Thread: Verhoeven Paper Question

He actually stated that he used commercial and paddle strops. He did not mention the word hanging. I would then assume that he was using leather glued to wood. Which is what I think he states was done on preliminary tests.

So what about the other questions?

Originally Posted by JimmyHAD

I only know that I can take a razor that doesn't cut hanging hair and do my 50/50 and then it does. Not always but a lot of the time.

I think it's the linen that's doing the work of sharpening the razor though. You'll notice that he also tested felt strops and they did sharpen the steel. He didn't test linen but I suspect they work similarly to the felt.

What I think the leather does is straighten the edge from the banging it gets on the rough linen. I agree with Verhoeven that the leather doesn't sharpen, though I suspect that after awhile it may get enough oxidized steel embedded in it that it may be abrasive. And it's possible that a heavy-drawing strop may be able to break off the oxide bloom from the edge, though I don't like heavy-drawing strops so I can only speculate wildly here...

Originally Posted by singlewedge

2. He never stated that he took the edges to a good cutting edge, shave sharp or otherwise, did I miss this section?

He does test a commercial gillette blade and a straight razor honed by somebody that shaves with one at the very beginning of the article.

Originally Posted by singlewedge

4. Why was he going for a smooth bevel? I thought it was the edge that cut? Does the smoothness of the bevel translate to a better edge? Couldn't you have a smooth bevel and a rolled or otherwise blunted edge?

I think the mentions somewhere in there that the smoothness of the bevel relates to the amount of resistance felt as you cut, since this changes the friction of the blade against the subject. You can also coat the bevel with a friction-reducing substance to achieve a similar effect, which is what the commercial razor manufacturers do. A smooth bevel won't compensate for a dull or rolled edge, but its an important factor after edge width. This is why he also looked at burrs and measured the edge thickness on most of the photos. BTW he mentions in a note in the article someplace that he measured the edge thickness at 10,000x power, much higher magnification than the photos show. He also discovered that there's a definite limit on how thin you can get the edge, so once you've gotten to that level of sharpness then bevel smoothness becomes much more important. Since he was able to achive this minimum edge thickness even with relatively coarse stones (~4k grit) this explains why a fine-grit razor hone improves a razor's sharpness - it polishes the bevel and reduces the cutting friction.

Originally Posted by mparker762

I think it's the linen that's doing the work of sharpening the razor though. You'll notice that he also tested felt strops and they did sharpen the steel. He didn't test linen but I suspect they work similarly to the felt.

What I think the leather does is straighten the edge from the banging it gets on the rough linen. I agree with Verhoeven that the leather doesn't sharpen, though I suspect that after awhile it may get enough oxidized steel embedded in it that it may be abrasive. And it's possible that a heavy-drawing strop may be able to break off the oxide bloom from the edge, though I don't like heavy-drawing strops so I can only speculate wildly here...

It's been about a year and a half since I read the article. Did he conclude that plain unpasted wool felt (animal hair) actually sharpened the steel but leather, animal hide did not? Would your suspicion regarding cotton or linen plant fibers having steel sharpening potential be unpasted plain "linen" or pasted with something? That would seem odd to me that a plain unpasted plant fiber or animal hair could sharpen steel but leather could not.

Chris L

Originally Posted by singlewedge

I read the section on stropping and hand honing. I guess after that I have several questions that were not either answered or addressed.

1. He stated that regular leather strops had no effect on smoothing the edge, but that a regular leather strop with Chrom Ox had a great effect of smoothing the edge. I assume that he used cow hide because he stated that he used commercially available leather from a shoe store. What about Horse hide, Latigo, Russian leather? Aren't they all leather? Is he stating that any leather, when treated with chrom ox, is better than leather alone?

He stated that clean leather doesn't significantly reduce burs that are the result of honing. He concludes that leather only has very limited abrasive power. I think he's correct. But I don't think Verhoeven is talking about shaving with his edges. Verhoeven measured the width of the edges on razors and commercial blades, finding typical widths in the 0.5 micron range. That leaves us with a 0.5 micron strip of erratic steel on top of the edge. I think that narrow strip is ductile enough to be alligned with friction. Clean leather seems to be just the appropriate surface for generating that friction. We all notice a clear performance improvement, coming off the strop. All my razors pass the HHT after stropping, while they loose that ability during the shave, only to gain it again with my next stropping. Stropping is just that, alligning steel and nothing else. If there was any metal removed, your strop would be loaded with that after extended use.

2. He never stated that he took the edges to a good cutting edge, shave sharp or otherwise, did I miss this section?

Verhoeven conducted experiments on knife sharpening. He refers to razors, and uses commercial razor blades where that fits into his experiments. But his methods and approach are aimed to knife honing. (hone on one side till a bur is present, next flip the blade and hone to remove the bur). He only measures the width of the resulting edges and leaves it there.

3. It seems that the waterstones with Nagura gave a better result than the man made stones. If this is true then why would I buy a Norton 4/8 besides the money?

If I understand it correctly, the Norton 4K/8K is a japanese style "waterstone", formerly made in the USA and recently in Mexico (if I'm informed correctly). Verhoeven's research favors those hones over diamond hones, such as those produced by DMT. (it is only fair to state that DMT uses monocrystalic diamonds, as apposed to most other brands of (polycrystalic) diamond hones, and that we don't know which type Verhoeven used)

4. Why was he going for a smooth bevel? I thought it was the edge that cut? Does the smoothness of the bevel translate to a better edge? Couldn't you have a smooth bevel and a rolled or otherwise blunted edge?
The smoothness of the bevel translates to the keenness of the edge. You can have a smooth bevel and a dull edge, but you cannot have a deeply scratched, rough bevel and a keen edge.

5. He stated that the Japanese stones worked best on 60 Rockwell stainless. Does anyone know what the Rockwell of carbon blades are?
The hardness of most high carbon steel blades varies between 55 and 62. Verhoeven limited his statements about waterstones to HRC 60, because that was what he tested with. He didn't say anything about the performance of those hones, on steel with a lower HRC, but it's safe to assume the results would be equally great. With HRC above 62, it's possible that diamond hones have an advantage, because diamonds are harder than whatever abrassive particles used in waterstones. I think Verhoeven only tried to be accurate with his statement about 60 HRC.

6. He used a compound bevel for his edge 9 degrees more on the 600 and 7 degrees more on the 1000. Is a compound bevel useful on a str8? How would one place a compound bevel on a str8? Electric tape comes to mind to adjust the angle.
Tim Zowada uses it on his razors, adding 2 or 3 layers of tape to create a very narrow microbevel. Other members, including myself, have experimented with it. I believe SRP member Jockeys made a honing video where he shows how it's done.

Thanks guys.

Best regards,
Bart.

Originally Posted by Chris L

It's been about a year and a half since I read the article. Did he conclude that plain unpasted wool felt (animal hair) actually sharpened the steel but leather, animal hide did not? Would your suspicion regarding cotton or linen plant fibers having steel sharpening potential be unpasted plain "linen" or pasted with something? That would seem odd to me that a plain unpasted plant fiber or animal hair could sharpen steel but leather could not.

Yes, plain hard felt did sharpen the edge - this could be clearly seen under the microscope. He was stropping with the blade slightly inclined, so the felt produced a secondary bevel, but presumably had he not elevated the blade it would have slightly abraded the entire bevel. My belief is that the linen strop acts similarly, though I don't *know* this for a fact. I did an experiment once where I intentionally dulled a razor with cardboard, then brought it back to shaving condition by stropping on the linen. Either the strop is "drawing out" the steel or it's abrading the metal away. Verhoeven didn't find any "drawing out" effect in any of his stropping test (pasted, leather, or felt), so I'm inclined to believe abrasion is the most likely explanation. I don't know why hair/plant fibers are abrasive while leather isn't, that's just what he found.

Verhoeve was actually looking at leather to investigate the belief that leather stropping breaks off the burr caused by overhoning. This is how chisel and knife sharpeners tend to sharpen things - they sharpen till a burr is formed, then strop it off. But Verhoeven found that leather didn't even remove the burr, much less remove any steel along the bevel. But the felt strop did remove the burr and abraded the metal along the edge. There was a distinct difference in the abrasion patterns caused by the felt vs the pasted leather - the felt seemed to leave a rougher abrasion pattern, but IIRC it was a slower abrasive than the 0.5 chrome oxide (from what I recall from looking at his secondary bevels after similar # of laps).

Originally Posted by mparker762

Yes, plain hard felt did sharpen the edge - this could be clearly seen under the microscope. He was stropping with the blade slightly inclined, so the felt produced a secondary bevel, but presumably had he not elevated the blade it would have slightly abraded the entire bevel. My belief is that the linen strop acts similarly, though I don't *know* this for a fact. I did an experiment once where I intentionally dulled a razor with cardboard, then brought it back to shaving condition by stropping on the linen. Either the strop is "drawing out" the steel or it's abrading the metal away. Verhoeven didn't find any "drawing out" effect in any of his stropping test (pasted, leather, or felt), so I'm inclined to believe abrasion is the most likely explanation. I don't know why hair/plant fibers are abrasive while leather isn't, that's just what he found.

Verhoeve was actually looking at leather to investigate the belief that leather stropping breaks off the burr caused by overhoning. This is how chisel and knife sharpeners tend to sharpen things - they sharpen till a burr is formed, then strop it off. But Verhoeven found that leather didn't even remove the burr, much less remove any steel along the bevel. But the felt strop did remove the burr and abraded the metal along the edge. There was a distinct difference in the abrasion patterns caused by the felt vs the pasted leather - the felt seemed to leave a rougher abrasion pattern, but IIRC it was a slower abrasive than the 0.5 chrome oxide (from what I recall from looking at his secondary bevels after similar # of laps).

Could you point me to the phrases where Verhoeven talks about stropping on felt (other than on felt wheels loaded with abrasive compound), and to the parts where he compares felt to leather loaded with abrasives?
Could you also point me to the phrases where Verhoeven tested the "drawing out" effect and found nothing?

It seems that we are reading different documents, or at least a different version. The one I thought we were discussing is here:
http://www.bushcraftuk.com/downloads...nifeshexps.pdf
and also here (same document):
http://mse.iastate.edu/fileadmin/www...nifeShExps.pdf

Thank you,
Bart.

Here's the man:
John Verhoeven

and his reputation.

Originally Posted by Bart

Could you point me to the phrases where Verhoeven talks about stropping on felt (other than on felt wheels loaded with abrasive compound), and to the parts where he compares felt to leather loaded with abrasives?
Could you also point me to the phrases where Verhoeven tested the "drawing out" effect and found nothing?

It seems that we are reading different documents, or at least a different version. The one I thought we were discussing is here:
http://www.bushcraftuk.com/downloads...nifeshexps.pdf
and also here (same document):
http://mse.iastate.edu/fileadmin/www...nifeShExps.pdf

Thank you,
Bart.

Hmm, we're talking about the same document. I just went back through it searching for "felt" and it appears that I was mistaken and he used the white bar on the felt and cloth in all experiments.

BTW I've used the white bar on my linen strops with success. It's a submicron tin oxide (some variant of Linde polish) and it works just fine. Just rub it on like a crayon. It seems to act like the Dovo white paste, and it wouldn't surprise me to discover that the Dovo stuff is just repackaged Linde paste. The white stick is available at any decent-sized hardware store for about $3, and it won't leave green stains like chrome oxide.

Verhoeven never specifically talked about any "drawing out" effect. But it doesn't show up in any of his photos, and he never mentions such a thing in the article that I recall (though I'm beginning to suspect my recollection). He did mention that the leather strop scratched the blades some (possibly dust on the leather), but otherwise had no effect.

Did Mr. V publish info on the edge dimension after leather stropping, or as i recall he only observed the scratch pattern to be little changed. while abrasive strops were more instantaneous.

The point as he states was to discover the best way to remove the "bur" ;matching the straight razor standard .3 micron edge was the best one could look for. (except for John J's .1 micron steeled folded bur) For our purposes his best solution would be 6k to pasted strop.