I am surprised

[Derek Cohen]

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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...

Jack, altering the quality of the steel is exactly what the unicorn profile is all about! David launched this method with the intention of turning chisels with too soft steel, which would dull rapidly, into something to compete with better quality steel. And in this he succeeded. There have been a great number of posts now on WoodCentral demonstrating this. My own post, above, found that the soft steel of Marples chisels, honed at 20 degrees, began to hold their edge - for the first time - after adding the unicorn profile.

Regards from Perth

Derek

[Timberwolf]

Jack, altering the quality of the steel is exactly what the unicorn profile is all about! David launched this method with the intention of turning chisels with too soft steel, which would dull rapidly, into something to compete with better quality steel. And in this he succeeded. There have been a great number of posts now on WoodCentral demonstrating this. My own post, above, found that the soft steel of Marples chisels, honed at 20 degrees, began to hold their edge - for the first time - after adding the unicorn profile.

Regards from Perth

Derek

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Derek, I had a new set of blue handled Marples { from Lowes } that had the "soft steel" problem several years ago because they were not hardened properly from the factory...They were no good to me the way they were, so being an old time machinist, I brought out the oxy-acetylene rig and I heat-treated them again. That improved their edge holding ability tremendously...the steel wasn't the problem,,,the tempering process was...If that can be done without heat treating,but keeping the same bevel angle and sharpness, I say go for it... I am all for learning new tricks....

[hbmcc]

Hear! Hear! Just in time!!

In a few weeks I go in for a new shoulder. I must have tools that allow less-than-25 lb pressure to sharpen. Neither PMV-11 nor Covington Japanese chisels encourage such a 'weenie' approach to complete the task of sharpening by traditional methods. I am feasting on the WoodCentral unicorn banter right now. Will pick a carpentry chisel and a good one to experiment on ... before the chop job.

BTW, stropped over green on top grain and the proof is in the blood and nail slices. .5 micron on steel plate is a hit n' miss finish. Currently, the last thing I do is strop. Jack! You are the Man! Even plain leather works.

[AHill]

Curious and honest question. How is this different from "dubbing an edge" when stropping? Wouldn't that cause the same kind of rounded edge that is accomplished by the buffing wheel? Or is the dubbed edge not as aggressive an angle as what occurs using the Unicorn Method?

[Derek Cohen]

Allan, there is an interesting fact and experiences that are emerging for me about manual stropping. For some years I have been careful to avoid dubbing and, instead of using a leather horse butt strop, as I did for many years, I turned to LV green compound scribbled on a piece of flat hardwood (I prefer not to use MDF as it becomes chalky under the top hard layer).

The recent photos published by David Weaver and Winston Chang on the unicorn profile using a powered soft buffer demonstrate how must effort is needed to create wear on steel. David did some tests to work out if it was reasonable to do this freehand on a flat strop. From memory, he needed about 50 strokes, which is what Paul Sellers requires when sharpening (moving from 1200 grit to the strop). And Sellers uses a lot of muscle here.

On the one hand, this says to me that dubbing an edge on the leather strop is unlikely to occur in one or two strokes, which I do to ensure the wire has been removed. And yet, there must be some form of a dubbing action since stropping on leather, which has some give, seems to achieve a fine edge faster than stropping on hard wood.

In any event, one is unlikely to create a unicorn profile on a strop. It can be done manually, but you need a more abrasive medium, such as a fine waterstone.

Regards from Perth

Derek

[cputnam]

Curious and honest question.  How is this different from "dubbing an edge" when stropping?  Wouldn't that cause the same kind of rounded edge that is accomplished by the buffing wheel?  Or is the dubbed edge not as aggressive an angle as what occurs using the Unicorn Method?

Not knowing what a dubbed edge looks like under the same scope as Winston is using means that I cannot speak to the dubbing question. Have you seen Winston's imaages of a Unicorn profile? As I interpret the image, the last couple of microns of edge get rounded such that they create an effectgive angle of 45° or so. That is what provides the durability. The diminutive size does nothing to impair the chisel's ability to be "sharp", to put pressure enough on a small enough area as to sever fibers.

David Weaver has scientific curiosity and wants to know why as well as what. I am content that the what works and will take other folks word for the why. Even I can freehand for 10 or so stroles on a 1200 grit DMT and while sticking it on the beffer needs to be done correctly, incorrect technique is not catastrophic because the next 10 strokes on the DMT removes the evidence and we start over.

[Timberwolf]

Not knowing what a dubbed edge looks like under the same scope as Winston is using means that I cannot speak to the dubbing question.  Have you seen Winston's imaages of a Unicorn profile?  As I interpret the image, the last couple of microns of edge get rounded such that they create an effectgive angle of 45° or so.  That is what provides the durability.  The diminutive size does nothing to impair the chisel's ability to be "sharp", to put pressure enough on a small enough area as to sever fibers.

David Weaver has scientific curiosity and wants to know why as well as what.  I am content that the what works and will take other folks word for the why.  Even I can freehand for 10 or so stroles on a 1200 grit DMT and while sticking it on the beffer needs to be done correctly, incorrect technique is not catastrophic because the next 10 strokes on the DMT removes the evidence and we start over.

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 I am content that the what works and will take other folks word for the why.

That's pretty much my feelings also...I don't have time or equipment to dedicate to the "why"..I am more interested in achieving the sharpest edge possible in the shortest amount of time, and how long it will keep that edge to my satisfaction. After all these years, I pretty much "know it when I see it"...and know what to do to correct the problem if one arises,,..Power stropping is a great time saver once the technique is mastered.

[Pedder]

isn't that what Tage Frid did to his chisel?

[Derek Cohen]

Pedder, as I recall, Tage used a belt sander to grind the primary bevel. I don't remember what he did after this .. if he did anything at all.

Regards from Perth

Derek

[Pedder]

I recall to have seen a movie wit a lot of green stuff.


Cheers
Pedder