General Question of Stropping and Honing my Dovo

The Dr. Verhoeven's research papers seems to have been withdrawn. Perhaps someone can google it and post it as its been posted and discussed numerous times on this site. DM
 
I will give that a read. I did do a search on Dr. Verhoeven and found several references. This one was perhaps most interesting.

Verhoeven conducted the leather experiments on flat hones and flat leather strops, using this jig, leaving the specimen blades attached in the jig during the entire honing and stropping progression:
bart-albums-my-album-picture1815-jig.jpg

(picture taken from page 18 with reference to the original article at http://mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdf)
He checked his results at 3000X magnification, using an Scanning Electron Microscope, and found no discernible diminishing of 6000 grit abrasive grooves.
That is as scientifically bulletproof as it gets. Verhoeven had to change his mind about leather: "(...), it was initially thought that a clean strop would contain enough natural abrasive material to produce a marked improvement in the quality of the edge. As a result, several initial experiments were done with clean leather strops,including an experiment with alternate 3 cycles of 4 leather stropping plus a single 6000grit sharpening. In all cases the clean leather stropping proved ineffective in comparison with the dramatic improvement found with the chrome oxide loaded strop." (page 22 of same document)
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I will re-read my posts, and see how I come across, but I have no issue with you or anyone else here. Nor am I dismissive of ANYTHING I have seen in the way of scientific studies.
 
I re-read my statements. I have attempted to conduct myself as professionally as possible here. I have been VERY careful NOT to state any of my findings as FACTS, and went so far as to state the limitations as I realize them. I offered suggestion to be CAREFUL repeating other (potentially dated) information read on the web as it may propagate myths.

You may disagree with me if you like. But David Martin, I would like to point out this quote to you once again
David Martin said:
...yet what members really wanted to do was slam it. Plus, never present evidence of their own.
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I am slamming NOTHING and NO ONE here, but you seem rather dismissive of me and quick to want to "lay this to rest" without presenting evidence of your own.
 
Here is another pretty interesting interpretation of Dr. Verhoeven's work:

Stropping a razor on a clean leather strap remains one of the most scientifically uncharted territories of the sharpening proces. In his - among sharpening adepts famous - knife sharpening experiments, Professor John D. Verhoeven of the Iowa State University ventured into some sideways research on stropping, but he could not reach much conclusive insights into the bare physics of stropping a knife's edge on leather that was not treated with any abrasive compound. Even though he inspected the edges with a Scanning Electron Microscope (SEM), he reported little to no evidence of physics at work. One could be inclined to start wondering whether stropping has any measurable effect at all. Yet, any experienced straight razor shaver will testify that the difference between a regularly stropped and an unstropped edge is very conspicuous. But even for those who like to attribute this to the mother of all placebo effects, it's impossible to dismiss the very clear improvement that can be found post stropping, in the way a single free hanging hair can be severed at any distance of the holding point. In short: while we can collect empirical evidence of stropping efficiency, we cannot witness the bare physics at work. That leaves us wit a lot of speculation.
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From this website: http://www.coticule.be/stropping-a-straight-razor.html

Perhaps it is all bunk, but is seems that this source derived different meaning from the paper referenced earlier in this thread...I am honestly puzzled as to why every link I have found to this paper is dead.

I will admit that I am simply parroting info from other websites here, but there seems to be some rather compelling discussions that are interesting to say the least.
 
...From page 24 (conclusion #3) of Experiments on Knife Sharpening, by: John D. Verhoeven, Emeritus Professor, Department of Materials Science and Engineering, Iowa State University. September 2004
Apparently, the natural abrasives in clean leather,
on either the hard or soft side of the leather, is not adequate to produce a significant
abrasion of the surface.
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DM, neither of the links are working, double check them to see if something was left out please.

David Martin said:
Plus, I've been on many discussion here which had well supported evidence put forth yet what members really wanted to do was slam it. Plus, never present evidence of their own. So, I don't take the bait any more. DM
Here's some evidence on stropping dating back to 1931. http://blog.modernmechanix.com/2008...spected-facts-about-razor-blades-and-shaving/
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David Martin said:
gadget, What I saw from the photos, supports your point 1&2. The article I submitted on stropping actually states this on pg.55 last paragraph, almost in your wording. On your point 3 I don't know. On your point 4, yes and much quicker than one might think. Like after 200 on a spongy material like leather. Still, is this a good or bad thing.--- I'm not sure. I'm currently shaving with a Feather blade (double edge) and its on shave #50. Is it convexed? Yes, but not as much as I've seen on my straight razor from stropping on plain leather as the double edge only sees stropping on paper backed with a hard surface. My experience, your mileage may vary. DM
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It was in general as I've seen topics start like that then go that direction.
Shucks, nothing works. I was doing a cut and paste to minimize any typing error.
 
I just did the modernmechanix link and it loaded right up with one tap on the touch pad... ? DM
 
I have tried it on a third machine now and I still get nothing. Who was the author and what was the date of the study?
 
To the point about oxidation, I fully agree that the strop is going to be removing that. I'm willing to leave the question of whether the strop is removing steel open. maybe it does in some cases, and not all? Any change is not going to be "significant" I'll grant you that as well. All I know from personal experience is that the window between a razor working and not is very small. Maybe it is a very tiny but important change? I've heard theories that the strop produces heat in the blade, essentially heat treating the last few molecules of the edge, before the heat is dissipated into the rest of the blade. This material oxidizes away, which is why you need to strop before each shave. I don't know if its true, sounds logical. raising or lowering the hardness of the steel even by a tiny amount may have a huge effect, if that is the important part. I don't know what is. Could it be the final cross-sectional shape of the edge, something I don't think I've seen photos of. could the vibration induced in the steel from the sliding over the strop have an effect? I have no idea on that either. I'm just tossing out ideas here, and I know we won't come to an answer. None of my blades look the least convexed, even after a few months of use. But maybe the change is too small for me to see, or maybe its only in the last few microns of the edge.

Leethal, as for the Fin thing, I think comparing it to a butchers knife doesn't really work, in one case you have a relatively soft steel being formed so that the edge is no longer in alignment with the blade, forming a burr. this can be pushed back into place by the steel, restoring the blade to useability. With a razor, you have a very fine weak edge, that if it were to form a burr, would simply drag over the leather until it was worn off. the leather isn't going to have enough resistance to actually burnish the edge. And if it were able to, then why doesn't the hair? The original idea of this Fin is that there is some extra bit of sharpness that comes from the crystals in the steel realigning themselves while the razor rests. And yet, it is quite easy to put a "wire edge" on a razor blade, and it is useless for shaving, it chips off, leaving a dull blade behind. The goal of a razor is to get as close to a perfect apex all along the edge. The better formed that edge, the easier it is going to be to cut through the hair. Also if you look at most of the instructions that have been found about straight razor use from the 1800s they are clearly marketing ploys. They are all different, all reference different techniques, and some seem to just be a way to sell more razors.

Links not working for me either. You may have them cached, or something like that. they are no longer available.
 
Gadget, you may want to Google the paper I referenced above (Verhoeven, 2004).
 
I've looked at the paper in the past. While I found there was a lot of useful info, I found that it didn't answer all of the questions. Just because something can't be found doesn't mean it doesn't exist. stropping does something, otherwise why do we do it? But I don't think that oxidation is the only factor involved here. If it is, then we should able to simply coat the blade with oil, and only need a hone every few months. Not trying to be flippant here, its just that one scientific paper is not the end all and be all of knowledge. I want to know why stropping works, I'm just not convinced its a simple answer.
 
Correct, the lack of evidence is not evidence. The Verhoeven paper was posted in the Maintenance forum like 2yrs. ago and we looked it over well back then. Remembering it didn't answer all our questions but we had a research paper. Careful reading showed he used suede leather during some of his stropping. I had this paper saved and now mine doesn't work. A better computer tech could find it and get it opened. Still, hundred of microscopic photos taken of stropped razor blades and the obvious stated is strong evidence as in the other link. Not to discount an individuals experience and observations over years of shaving with supporting evidence is good. Perhaps not as sound as hundreds of photos but not weak either. I'll send in another batch for photos. DM
 
Interesting.

You posted a link to a paper by the same man that was 80 years old in efforts to lay this to rest.

I then posted a link that revisits the topic and adjusts the conclusions accordingly to contradict the earlier claims (that you cited as support for your observations).

Interestingly enough I conducted independent studies (as has Glen M. a professional razor honer and restorer) that concluded the same thing that is in the paper with regard to leather NOT abraiding hardened steel.

I am starting to understand now...

FYI he used both rough and smooth leather strops in his study published in 2004.

I will again suggest that technique is important.

Stropping most certainly does do something to refine the edge, but it seems well demonstrated in several studies with various degrees of control and attention to detail (Verhoeven had the highest level of control and demonstrated such under peer review) that leather is not abrasive on steel.

Can an edge be convexed on a bare leather strop (beyond the initial honing finish stropping)? Yes, but it will be done do at the cost of edge life and is the result of poor technique, not abrasives in my opinion.
 
Yet again... When I refer to the "fin" I am talking about the very apex of the cutting edge. How can you say a raz
 
razor or any other cutting tool doesn't have a very thin apex. It's what sharp is. A triangular edge that draws out to Infiniti. When you use that tool, the very apex of the edge is "damaged" or rolled or chipped this getting dull. Whether you call it a fin or apex of the cutting edge is redundant because every knife or razor has one. What do you think I mean when I say fin?
 
Leethal Cutlery said:
razor or any other cutting tool doesn't have a very thin apex. It's what sharp is. A triangular edge that draws out to Infiniti. When you use that tool, the very apex of the edge is "damaged" or rolled or chipped this getting dull. Whether you call it a fin or apex of the cutting edge is redundant because every knife or razor has one. What do you think I mean when I say fin?
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What is this talk of "draws out to infinity". A triangle is very finite. An edge is also very finite and the best methods of sharpening known and the best steels will result in apex thicknesses of ~0.3 to ~ 0.5 microns and is not a point.

If you succeed in grinding a thinner apex, it will crumble and degrade.

There are numerous sources of magnified edges available. Including the references in this thread.
 
Good points in this thread challenge my view (silicates do abrade edge) about bare leather stropping.

What is the effect of stropping on bare leather to a clean (free of wire/burr/pre-burr) edge?
a) minimal (insignificant hence treat as nothing).
b) noticable performance change due to combination of abrade, plastic-flow/burnish, nano temper, ..
Note: From Dr. Verhoeven's research paper fig 7 & 9 edge-view, those edges have pre-burr (I called them lip), therefore not clean.

For the answer, I did 3 informal experiments:

Setup:
Endura4 vg-10 30* inclusive clean apex est 200-300nm thick by edge-lead sharpened into surfaces embeded diamond particle size 12um progress to 0.1um. This edge is clean because after a few one-sided 90* scraped into balsa - it's still shave & cut tp cleanly.

Horse butt leather: 6 month old strop, brand new strop, 5x1.5" clean scrap

Experiment1:
Stropped knife to 6 month old strop at 70*/side (140* incl) for 10 minutes.
=> no longer produce a clean dry-shave, failed tp cutting.

Experiment2:
Stropped knife to brand new strop at 70*/side (140* incl) for 10 minutes.
=> edge almost unchanged. Still clean dry-shave, tp cutting.

Experiment3:
Stropped knife to 5x1.5" clean scrap leather at 90*/side (perpendicular to leather) for 10 minutes, applied only to 1.5" next to the knife heel. I used enough pressure to destroyed leather top-layers and got quite abit of leather powder.
=> experimented part of the edge is as sharp on the un-touch part. Still clean dry-shave, tp cutting.

Woah :confused:! The answer is (a) but what's about the result of experiment1?

I think my 6mo old strop is polluted with abrasives and swarf over the 6 months from frequent usage. Abrasives & swarf could have deposit there by handling and losen from entrenched in scratches.

To all - please do some experiments to prove otherwise, so I can keep my current view - although feeling a bit 'old' :D
 
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