Thread: strop scratches

It sounds like an error in the process you use to evaluate scratches. Let's spend some time here. The scratches don't ever "go away" no matter what grit you use. There is a well known optical illusion referred to as "black ice". Could that be what you're seeing? Carefully micro-observe the bevel at various angles before stropping to verify that the scratches are really going away.

What is your hypothsis regarding how the 8 k scratches are getting on the blades? How can the strop scratch the blade and just happen to match 8k?

I suppose they are both pretty smooth but please double check your results. Years ago when I looked at stropping under a scope it looked more like a new cross-hatch pattern, not the angular striations associated with a stone.

All razors honed at 8k or higher do feel the same to me. So you've got that working for your theory.

Originally Posted by mdarnton

Three of the leather strops are new, real commercial strops. One of them I sanded down, just to see if there was something caught in it. Of the bunch, I think that my belt does the cleanest job.

I think this may be the culprit, especially if you are seeing an obvious new scratch pattern. I finish on a very fine stone & sometimes I see a random scratch from the strop but not to the degree you describe.

Have you checked after the CrO also ? Strop scratches will also run in the opposite direction to stone scratches. Just something else to check.

Originally Posted by AFDavis11

It sounds like an error in the process you use to evaluate scratches.

I really don't think so. I'm doing this pretty critically--give me a bit of credit here. For one thing, the scratches start sparse, about the depth, not the frequency, of 8000 grit. Then as I strop, they increase in frequency. I've tried various angles, and the scratches form at the angles I'm stropping. I'm not a sharpening newbie--I've been doing it for 30 years and Ido know what I'm seeing. And as I said, it's happening with every strop, not just the one I sanded, not just the new ones, the old ones.

What I'm not looking for here is various people who've never bothered to look for themselves telling me I'm imagining things. That's really not very helpful.

I guess I'm going to have to solve this one myself.

Originally Posted by onimaru55

Have you checked after the CrO also ? Strop scratches will also run in the opposite direction to stone scratches. Just something else to check.

I have chromed on glass, just to avoid contamination, to the point where there are no scratches at all, and then stropped and watched the scratches form. As I said, on fresh newspaper, too.

How do these scratches affect the edge ? Any visible damage ? Shave test bad ?
Leather does contain silicates so scratches would be obvious on a highly polished bevel but hard for us to get an idea of what you're seeing without microscope pics.

Originally Posted by mdarnton

I really don't think so. I'm doing this pretty critically--give me a bit of credit here. For one thing, the scratches start sparse, about the depth, not the frequency, of 8000 grit. Then as I strop, they increase in frequency. I've tried various angles, and the scratches form at the angles I'm stropping. I'm not a sharpening newbie--I've been doing it for 30 years and Ido know what I'm seeing. And as I said, it's happening with every strop, not just the one I sanded, not just the new ones, the old ones.

What I'm not looking for here is various people who've never bothered to look for themselves telling me I'm imagining things. That's really not very helpful.

I guess I'm going to have to solve this one myself.

That's not exactly a great attitude to have when asking for help. I have looked at my blades under a USB microscope after honing, and after stropping. I see scratches off the strop too, but, the shave is significantly more pleasant off leather.

You never answered my question though.

I've looked at blades at all stages of the sharpening process under magnification of up to 1000x.
I have not observed an increase in scratches from stropping on plain leather.

What type of microscope are you using, how is it lit, and what magnification?

Originally Posted by mdarnton

From what I'm reading, I'm gathering that people have been advocating sharpening methods that they've never really examined to see what's going on, on the theory that throwing more money at a problem solves it better?

This is incorrect.

Ok. Since you're tossing me into the group that has never looked at an edge, with a scope, I'll stay out of it.

Originally Posted by mdarnton

I really don't think so. I'm doing this pretty critically--give me a bit of credit here. For one thing, the scratches start sparse, about the depth, not the frequency, of 8000 grit. Then as I strop, they increase in frequency. I've tried various angles, and the scratches form at the angles I'm stropping. I'm not a sharpening newbie--I've been doing it for 30 years and Ido know what I'm seeing. And as I said, it's happening with every strop, not just the one I sanded, not just the new ones, the old ones.

What I'm not looking for here is various people who've never bothered to look for themselves telling me I'm imagining things. That's really not very helpful.

I guess I'm going to have to solve this one myself.

I've looked at bevels under all kinds of magnification and have never been able to draw much of a connection between residual scratches in the bevel sides and the quality of the resulting shave. The bevel sides do get shinier as one progresses upward in grit, especially as one approaches and passes 8K. My personal results have never shown any degrading in that shiny effect as a result of stropping. On the other hand, I have not seen any particular connection between a shiny bevel and a good edge. To me, they are two separate issues. It is possible to have a beautifully shiny set of bevel sides that do not meet properly in a good edge when the bevel is not set. I tend to concentrate much more on how sharp the edge appears to be with visual tests and the HHT. I don't have a lot of time for "test shaving", so I use the HHT to save me the time. I've never gotten a positive HHT result that was followed by a less than excellent shave.

Ace, yes, I understand. I'm not implying the shaving is better or worse--I'm just curious about the scratches. This is a technical question, and what is really happening at that level of examination, not one about shave-readiness. Thanks.