Thread: Hypothetical secondary effect of stropping

If work hardening can be upheld, heat treating could be proven to be irrelevant Nice soft steel that's easy to hone would work just fine since the edge is hardned by stropping, right? Lead process heat treating.... what a bunch of nonsense .....I always did think the French were a bunch of big fat stewpid loosers, anyway.

How good a blade we have is more determined by the quality of the heat treat than the quality of the steel, itself. Two blades of the same steel can be perform very, very differently and that's all dependent on the heat treating.

I've taken some old beaters and drawn them down with a torch and re-treated them. It's pretty interesting to see it work and to see what it takes to harden steel.

Originally Posted by PapaBull

If work hardening can be upheld, heat treating could be proven to be irrelevant Nice soft steel that's easy to hone would work just fine since the edge is hardned by stropping, right? Lead process heat treating.... what a bunch of nonsense .....I always did think the French were a bunch of big fat stewpid loosers, anyway.

How good a blade we have is more determined by the quality of the heat treat than the quality of the steel, itself. Two blades of the same steel can be perform very, very differently and that's all dependent on the heat treating.

I've taken some old beaters and drawn them down with a torch and re-treated them. It's pretty interesting to see it work and to see what it takes to harden steel.

This makes sence to me.

Originally Posted by PapaBull

How good a blade we have is more determined by the quality of the heat treat than the quality of the steel, itself.

The good razor steel has to have at least 0.6% carbon in it, very important variable in the steel quality equation. Without it, all the heat treating in the world wouldnt produce shaving edge...

Nenad

If work hardening can be upheld, heat treating could be proven to be irrelevant

in a word no.

Again any work hadening that accorus would occur mostly at the root.

the other reason that heat treating is needed is it assures a uniform hardness. when a metal is work hardened the work hardening is proportional to how much it has been deformed. stroping does not creat uniform deformation throughout the razor, it doesnt even cause uniform deformation thoughout the teeth. the largest stresses would occur at the root that woudl tend to act as a cantilever as it is dislocated.

the hardness of the razor is most determined by the carbon content and the heat treating process. yes, it should have a carbon content of at least .6% also important in the quality of the edge is the carbide distrubition as well. this can be affected by alloying agents, processing of the steel etc.

I may not be an honemeister or a razor expert, but i am an engineering professor that teaches materials science and mechanical design.

Originally Posted by trapperjohnme

Again any work hadening that accorus would occur mostly at the root.

This might be a bit of a misleading way of putting it since we're really talking about grooves, striations.

Trapper, I was trying to make a point. I certainly wasn't seriously implying that heat treatment is irrlevant. That's what makes a razor's edge hard enough to hold up or not. Stropping merely polishes a more obtuse secondary micro-bevel which makes the edge stronger. But that's just from an engineering perspective. From an alchemist's perspective, work-hardening the teeth of a razor by stropping it is what makes a razor's edge durable. I'm not much into alchemy, though.

I think it's important in a discussion like this that we look to the relevant experimental data that we can get our hands on. The best electron micrographs of the razor's edge are from Prof. Verhoeven's paper "Experiments on knife sharpening." He has micrographs of straight razors. These micrographs show no evidence whatsoever of "teeth", but instead just a clean smooth edge that is about 0.3-0.4 microns wide.

I agree that stropping definitely does something, but what that is I don't exactly know. I don't think I would rule out work hardening at the very surface of the metal. While we are clearly not bending the metal back and forth, we are putting shear stress on the metal at the razor edge by dragging it across the leather. I suspect that it is possible to introduce lattice strain and defects which produce a harder 'skin' on the edge. It might be possible to observe this with a transmission electron microscope (TEM).

E

It's all very interesting, but there's no reason to reinvent the wheel. The existence of the teeth is well established. It's not the striationsbut the raised part next to it. The micrographs we saw were probably too close to see the striations. If you worked an edgw with a 8K stone, magnified 10,000x the spacing between striations would be 1.2 inches.

There is a old German story that razors should not be stropped right after shaving because it doesn't allow the teeth to return to their normal, nearly upright positions. Stropping would then force the teeth back, eventually causing them to break off from stress. This tells us that the teeth are elastically deformed when we shave and slowly return to some position short of being aligned. After that stropping probably causes additional elastic deformation as the teeth are stood up. This can go on for many shaves, and it does. Eventually, the blade pulls a little even after stropping. That's because of the slight frictional wear caused by shaving. All you need to do is a few touch up swipes on a Swaty and you're back to the original condition after you strop. As we know, this can go on indefinitely without major stropping.

So, with the normal routine, there should be no work hardening and no major honing required. That only happens if we do something out of the ordinary lkie, according to the Germans, always stropping right after you shave.

As for an edge improving after a few hone/strop cycles, that could just be a function of zeroing in an edge that's not quite there.