becoming clear to me that the primary consideration for razors over their history has been sharpen-ability. (Assuming the primary influence on shave-ability is blade sharpness).This was not so obvious (to me) before but makes perfectly good, even common sense now that I am dealing with it. One abrasive manufacturer even noted that their aluminum oxide lapping compound was recommended up to an HRC 62 hardness for steel; implying a diminishing return for those honing something harder.

This also implies our razor steel technology was limited by our abrasive technology; not visa versa. Our great-grandfathers could have made "better" steel, but the abrasives were not commonly available to deal with it if they did, combined with the value added labor costs of such a blade would likely make that razor a white elephant. Fortunately for us, other options are present or emerging.

Originally Posted by spacetransient

The coarse diamond for bedding/leveling/slurry is on the way. Thanks for the recommendation.

It is becoming clear to me that the primary consideration for razors over their history has been sharpen-ability. (Assuming the primary influence on shave-ability is blade sharpness).This was not so obvious (to me) before but makes perfectly good, even common sense now that I am dealing with it. One abrasive manufacturer even noted that their aluminum oxide lapping compound was recommended up to an HRC 62 hardness for steel; implying a diminishing return for those honing something harder.

This also implies our razor steel technology was limited by our abrasive technology; not visa versa. Our great-grandfathers could have made "better" steel, but the abrasives were not commonly available to deal with it if they did, combined with the value added labor costs of such a blade would likely make that razor a white elephant. Fortunately for us, other options are present or emerging.

I think you overestimate their steel making qualities.
Supersteels rely on the ability to add and control the precise amount of special alloys that were largely unknown at the time, and which could not readily be processed or alloyed.

For example, these days we know how to make wootz steel because we know the alloy elements and we know how to steer the process.
When people made the original wootz, they lucked out on trying the right process with the right ores. Sometime after that, the original ores were no longer available, and the secrets of wootz were lost because smiths could no longer produce it and pass the process on. They knew it had to be something about the ore, but had no clue what or how to determine the right ore.

Back in the day, they used simple carbon steel because that was what they could produce reliably turn out due to the simplicity. It's all they had. They were not held back by abrasives. They just didn't have the technology or the knowledge to reliably make supersteels, nor the heat treatment capabilities needed for such steels.

It doesn't make sense either to go much harder than 62 anyway. 62 is plenty hard enough for anything to do with cutting. For all other applications, there are more important properties than hardness. Toughness and impact resistance for one. Those properties are extremely important in construction, making trains, etc. If they had had the ability to make supersteels, they would have used them for making trains and steam engines.

"I think you overestimate their steel making qualities."


I really enjoy reading your historical accounts. Undoubtedly there was a lot of luck as well as trial and error going on in the past that can be far more reliably and scientifically produced today.

And it is certainly beginning to look like for razor sharpness, an HRC of 62 with some, (but not high content) wear resistance alloys may be the point of diminishing returns for our current (affordable) stones and other honing abrasives. 1%-4% Vanadium perhaps? Nitrogen and or Niobium added?