I am surprised

[camp10]

Does the speed of the grinder make a difference? Could I get a cotton wheel and chuck it in my 3.4K RPM bench grinder?

[Timberwolf]

I am surprised by the lack of discussion here about the so-called Unicorn method which has been well researched by David Weaver and posted on WoodCentral.  His results have been confirmed by other leading lights - including Derek Cohen.

In short, the method as described (if I have it correctly) is:

* - set primary bevel to around 20°
* - hone a few strokes worth of secondary bevel a few degrees steeper.
* - power buff with a cotton wheel loaded with compound

When applied to el cheapo chisels one gets and edge as good and as durable as premium chisels in a matter of seconds.

I strongly suggest it is worth your while to read all the posts on the subject.

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Power stropping has been around for 50yrs that I know of because that's how long I have been experimenting with it...using muslin, felt, leather copper and a host of other materials..They all work, but technique is the key to success...each one can perform differently...The softer materials can "remove" and edge just as fast as it can sharpen one if not used correctly..muslin buffs are great if used with a "light touch"...letting shaft speed do the work...The faster the wheel speed, the more dense the wheel "feels"....once power stropping is mastered, I doubt anyone would choose to spend so much time sharpening any other way..It's cheap, fast and efficient..."touching up" an edge just takes seconds......

Here's a shot of a little buffer I made many years ago for sharpening the wood carving tools I make...I have sharpened hundreds of small tools with it..I have muslin, felt and leather wheels for it and it does an incredible job at little cost...one of the handiest and most used sharpening machines I have ever made......

[AHill]

Allan, Seller’s method is not the same thing. The aspect that makes it appear similar is that his bevel face is rounded. However the leading edge of the bevel is not. And that is the important feature of the unicorn profile.

Similarly, if you buff edges on leather or felt wheels, unless you are deliberately lifting the chisel to raise the buffing angle to around 45 degrees, then what you are doing is just buffing at the angle of the face or the bevel. That is also not going to create a unicorn edge .... sharp certainly, but not unicorn.

Regards from Perth

Derek

I trust your knowledge better than mine, but David himself refers to his method as similar to the Sellers method.

https://www.youtube.com/watch?v=kH3deOUmCPg

And Sellers claims it's one single continuous camber:
https://www.youtube.com/embed/a6ykVzL2VA...ransparent

[Derek Cohen]

Allan, David only refers to the similarity in the rounded bevel face, and not in the shape of the edge of the bevel. This would be reinforced by Sellers calling it a continuous camber. Again, it is not the camber along the face to the bevel edge that is relevant; it is the treatment of the bevel edge, per se.

Regards from Perth

Derek

[Timberwolf]

Does the speed of the grinder make a difference?  Could I get a cotton wheel and chuck it in my 3.4K RPM bench grinder?

.....................
Depends on the wheel diameter and how tightly sewn the wheel is..The faster the RPM, the "more dense" the muslim wheel will seem...A four inch diameter wheel at 3450RPM will work fine if tightly sewn..That's the reason for close stitching the wheels..softer wheel are much more prone to "rounding over".....They used to sell cloth wheels hardened with shellac to stiffen them but I have never tried one..I do use "pleated" wheels that are 6" diameter for general buffing of larger tools...the cloth in those wheels that I have, seem to have been "stiffened" with something like starch, but not sure what material it actually is.,,At 3450 they perform well when 6" dia.

[Timberwolf]

I trust your knowledge better than mine, but David himself refers to his method as similar to the Sellers method.

https://www.youtube.com/watch?v=kH3deOUmCPg

And Sellers claims it's one single continuous camber:
https://www.youtube.com/embed/a6ykVzL2VA...ransparent

.......................
Check this out, Allen.....talk about "splitting hairs"......


https://www.youtube.com/watch?v=lManT10rt6g&t=311s

[cputnam]

Does the speed of the grinder make a difference?  Could I get a cotton wheel and chuck it in my 3.4K RPM bench grinder?

So far, that I know of, this approach has been tested with a full speed 6" grinder (what I have also), 8" half speed grinders and even a 4" wheel chucked in a hand drill. All work. Again, IMO, the full speed stuff needs a lighter and shorter duration touch than do the units with a slower surface speed.

The nice thing is that success is almost instant. Absent gross mishandling, anybody can do it. The proof is that I can.

What I did was to spend $10 for a sewn cotton wheel and stuck it on my el cheapo 6" full speed grinder. I am now in the process of reconfiguring to use this as my regular setup. Just eliminating all the fuss with honing guides will pay enormous benefits.

There is a difference in emphasis from what Jack has been advocating for years. I encourage everyone to read the relevant threads at WoodCentral

[Timberwolf]

So far, that I know of, this approach has been tested with a full speed 6" grinder (what I have also), 8" half speed grinders and even a 4" wheel chucked in a hand drill.  All work.  Again, IMO, the full speed stuff needs a lighter and shorter duration touch than do the units with a slower surface speed.  

The nice thing is that success is almost instant.  Absent gross mishandling, anybody can do it.  The proof is that I can.

What I did was to spend $10 for a sewn cotton wheel and stuck it on my el cheapo 6" full speed grinder.  I am now in the process of reconfiguring to use this as my regular setup.  Just eliminating all the fuss with honing guides will pay enormous benefits.

There is a difference in emphasis from what Jack has been advocating for years.  I encourage everyone to read the relevant threads at WoodCentral

...............................
Just eliminating all the fuss with honing guides will pay enormous benefits.

And the time you save sharpening can be used for working wood....just don't "overthink it". anybody can do it...use your bench grinder or lathe....A  really hair-popping edge will only last a few minutes but can be restored in seconds on a wheel......or a leather belt...I am glad more woodworkers are using them..

[Derek Cohen]

...............................
A  really hair-popping edge will only last a few minutes but can be restored in seconds on a wheel......or a leather belt...I am glad more woodworkers are using them..

Jack, the aim of the Unicorn edge is not to get "hair popping", per se .... I agree with you that a regular buffing gets sharp but may not not last long. The aim of the unicorn type of buffing is to achieve longevity at the edge. This is different from your experience of stropping.

Regards from Perth

Derek

[Timberwolf]

Jack, the aim of the Unicorn edge is not to get "hair popping", per se .... I agree with you that a regular buffing gets sharp but may not not last long. The aim of the unicorn type of buffing is to achieve longevity at the edge. This is different from your experience of stropping.

Regards from Perth

Derek

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Derek, I have always stropped to get the sharpest edge possible and I still don't think I have ever achieved it.

..I think a really sharp edge is extremely important in carving wood...and I don't like "settling" for less than as sharp as I can get it..how long the edge will stay "sharp" is determined by bevel angle and the quality of the steel..I can't alter the quality of the steel {except by heat treating } but I can easily change the bevel angle...Maybe I don't quite grasp the concept of the "unicorn method", because it seems to me that "rounding and polishing" the edge to strengthen it is what is being done in that process...and "rounding" is something I try to avoid...

I think I should go back and watch the video again...Maybe I will "get it" next time...