Thread: Hypothetical secondary effect of stropping

Gentlemen, for your consideration:

A hypothetical secondary effect of stropping.

The conventional wisdom regarding stropping is that it aligns and straightens microserrations along the razor’s edge.

It has been observed that with several cycles of shaving and stropping, the edge improves after honing before reaching a point where the keenness of the edge declines thus requiring honing or pasting.

Since plain stropping does not seem to be removing metal only moving it, the question is raised regarding work hardening of the metal.

Work hardening is a well known and readily observable phenomenon. When metal is manipulated, that is bent or hammered, it becomes harder. This can easily be demonstrated by bending a paper clip back and forth. The clip quickly loses its ductility (if ductility is the word I want) until brittleness overtakes it and it snaps.

Or, one could repeatedly strike a copper penny and observe that more deformation occurs with the initial blows and that further shaping becomes difficult as the copper becomes harder.

So:

Does stropping harden the edge of the razor? Does this explain the bell curve of shaving comfort? Does the edge become harder to the point that it starts becomes too brittle thus requiring honing to expose fresh steel?

Does a slack strop strop bend the edge more causing a greater hardening?

I’ll leave it to better minds to ponder. I’m just an idea man.

Happy trails,
LG Roy

interesting idea. Sounds like it could have a point....unfortunately I'm not much of a metal man....so I can't really say if it's true.

Now that's a perfect example of thinking outside the box. Good brain, LG.
I've got no answer either, but I sure will ponder this one and await the metalurgists to weigh in.

X

The scyte is also hammered between honings. that makes sence...

My take on it, for what it's worth:

Work hardening requires overstressing a metal. Low carbon steel and stainless steel are two that can work harden rapidly when deformed beyond their normal stress tolerances. Stropping can't possibly provide enough heat and stress to cause work hardeining.

Instead, consider this. Stropping DOES remove and shape th metal. It does it at a slower rate than hone, by far, but leather will definitly polish metal and polishing is caused by removing metal at a micro-scale. This forms a very fine micro bevel, which is more obtuse and, therefore, more risistant to dulling. Until the micro bevel becomes so large and obtuse as to restrict the cutting ability of the edge, the edge will continue to become a little stronger and a little more durable with each time the blade is stropped.

I have not made up my mind if stropping does work harden it or not. As papa bear pointed out you have to stress the metal and deform it. to get work hardening you really have to exceed the yeild stress of the metal. This does happen when you strop. If stroping moves the "teeth" so that the "teeth" do nto spring back to their original position then stropping does create stresses that exceed the yeild stress of the steel. In that case I would expect the metal to have been work hardened some.

I'm with Robert. I think the blade does reform with stropping. And I think we are just beginning to understand the benefit of extra stropping passes and more aggressive stropping.

Originally Posted by trapperjohnme

If stroping moves the "teeth" so that the "teeth" do nto spring back to their original position then stropping does create stresses that exceed the yeild stress of the steel. In that case I would expect the metal to have been work hardened some.

That would mean that shaving work hardens the steel, too, then. Because it moves the "teeth" out of alignment so they don't spring back to their origninal position. Cutting or dulling of a blade doesn't work harden it, so I think there's little chance that stropping would stress the metal enough to work harden it - at least to any practical degree. I don't think that the purpose of stropping really is about realigning the "teeth" so much as polishing the micro-bevel with the silica naturally in the leather, which is a very mild abrasive.

I'll have to go with you on this one PapaBull.

That would mean that shaving work hardens the steel, too, then. Because it moves the "teeth" out of alignment so they don't spring back to their origninal position

that is correct pappabull it would.
But who is to say that saving doesnt work harden part of it?
You have to realize that you can work harden an incredible small area. moving the tooth of the razor either by shaving or stropping will cause work hardening somewhere if the yield stress is exceeded, most likely the root of the tooth, not the very edge. So even though work hardening is occuring it may not be close enough to the edge to benifit.


working high carbon steel to the point that the yield stress is exceeded will result in some work hardening were the stress is great enough to exceed the yield stress, that is just a law of physics.

Work hardening is not always a good thing. Fatigue failures in moving parts are due to a larg extent on localized work hardening.

As a matter of fact one way of dulling a blade is the "teeth" breaking off, they would be more prone to do this if they had been work hardened.