Thread: Does Stropping Speed Matter?

Hi,

I had a chat with Jerry when he came to the UK to shoot at Bisley a few years ago.He is a nice guy,very helpful. We were both shooting S&W 625's in .45 ACP. He reminded me to check the hammer spring tensioning screw, adding "your life may depend on it". Adding "On second thoughts, if your life depends on it use a shotgun".

Thats MY sport! I've been shooting IPSC with a revolver for years. Still not up to Jerry M.'s speed though. I usually beat half the field with autos though.

Originally Posted by Quick

Not sure I buy that Bart. I think the main contribution of speed in this context would be zero (static friction) or non-zero (kinetic friction). After that there may be some difference due to plastic deformation of the strop surface. If we imagine the strop surface to be pliable and bumpy then at a faster speed (same downforce) the razor may "skim" across the tops of the bumps rather than slower when the bumps have time to deform and flatten slightly. If there is any effect like this then going slower would result in more friction due to more surface area being in contact.

Quick,
I see you point, but you forget one factor that I think is important in the process of stropping.
Are you familiar with the concept "carpet burn"? It's a typical childhood injury. A good sliding over a carpet grazes one or more layers off the skin away. Making the same slide slowly will not have the same effect. I think it is because the energy is allowed to dissipate.
Now, before anyone gets the idea that I think stropping is about heat build-up: I don't. Not as such. But when we're talking about stropping, notions like steel displacement at a molecular level, polishing forces, superficial friction and heat distribution, are all very closely related, if not the same.
Friction, other than abrasion, has a timing component. If you see stropping only as an abrasive action, than it must be time (speed) independent. But if you look at it, like I do, more as the result of kinetic friction, than speed must be one of the factors, by mere definition of that physical principle (as you already pointed out in your first sentence of your post).

Apart form all this theory, I think we all can testify that stropping becomes more effective with some speed. It doesn't take much though, and I certainly am not advocating that faster stropping automatically produces better results. Only that effective stropping takes at least some speed.

Bart.

I didn't write that first sentence too well. The "zero" and "non-zero" were referring to speed.
At rest (zero speed) you need to overcome static friction.
Once moving (non-zero speed) you need to overcome kinetic friction (usually less than static friction).
Doesn't have much to do with the discussion though unless maybe there is a "stutter" effect when stropping slowy enough that the strop grabs and releases the blade surface.

Here is an alternative thought. The very edge is quite fragile. Not sure what damage from shaving looks like but I assume it involves (at least in part) some deformation along with chipping. If the surface of the strop is pliable it may have some "plastic" qualities as well. Think of dragging the very tip of a pin, which has been bent at a right angle, through something like rubber. If it is moved very slowly it either scratches the rubber surface or the rubber sort of flows around it. If it is moved quickly the tip of the pin just snaps off. How about something like that?

I've found that my tech. matters more than speed alone. I go as fast as I can while still keeping a good stroke. If I go fast and use a sloppy stroke it doesnt matter how fast I've gone I will wind up with a bad edge.