Nano grit sprays on Tony Miller practice Horsehide and Paragon Steerhide

[dakotaev]

Thanks for the updates again, the info is great.

 

[ken123]

Excellent thread. Hope you don't mind if I just sit back and marvel at the work and observations 'you guys' are making. Excellent thread.

---
Ken

 

[Kentos]

Well, took the Boker for a spin after a week of messing with a jnat edge...irritation and redness!! Worse shave in a looong time. Will run the blade on glass and restart. I think going from leather to sprayed leather must do something to make the blade less smooth for my skin.

Now that I have a decent jnat, I am going to finish on it before moving to the sprays....so the edge will be coti-jnat-sprays on balsa-sprays on leather.

Ken was also mentioning sprays on the jnat so....

 

[Seraphim]

You could probably use sprays directly on a piece if glass instead of mucking up your $$$ natural stone.

 

[Kentos]

You could probably use sprays directly on a piece if glass instead of mucking up your $$$ natural stone.

Ah, good idea...I just need to find some glass. Ideally I would love a 3/8th 3x8 piece.

 

[Kentos]

Looked at the Boker today under 20x loupe...would you know,
I think I saw a microbevel shining back at me. I hold my strop loosely, so I guess the nano grit poly, despite it's small size, still takes off enough metal to round the edge in matter of, what, 1 week of shaves? It's funny that the GD lasted longer tho. The bevel on the Boker is pretty tiny compared to the GD, so maybe that affected the longevity of the edge.

Tomorrow I will see if laps on a coti on water will bring the rounded edge back. If it does come back easily the added keeness of the edge maybe worth the short lived life of the edge stropping on sprays. Dropping down to .25
CBN on balsa brought back some sharpness, but I question the smoothness now...test shave tonight for the answer....maybe the thing will shave fine with a perpetual micro bevel?

 

[Brownbear]

..........I rehoned the Argus, a Torrey 136 and my beloved Joseph Elliot three owl razors with a full dilucot on my Veinette to an HHT 3, then stropped 40-60 times on fabric, then 40-60 times on the CBN hanging strop and then 100 times on my home made shell strop. This one I sanded today with 600 grit sandpaper in a quarter sheet sander, creating a luscious suede like surface. That strop is lovely to use as well, which explains the over the top amount of stropping.

So, I now have three razors stropped to HHT 4 on the hanging CBN strop. Nice coticule edges pushed to sharpness beyond my personal limits on the stone. (Not saying I won’t eventually get there with stone alone, just saying I can’t right now).......

This week will be test time, should be fun.

So here is an update on the setup described previously. I have this idea that we don’t think enough about bevel angle so here is a summary of the three razors treated as above, and a fourth that will enter my humble story later.

Size Initial angle w 1 tape w 2 tape
Argus 13/16 15.6 16.4 17.2
Elliot 11/16 17 17.9
Torrey 11/16 14.9 15.9
Wosty 11/16 14.5 15.5 16.5

I gave all three of the razors a fair trial with multiple shaves. The Argus and Elliott were very sharp and dreadfully harsh. The Argus particularly, had an affinity for human flesh. I could not shave with it without multiple weepers and cuts, I snagged my lower lip one day and gave myself my worst cut ever, it bled for 45 minutes. It was clearly very sharp but the polar opposite of a mellow forgiving coticule edge. The Elliot was similar but slightly less aggressive. But it gave me weepers like crazy and left my skin feeling flayed. The Torrey, oddly, gave quite nice and smooth shave with only a hint of harshness, and I got several shaves out of it that were quite nice.

So what am I to think? Well, I was speculating that the CBN would give a less harsh shave on edges with a larger final bevel angle. That is not what I found, the Torrey, with an angle of 16 degrees with one layer of tape, was the most mellow of the three, and the Argus, with an angle of 16 ½ degrees was horrible. Hmmm…. Maybe it is more than just the angle, maybe the steel comes into play here and 60 laps on a hanging strop with CBN is too much for some steels and OK for others. The Elliot, which has that nice soft feeling sliver steel, might have done better with only 20 strops on the CBN. And maybe the Argus just doesn’t need anything beyond a nice sharp coticule edge. I took it back to a La Veinette edge on water alone and lo and behold it gave me smooth and forgiving shaves.

All in all this left me feeling that maybe CBN is better for knives than razors, at least for those of us who favor coticule edges. I believe I could sharpen a knife on this stuff so sharp I could slice ripe tomatoes thin enough to read the New York Times through them, but this test left me doubting that CBN edges are skin friendly. (reminder here, I have very tough whiskers and very tender skin so YMMV). But…..I really like this CBN stuff and I enjoy stropping on this buttery hanging strop impregnated with the CBN. The feel is luscious and it just feels like it is really doing a good job. So, still pondering posts by guys I respect about using tape and putting on secondary bevels and unwilling at this point to give up the idea that the very sharp edge produced by CBN could make a less acute angle sharp enough to do a great job while standing up to the battering it gets from thousands of tough whiskers I decided to try this:

I touched up the Argus with 200 strokes on water on my Verte (ah, old friend, I am sorry I forsook you for that upstart Veinette, yes, I remember that silky rasping sensation and wonderful edge you produce) to an HHT of 3, then canvas and shell to a final HHT of 3+. This would be a lovely shave. Then I subjected the blade to 20 laps on my hanging CBN strop, intended to push the sharpness up but not round the bevel. At that stage my edge was at HHT 4, a noticeable step up in sharpness. Then I added a second layer of tape for a final bevel angle of 17.2 degrees and did 20 very light laps on the Verte, at a pressure less than the weight of the blade. Interestingly the first ten or so felt like the blade was trying to take a slice out of the stone, then it settled in and just glided over the stone. My intent was to put a very tiny secondary bevel on top of the already scary sharp first one and leave it with an unmistakable coticule edge so as to avoid flaying my skin from my face. I was left with an edge that was an HHT 4 from either end.

I enjoyed this so much I grabbed a sharp Wostenholm XXL and did essentially the same thing. Ended up HHT 4.5 held from one end and 4 from the other.

That was Friday. Saturday I shaved with the Argus and this morning I shaved with the Wosty. The result was the same for both; I got wonderfully smooth, weeper-free shaves from both blades that were a step up in sharpness from my usual coticule-only edge but had all the forgiving smoothness a coticule can give. I can gage the sharpness of a straight by whether and how easily I can go ATG on my upper lip. Normally I don’t try as it takes a lot of concentration and isn’t very gratifying. My normal shave will leave me with a detectable grain if I run my tongue up my upper lip. With an open comb DE or a SE injector or GEM 1912 I can get my upper lip perfectly smooth ATG but only after multiple buffing strokes that leave it burning a bit. With these edges I was able to get my upper lip baby smooth ATG without undue razor burn and the shave lasted until bedtime.

So, it appears that this technique combines the best properties of the coticule and CBN and gives me a boost in sharpness with no downside. Now will follow trials to see if taking it back to the coticule without the second taping does the same thing and trying different numbers of CBN strokes and such. I’ve already tested whether putting a secondary bevel on top of my normal dilucot edge improved the edge and it didn’t, but I’ll have to test that again to be sure the above results aren’t just purely a function of the secondary bevel. The increase in HHT after CBN stopping suggests they aren’t. And I am particularly interested to see if the less acute, but still very sharp, secondary bevel stands up better to the battering of my whiskers over the long haul; so this coming week I’ll shave with the Argus exclusively until it no longer feel sharp. Generally I get a week’s worth of shaves before an edge needs a touch up. As sharp as this edge is I’d be happy with that if it stays sharp most of the week, but I’m hoping it might hold up longer. And so it goes….the tweaking continues.

 

[Kentos]

That's interesting that the secondary bevel on the coti AFTER the CBN yields a sharper smoother edge, and the same edge without the CBN isn't as good...any theories on why?

 

[Brownbear]

None at all, but it is 14 hours later and my upper lip is still smooth. Has something to do with the serrations on the edge i suppose but it would take an electron microscope to visualize it. I do get the feeling when shaving right off the CBN that I am using an incredibly fine toothed saw.

I'm not entirely certain what sharpness is. But to the extent that it is at least partly the radius of the meeting of the two bevel flats the small size if the CBN must allow a smaller radius curve. By doing only a few laps on the coticule you may be preserving most of the finer radius while altering some aspect of it for the better.

What if sharpness is occuring in the profile of the cross section perpendicular to the axis of the blade and smoothness is a characteristic of the line of the edge along the blade? Maybe the less uniform particle sizes in natural slurries create a more random edge pattern along the length of the blade.

What would we get if the CBN suspension contained a larger range of particle sizes, say for example, a mix from a micron or so down to a few nanometers? Might that create a smaller radius on average along the blade with a less uniform line in plan view?

 

[Kentos]

None at all, but it is 14 hours later and my upper lip is still smooth. Has something to do with the serrations on the edge i suppose but it would take an electron microscope to visualize it. I do get the feeling when shaving right off the CBN that I am using an incredibly fine toothed saw.

I'm not entirely certain what sharpness is. But to the extent that it is at least partly the radius of the meeting of the two bevel flats the small size if the CBN must allow a smaller radius curve. By doing only a few laps on the coticule you may be preserving most of the finer radius while altering some aspect of it for the better.

What if sharpness is occuring in the profile of the cross section perpendicular to the axis of the blade and smoothness is a characteristic of the line of the edge along the blade? Maybe the less uniform particle sizes in natural slurries creates a more random edge pattern along the length of the blade.

What would we get if the CBN suspension contained a larger range of particle sizes, say for example, a mix from a micron or so down to a few nanometers? Might that create a smaller radius on average along the blade with a less uniform line in plan view?

In essence create an artificial natural stone slurry? Depending on how the CBN breaks down it might be able to mimic the slurry off a jnat. From what i understand the jnat slurry breaks down into smaller and smaller bits giving that sharp smooth edge.

 

[Brownbear]

Yes, that's what I'm thinking, but with a smaller median size and with the faster action that the abrasive provides. Who knows? We are beyond sound theory here I think. I don't even know why coticules produce such great edges much less what is happening at the scale of some of the finer CBN and diamond products. But maybe we have moved into too tightly engineered territory and it is time to think of playing with size mixes to look for synergies amongst the different particles that I assume the natural stone produce.

 

[Woodash]

In essence create an artificial natural stone slurry? Depending on how the CBN breaks down it might be able to mimic the slurry off a jnat. From what i understand the jnat slurry breaks down into smaller and smaller bits giving that sharp smooth edge.

I'm guessing that the CBN wouldn't break down much, if at all, and I don't think it would behave anything like the Jnat slurry which is comprised of very different kinds of particles.

 

[Kentos]

I'm guessing that the CBN wouldn't break down much, if at all, and I don't think it would behave anything like the Jnat slurry which is comprised of very different kinds of particles.

I think you are probably right. Once I get consistent edges off the jnat I'll spray different grits of CBN on glass or something and give it a whirl.

 

[Seraphim]

FWIW, I just had a shave with a razor that came off 1um lapping film that I had sprayed with my 0.5um diamond/chromox mix. I don't know if the synth slurry added anything, but it was a quite comfortable shave.

None of my usual pasted stropping either, just right off the film.

Visibly, I see no difference in the edge finish with synth slurry or without, so I'm not sure if it is actually adding anything to the process, or if it is simply a 1um film edge. Which is what I'm suspecting you'd experience with nano grit on a JNat. The JNat is obviously larger grit than nano, so adding the nano may simply leave you with the sane thing as just the JNat in the first place. But that is purely conjecture on my part for the sake of discussion.

 

[Woodash]

FWIW, I just had a shave with a razor that came off 1um lapping film that I had sprayed with my 0.5um diamond/chromox mix. I don't know if the synth slurry added anything, but it was a quite comfortable shave.

None of my usual pasted stropping either, just right off the film.

Visibly, I see no difference in the edge finish with synth slurry or without, so I'm not sure if it is actually adding anything to the process, or if it is simply a 1um film edge. Which is what I'm suspecting you'd experience with nano grit on a JNat. The JNat is obviously larger grit than nano, so adding the nano may simply leave you with the sane thing as just the JNat in the first place. But that is purely conjecture on my part for the sake of discussion.

Yes - I agree, but I think it's more than just particle size. The Jnat particles are basically clay (platy) minerals that slide past each other - kind of like a deck of cards vs. grains of beach sand (differences in size notwithstanding). When wet, the clays 'slide' more and mostly polish without cutting as much. When drier (paste-like), there is less 'lube' and slightly more cutting, but nowhere near a faceted, harder particle. My take...

 

[ken123]

Well two areas of exploration might be useful here.

1) Adding a SMALL amount of very fine CBN on the Jnat OR coticule surface or C12k for a hybrid preparation. For the total purist I'd suggest deionized water to further reduce particle agglomeration Well, perhaps a total purist wouldn't be doing these sorts of things I'd also suggest at this stage of the game to avoid more porous stones (e.g. various suita). This is a wet technique and seems to breakdown the natural slurry more rapidly, leaving a natural stone finish. VERY interesting effect when used on very abrasion resistant steels, but also very interesting generally. I've also used CBN at grits in the same range as the stone on synthetics, but not yet on J-Nats.

2) Taking a bit of slurry from the J-Nat or coticule and adding it to a CBN prep on some balsa. This is a dry technique, performed after the slurry has dried on the balsa. Apply wet and allow to dry to be more clear. The restriction of using stones with pores (su) is lifted as this avoids stone contamination possibilities. Have not tried this yet on a coticule.

I've experimented with both natural and synthetic slurries as pure slurries on Balsa with success, so combining them with an over spray on the strop with some CBN might be quite interesting. Either adding stone slurry to CBN slurry or vica versa. By and large the stone slurries harvested from both synthetic and natural stones tend to be finer than using the stones directly. I've done this with various Nakayamas, Hakka, Yaginoshima, 30k Shapton Pro, 10k Choceras, to name but a few of a larger collection (actually all the Choceras, some superstones, the Shaptons, other naturals, etc) I've used these techniques on both balsa and paper. For coarser stones, harvesting with diamond plates is just fine. Paper over glass gives the effect of a harder stone, so for instance a Hakka prep gives the effect of a harder stone, but with the fineness of grit of the Hakka, losing the softness of the Hakka. Similarly a Nakayama Asagi on balsa or even leather gives a softer effect than the original stone. And so on.

For the natural stone slurries, consider slurries generated using either a knife or razor and/or tomonagura to be finer than slurries generated using a diamond lapping plate. On these dry preparations which include the metal swarf I have not noticed rust formation to date.

I know all of you will come up with even more interesting concoctions and look forward to hearing about it.

---
Ken

 

[Brownbear]

I'm guessing that the CBN wouldn't break down much, if at all, and I don't think it would behave anything like the Jnat slurry which is comprised of very different kinds of particles.

That's the point. It doesn't break down and it is fast so perhaps the face friendly properties of natural stones could be created along with the ultra sharp properties of the CBN by mixing particle sizes in the way that natural stones likely (but where is the evidence?) behave when a slurry is used. I don't know anything about JNATs, but they are meant to be smooth. I really don't know why naturals are smoother and, coticules at least and perhaps JNATs as well, less likely to cut skin. But I suspect it is because the edge is not uniform at the microscopic scale in the way synthetics are. Don't really know but it would be easy to mix a range of CBN and diamond ultra particles and give it a try.

"Visibly, I see no difference in the edge finish with synth slurry or without, so I'm not sure if it is actually adding anything to the process,"

But the features we are talking about are not going to be seen with light microscopy. Maybe the larger scaled features of the edge, but not the radius of the bevel junction or those smaller features you can see on the SEM photographs from Verhoveven's paper.

I haven't seen any data to confirm one way or another that JNAT slurry breaks down or that coticule slurry does or does not contain whole garnets. This is all empirical and we are speculating, which is fine. So an empirical test to see if mixing a slurry of different sizes of uber fine synthetic particles would give an equally sharp but more face friendly edge would be cool. I think Bart is on to something when he talks about plastic flow when stropping. And I expect at the scale of these little particles there is something happening that isn't just big particle effect / 1000.

 

[Seraphim]

I really don't know why naturals are smoother and, coticules at least and perhaps JNATs as well, less likely to cut skin.

My suspicion is that they simply are not as high a grit as the uber synthetics. The drum I've been beating as of late is that less is often more: by backing off the super ultra high grit stuff, to simply very high grit (1um hits it for me), leaves a less "perfect" looking edge under the scope, but the shave performance is way, way better. And my experience is of course on synthetics, so I don't think it's a synth vs natural thing, but rather a matter of getting over seeing how far we can go with the crazy grits (my name is Seraphim, and I'm a microscope addict...), and finding out what hits the shave sweet spot.

For me, 3um isn't very pleasant to shave with, 0.5 is good, but can easily tend to the harsh side if you're not careful, 1um is plenty sharp for whisker removal, but is much much kinder to your (mine, anyhow) skin

 

[ken123]

There is a good amount of data that Japanese natural slurries do refine themselves or break down and that the PSD (particle size distribution) is broad. There is an electron micrograph 'floatiing around' somewhere that shows a Nakayama Kiita slurry showing the flakes of various sizes in the slurry for instance. Often the shapes are flake like (of course there is a wide variety of shapes among naturals) and break up into smaller flakes. Particles like CBN don't tend to reduce so readily at all. I couldn't say anything authoritatively regarding coticules. The action of these more brittle flakes would be expected to be much different than the more spherical shapes of CBN and mono and poly diamond, so the resultant action would be expected to be very different too. These shapes also make it very hard to determine particle sizes, making it very difficult to rate grit sizes on naturals in a meaningful way.

Just using a slurry will show edge refinement with further use of the slurry which can be detected both by feel and changes in the scratch pattern. You do see this in Japanese natural slurries, but not synthetic slurries.

What I'm suggesting for someone who prefers a natural stone type edge is modifying the natural stone slurry by increasing the rate of breakdown of the natural stone particles with a bit of CBN 'doping'. This results in a natural stone finish, not a CBN finish.

I haven't tried a 'blend' of various grits of CBN or diamond or even both, but instinctively it wouldn't be my preference, expecting to just get a fine finish mixed in with coarse scratches, resulting in a finish most like the coarsest grits in the mix. If anyone tries this I would be curious to know what they thought of it.

---
Ken

 

[Kentos]

It was just a thought that mixing the sprays would result in a edge with a non-uniform pattern. Comfort of edge doesn't seem to always accompany a mirror finish, although instinctively i would think the more smooth the edge the more comfortable the shave. So what makes that hazy edged coti or jnat edge so nice? Maybe an edge polished by random sized particles? Thus the idea of having a slurry with different sizes of grit..maybe .25, .1, .05 and .025...just a random idea.