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Thread: The Unicorn method
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2nd August 2020, 07:36 PM #16
Well based on what I've seen I think it's worth getting a buffing wheel and having a play around with the technique to see what works. I must admit that I feel pretty lucky to be on the receiving end of info like this. Thanks David and Derek!
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2nd August 2020, 07:52 PM #17SENIOR MEMBER
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I'm very interested. In particular it would mean throwing all the theory eg of Brent Beach etc out the window. It would also cohere with why the Paul Sellers method of vigorous stropping on soft leather works.
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2nd August 2020, 08:19 PM #18
Brent Beach (RIP) was an academic in regard to sharpening. His method certainly left a sharp edge, but was so out-of-touch with someone actually building furniture. Very, very inefficient, and only suited to a rank beginner.
The method of Paul Sellers is not the same as the Unicorn at all. Sellers promotes a rounded bevel, not a rounded edge. He uses green compound to polish but this is because he jumps to this from a Extra Fine (1200 grit) diamond stone. His bevels are really no different from the traditional. The downside to his rounded bevel face is that the blade can only be used from one side; it cannot ride on the bevel, such as when cutting bevel down. Not recommended. Again, aimed at beginners.
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
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2nd August 2020, 09:16 PM #19SENIOR MEMBER
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Thanks Derek
I will admit to hoovering up Brent Beach's entire website but as someone who regularly has to absorb expert opinions critically it seemed long on a sort of intuitive theory of things being significant (eg the significance of a wear bevel), absent from a broader theoretical understanding of what was at work - or experience.
Although I think that passing Paul Sellers off as promoting a rounded bevel as opposed to edge perhaps undersells him (excuse the pun).
From my watching/reading - I know he has mentioned the convex rounded bevel is very pleasing aesthetically but he has not promoted that (so far as I can tell) that is an advantage in sharpness in and of itself or leads to a better cut or edge retention . And when you think about it, that would be nonsense (ie that the bevel itself - including the part nowhere near the edge - contributes to the sharpness of the edge). There are a few subtleties I've noticed in things he says in passing without emphasis - for example why he thinks thinner, old-fashioned plane irons are an advantage (the lesser the size, the easier the sharpening). I was thinking through it once and realised it was not just the effort (more material) but also ensuring that you hit the edge with various passes. It seems very unlikely something so substantial would have been left unsaid.
(I should emphasise I stand to be corrected here).
He does say that the stropping on leather is vital to his method - and again my re-watching shows it's deliberate he uses the inward-facing, soft leather - it seems inevitable when you look at what is being done it must be intended on producing an edge that is either slightly rounded or that it doesn't matter. Of course when you're talking about theoretical particle-level physics - what is rounded and what is straight?
It could not, it seems, be possible to assume anyone with half a brain would not realise that pushing a bevel through a relatively soft medium with effort will not round an edge microscopically at the very edge. You can see the leather deforming in his videos and he promotes high pressure. That will inevitably mean the material is springing up against the edge.
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2nd August 2020, 09:38 PM #20
It crossed my mind when I saw this for the first time, that the Unicorn is not too far removed from the lenticular/fuller profile given to heavy combat swords in the medieval age.
Until 22, I was into that kind of thing. Chainmail, sword making, bashing on each other....
Here are some of the common profiles.
While a sword is no chisel, its purpose was not to dissimilar...!!
They were no clowns when it came to sword making. It was a matter of life and death....
external-content.duckduckgo.com.png
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2nd August 2020, 10:20 PM #21SENIOR MEMBER
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Thanks woodPixel
The thing about theory is that it only takes us a narrow distance, it seems, when the object of the theory is how to cut wood fibres. Unless you can accurately or reliably simulate what happens when wood particles meet metal particles of different configurations formed by different sharpening methods through sufficiently uniform sharpening techniques then we have to be informed by experience not theory.
That doesn't mean we should abandon any sound understanding of what is going on microscopically at broad levels... but it really seems theory can only inform things we might want to try out and not what we should accept.
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2nd August 2020, 11:27 PM #22GOLD MEMBER
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Hi, guys - yes, not succinct. There's something wrong with my brain, but if I pretended it's getting worse as I get older, it would be ignoring that it was bad when I was younger. But juggling a bunch of details as I get older is getting more difficult, and I'm not that old (Mid 40s).
As for the name, I shared what I call "the roll" with Bill and Wiley on wood central as a way to deal with substandard chisels or really difficult wood. That was a while ago. Bill finally did it - I don't know if wiley ever did. Bill never tries anything that I suggest unless someone else tries it first and reports that it's successful. Wiley is too polite to tell me he didn't try it. The roll is just creating this same profile with a hard fine slow stone (so as not to round over too much).
When I posed the buffer as an option, Winston Chang tried it, showed pictures of success (Without changing angles anywhere, just rounding over the edges of soft hardware store chisels), and Bill started calling it "the weaver bevel". I don't like that. I'm sure someone else is doing it at present, and many have done it before.
I sat on the roll mostly unless someone said they were having edge issues because I get tired of hearing about how guru X or Y says an edge is only truly sharp if it's the intersection of two planes (maybe, but people will complete most of the planes and not the edge as a matter of laziness - they will complete the parts they see, and then that edge will be transient until the part that's fragile leaves. If the intersection is blunt enough to stop most of that damage (generally about 34 degrees), then it feels blunt, crushes pine and shoots parts off of harder woods. I used a chisel like this to mortise planes for a while. The chips from mortising a plane go all the way across the shop all over the place.
The roll is wonderfully useful, though. The buffer just does it better - faffing off and on with the buffer was to evade other ways of getting the same edge. loaded strops are OK, but they can become contaminated and it's more physical work to use one. Same with hard fine stones. Sooner or later something is sitting on the to and you can feel a small "click" when you roll a bevel. And the buffer completes the job that most people won't complete, it's gentle but quick, it doesn't draw a burr like a paper or leather or felt wheel, and if used only sparingly on the very tip, it doesn't spoil the nice cutting of the edge.
But there's almost zero chance that I won't hear about person X, Y and Z who have all been doing this all along.
No trouble with planes so far, by the way - I thought the edges wouldn't be strong enough for middle work, but sized a rough sawn indian rosewood blank with a stanley 5 and O1 iron (my own make of iron), and saw fewer lines of damage from the silica in it. And there's plenty of silica in the blank. There's less room for error in not overdoing the buffing with a plane iron, though. Just enough to smooth the edge and remove the burr and no more. Chisels, it doesn't seem to matter exactly what shape you end up with - short and blunt rounding, a little more gradual, etc.
An article will be coming to wood central at some point. I've written it, it's long, and Ellis is going to edit it (the site owner there - he's a book and magazine editor, as well as having done actual quality woodworking for pay) - he's doing some editing for more important things, so there may be some delay. Some of the other folks trying this may write an article for print magazines (or what's left of them), but I don't like writing short articles that don't describe details or show some proof that something actually works. To me, without proof, people make a half-arsed effort at trying something, then write it off as not working because 10 minutes of trials don't fare well against something they've done 2000 times. This is one thing that's worth pursuing.
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2nd August 2020, 11:35 PM #23GOLD MEMBER
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It's a little harder getting the amount of "do or not do" right on planes due to clearance, but the shavings at really fine thinness are more uniform (better sharpness makes both thinner shavings and shavings that are more uniform at a similar thickness when shavings get really thin - washita stones will take a thin shaving, same with 8k waterstones, but the uniformity of the shavings becomes more like a fine lattice and not like a nice uniform layer. The buffed edge really makes a nice uniform shaving.
Trying to get a picture of reflectivity is difficult, though. I have no manual camera, only phone, and they're designed to eliminate glare. I tried the partial manual settings on my phone after planing cherry...but the catch here is that I planed it against the grain, a harder test.
You can see the individual LEDs from the overhead light on this. In person, you can see these LEDs with perfect clarity - the phone camera just won't quite tolerate capturing the glare without constantly adjusting focus, though. Even on "manual".
https://i.imgur.com/ivsb5X8.jpg
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3rd August 2020, 12:36 AM #24GOLD MEMBER
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(the wood in the prior picture is unfinished).
As part of my article, I ran a test of my theory (more of a guess) that I could get a sorby chisel to match a V11 or japanese chisel. I couldn't quite. This chart of number of strikes to cut an inch of maple gives an idea of effort, but better performance reduces effort more than just the numbers, probably double as much from not having to reset bouncing chisels in cuts, etc.
The other surprise is that the regular unicorn method did not yield zero damage from V11, but it did greatly reduce it. The sorby chisel only got to "almost no damage", too, but as soft as it is, the improvement was excellent.
This method is two-fold. One is improving edge retention and ease of cutting on good chisels, but the other is getting mediocre chisels (like marples, robt. sorby, etc) that otherwise feel nice but are intolerable to use to match really good chisels well enough to avert spending where it's not wanted.
Here's the count of the strikes needed (I did note in yellow that it's possible in some scenarios to match performance with the soft sorby chisel if you're setting the "Good" ones up in certain ways).
https://i.imgur.com/eWH3gvQ.png
Here are the pictures of the edges:
first cell is freshly sharpened, and then the rest are edges after each test. The MK2 and japanese chisels showed no damage at all after "unicorn" profile and chopping maple.
Sorby (each picture cell is about 1.5 hundredths of an inch wide and 2 hundredths tall).
https://i.imgur.com/iQDXjsc.jpg
Ashley Iles:
https://i.imgur.com/NQv1T0z.jpg
PM V11:
https://i.imgur.com/wm9C67Y.jpg
Japanese:
https://i.imgur.com/hxGkIoe.jpg
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3rd August 2020, 02:02 AM #25
Brent certainly raised awareness about the wear bevel, and his investigations into how a blade wears were ground breaking. He and I used to correspond and swap notes. However, that does not change my comments above. His method of sharpening was fastidious, inefficient and would appeal to the academically-minded rather than the doer. It would not fit into the workshop of someone building furniture and wanting to get on with it.
Paul Sellers does not create a Unicorn bevel on his strop, regardless of how much give the leather has. We are not referring to an extra 5 degrees at the edge (which can result from a soft leather strop), but an extra 20- or more. This can be achieved by deliberately lifting the blade up as you make a stropping stroke, but only doing so for two or three strokes (to create a nano bevel), and Paul has never done that. I have been using his method on Western mortising chisels for some years, and understand what he does ... and does not do.
Paul would recommend thinner blades because they are easier to hone with his method. That is not a criticism, just an observation. Thicker blades require alternative methods as there is more steel to hone than make his method viable. So hollow grinding is my preference. Others prefer a secondary bevel.
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
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3rd August 2020, 02:03 AM #26Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
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3rd August 2020, 08:01 AM #27SENIOR MEMBER
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This is fascinating David. I have a stitched wheel I actually only use for restoration work (cleaning up things like old plane irons after rust removal following some sandpaper) and a couple of chisels at very acute angles around 20 degrees.
I might see if I can give your method a try and respond with some photos. So that it has maximum chance of assisting do you have any tips on hitting the preferred angle on the wheel? In your video I couldn't pick up any particular method. Was it just eyeballed, or was that after a bit of practice (ie should one not try that straight away?).
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3rd August 2020, 08:21 AM #28GOLD MEMBER
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There isn't really a method to it. for chisels, just introduce the bevel side of the chisel to the buffer at about 45 degrees to the point of contact, let the buff sort of form itself around the contact for about 5 seconds on a 1 inch chisel (maybe less on a narrower chisel) , move the chisel around a little bit so that the edge is evenly buffed (it's OK to buff the corners, i haven't noticed a detriment -I don't mean angle the chisel around to push the corners in, but if they get buffed a little bit while buffing the edge, that's fine).
(the reason there isn't a method is that as long as you get the buff to go over the edge, it doesn't seem to be that important for it to be doing something *exactly* a certain way.
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3rd August 2020, 09:55 AM #29SENIOR MEMBER
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3rd August 2020, 11:16 AM #30SENIOR MEMBER
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Thanks David
I'm working from home today so snuck an attempt in.
The chisel is a cheap vintage from ebay. I see a machinist for flattening hand plane soles and asked him to do a couple of chisels so the back is dead flat. It has been useless however because the angle is so acute (how it came). It visibly fractures if it even looks at wood. It is about 20 degrees.
I put it in the Veritas Mk II honing guide with the detente about halfway between 20 and 25 degrees, to get a 22-23 degree secondary (see picture).
(Edit: I should note that yes, the secondary shows a skew. It is because of a slight skew in the chisel grind of how I received.)
IMG_20200803_082510.jpg
IMG_20200803_093245.jpg
I then gave it a quick bit of go on the wheel with some Josco green crayon. The phone photo is terrible but you can see a bit of the wax back from the tip.
IMG_20200803_093607.jpg
I then cut a few slices until the phone went.
IMG_20200803_094747.jpg
The slicing was into a big offcut of Merbau post. It is a tough but not extreme piece of hard wood that lays around as a doorstop/shim/something heavy. I just did some paring slices with hand pressure. It went much better than expected as is immediately obvious, because it did actually slice instead of immediately fracturing and giving up.
But I grabbed another well-honed chisel sharpened with the Sellers method and it was noticeable better with much less cut resistance.
I suspect I did something wrong as I noticed what felt like a fairly extreme burr on the back after those few slices. I will re-watch your video again and have another go.
My wife is already making jokes about my "working from home" so may be tonight/tomorrow.
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