Where are you with the unicorn sharpening method?

[Jim Koepke]

For those interested, this article came out a few weeks ago and fits in with the thread.
https://www.popularwoodworking.com/t...ening-meathod/

Interesting comment in the article:

several members have been developing and refining a sharpening technique that David Weaver, the originator, has since nicknamed “Unicorning"

David isn't the originator and my understanding is David said one of the reasons for the Unicorn name is so it wouldn't be called the "Weaver Trick."

If you look in Fine Woodworking (#39) from 1983 you will find it was an old method before many of us were born:

Sharpening to a Polished Edge.jpg

In the article Charles Riordan explains his preference for the hard felt wheel being due to the softer buffing wheel rounding the edge. With a hard wheel the secondary bevel is more flat and can be touched up on a strop before regrinding.

What was old is new again…

jtk

[Charles Guest]

Carving is a large part of my business and I know many quality carvers. We do not use buffers for our tools. We want a precision edge because we ride the tools on the bevels and on the backs. When someone talks about buffing a carving tool, they're probably not much of a carver.

Sculptors are somewhat different. They are not so precision oriented and many do work from a buffed edge.

Thanks for the laugh.

Here's a fellow who uses a buffer (the German Koch machine). Skip to around the 36:30 mark in the video.

https://www.youtube.com/watch?v=qls5oB76F2w

Here's his portfolio:

https://grabovetskiy.com/portfolio/

Looks pretty precise and lifelike to me, if not Grinling Gibbons level world class carving.

[Rafael Herrera]

I believe the real contribution made was the determination that an edge treated with this method will have a more durable edge. The discovery that an inexpensive chisel or plane iron will perform as well as or even outperform a fancy alloy steel. I don't think claiming to have discovered that a rotating abrasive wheel can be used to sharpen steel is even something anyone can make.

[Charles Guest]

Don't doubt it for a moment.

[Curt Putnam]

If one is so inclined:

Koch Sharpening System. Not sure about its current availability.

https://www.woodcraft.com/products/k...arpener-ht2000

From the late Nora Hall's website:

The Koch Sharpening System includes: 2 wheels and 1 paste. The two wheels or disks are manufactured using selected natural fibre and a specially developed process developed for the wheels. This has been patented. One wheel will be used for flat tools, and the second wheel for curved tools. For very wide tools, mount two wheels side-by-side.

During the sharpening action, both disks turn in a direction away from the body. The prescribed rotating direction is marked on each disk with an arrow. Experience shows that the best rotating speed is around 2000 rpm. The Sears Craftsman 6 Grinder (item # 21154) is recommended. Higher speeds lead to a reduction in quality of the cutting edge and are not recommended. There is almost no chance of burning the tool. With new or very worn tools, it is sometimes necessary to pre-grind on a grinding wheel or belt.

First, apply the sharpening paste by pressing it on to the running sharpening disk. The film of paste should be thin but evenly spread on the disk surface. For new disks, it is recommended that you apply sharpening paste more heavily until the surface is impregnated and ready for normal use. Generally, one application of sharpening paste is sufficient for each sharpening cycle.

"...So how does a 'thermal reactive' sharpener work? The Koch folks tell me the secret lies in the natural-fiber wheels and sharpening paste. Apply the paste to the wheel, then the tool to the wheel, and the wheel quickly heats to 240 degrees Fahrenheit (115 degrees Celsius). At this temperature the paste liquifies. A few seconds later, the tool is sharp and surprisingly cool. While I don't understand all the physics behind the process, I do know that it works.
"...With the Koch sharpener, I found I could get a mirror-like, razor-sharp edge in just seconds. And I noticed that I never had to remove burrs from the backs of my carving tools, the burrs were automatically removed when sharpening the bevel. This saved me a tremendous amount of time, especially when sharpening small veiners."

Tested by Harley Refsal, WOOD magazine carving consultant

After watching a number of the videos that turned up on a search, I've come to the conclusion that the system will preform well for those with the skill to hold aprecise angle at the wheel but not so well for with less skill or experience. Frim what I can see from the knide sharpening video, the bevel angle is entirely hand maintained. As we know, a difference of 2 degrees makes a huge difference. I know from my attempts to hand hold a constant angle over a powered leather strop that I need mechanical assistance. I'm also thinking that determining the angle is easier on a flat belt than on a circular wheel.

With all that said, I cheerfully admit that my assessment may be erroneous and/or that I missed someething critical. I'd appreciate a correction of my thinking if warranted. Regardless, thank you for posting the information about the Koch System.

[Charles Guest]

After watching a number of the videos that turned up on a search, I've come to the conclusion that the system will preform well for those with the skill to hold aprecise angle at the wheel but not so well for with less skill or experience. Frim what I can see from the knide sharpening video, the bevel angle is entirely hand maintained. As we know, a difference of 2 degrees makes a huge difference. I know from my attempts to hand hold a constant angle over a powered leather strop that I need mechanical assistance. I'm also thinking that determining the angle is easier on a flat belt than on a circular wheel.

With all that said, I cheerfully admit that my assessment may be erroneous and/or that I missed someething critical. I'd appreciate a correction of my thinking if warranted. Regardless, thank you for posting the information about the Koch System.

A beautiful description of woodworking, generally.

[John C Cox]

I look at it as a fairly efficient way to improve the edge stability when using jigged sharpening methods.

Free hand sharpening benefits from the small amount of natural monkey motion in the human body. It produces slight rounding in both the bevel and back, which increases edge life tremendously, unless you aren't good at it, and you end up chasing angles higher and making big roundy-bevels and humped backs which won't register worth a darned.

I tried the Unicorn thing on several quality vintage and modern mid-price chisels and all of them benefitted from a much longer edge stability. It didn't make them sharper than I can get them, what it did is made them far more resistant to chipping out/rolling edges. It didn't help the remaining Aldi or Harbor Freight chisels I had laying around... They are still trash and I binned the ones that I hadn't already jettisoned.

[steven c newman]

Hmmm..really?
Cedar Tray, rough cut handle.JPG