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Sharpening 10/15

Thu Mar 27, 2014 2:23 pm

I have a Mac Pro that I use for practicing different techniques. I read a post I think from BDL that said this knife really shines when sharpened 10/15. Does this simply mean for a right handed person you sharpen the left side of the blade at 10 deg and the right side at 15 deg? Would this cause steering issues?

Re: Sharpening 10/15

Thu Mar 27, 2014 5:03 pm

I have no idea what he meant to be honest. However, some thoughts:

Most typically when referring to an asymmetrical grind, the total usually counts to 100.....60/40 or 70/30 or 80/20 or 90/10 or..... It's not normally listed as angles per side.

My best guess is he meant a compound bevel. 10 degree primary, 15 degree micro. So the knife is sharpened at 10 degrees and the raised to 15 degrees on each side and stropped a few times to put on that 15 degree micro bevel.

Re: Sharpening 10/15

Thu Mar 27, 2014 5:05 pm

Thanks for the insight. I'll play around and see what happens

Re: Sharpening 10/15

Thu Mar 27, 2014 5:41 pm

10* on one side, 15* on the other would be very close to a 70/30 grind and depending variables could cause steering.

Re: Sharpening 10/15

Thu Mar 27, 2014 8:09 pm

Sharpening angle, degrees per side that is, has nothing to do with asymmetry.

No matter what angle you sharpen at, you can put the center line of the edge any where you want depending on how much grinding you do. If I sharpen at 10 degrees on the right side of a gyuto and remove metal at the edge until there is no back bevel, then the asymmetry is at something like 0/100. The edge is as far left as I can make it. Whether I do that at 10 degrees or 20 degrees, the edge ends up in the same location and the asymmetry percentage (let's call it percentage, k? :o ) is the same no matter what angle I used.

Now, same knife, if I sharpen the left side at 15 degrees for just a few strokes and move the edge in only slightly, the asymmetry might be at 20/80. Keep going on the left side at 15 degrees until there is no bevel on the right side and the edge bevel asymmetry is at 100/0. You could stop at any point, using any angle and have edge asymmetry (or symmetry at 50/50) anywhere from 0/100 to 100/0.

Hope that makes sense.

Also, please keep in mind I'm only talking about edge asymmetry and not entire knife grind asymmetry. Obviously sharpening at the edge can not change a knife's asymmetrical grind overall. :)

Re: Sharpening 10/15

Thu Mar 27, 2014 9:15 pm

Makes perfect sense Adam, thanks for the lesson.

Re: Sharpening 10/15

Thu Mar 27, 2014 11:27 pm

See post nr 11 by BDL:
http://www.cheftalk.com/t/68970/mac-kni ... sides/0_20

The 10 degree bevel is the relief bevel, behind the very edge.

Re: Sharpening 10/15

Thu Mar 27, 2014 11:51 pm

Excellent info guys. I definitely learned something from this. Thanks benuser for locating that post.
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