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We have a massive amount of Edge Pro products so we figured it would be good to have a whole section on how to use the machine and what to use on it.
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Thinning a Knife

Sun Mar 09, 2014 3:32 pm

Another question from a very new sharpener: I'm using an Edge Pro to sharpen a Wusthof classic paring knife, which was completely dull when I started. After initially sharpening, I got to the point where the knife would easily slice newsprint and magazines, would shave hair on my arm, and would easily go through a tomato, which was progress. The problem is it doesn't do very well for the task for which I most commonly use it -- halfing or quartering apples. While it goes through the skin of the apple easily and does fine with making small slices of apple, it does not do well with a with halfing a whole apple. It starts sticking about a third of the way through.

My uneducated reaction was that this indicates the blade needs to be thinned. So I set the Edge Pro at around 10 degrees and used a course stone (Nubatama Bamboo 120) to remove some metal from behind the edge. Then, I refinished the edge itself at a higher angle using finer stones (stock 220, 400, 600, 1000, Shapton 4000). I can definitely notice a difference visually -- there is now a course bevel going slightly higher on the knife than previously (though the bevels still are not very wide). But it made no apparent difference in the performance.

Any suggestions for how to improve my results? Other than the knife being too thick behind the edge, is there anything else that would cause this "sticking" problem? If the cause is thickness, am I better off trying to thin freehand and go higher up the knife than I can get with the EdgePro?

Thanks in advance for any advice!

Re: Thinning a Knife

Sun Mar 09, 2014 4:45 pm

Thinning at 10 deg with maybe an 18 or 15 deg final edge should have worked wonders. How long did it take you to thin the knife? Even with a Bamboo 120, the stainless on the Wusthoff is difficult to abrade.

Re: Thinning a Knife

Sun Mar 09, 2014 5:07 pm

I didn't spend that long with the Bamboo 120 b/c I was afraid I'd take too much off. Maybe 15 minutes? Perhaps I just didn't do this long enough?

Re: Thinning a Knife

Sun Mar 09, 2014 6:43 pm

You need to almost complete a 10 deg bevel (doesn't need to apex perfectly) and then establish your cutting edge. If you can do that in 15 minutes without (or even with) diamonds I have a box of stainless to send you.

Re: Thinning a Knife

Mon Mar 10, 2014 10:35 am

Hi there, yes as my friend Mr. Swarfy indicates, the work you do at the 10 deg point will take some time, the actual sharpening process at the higher angle will be much quicker. I usually have a 5-6 deg spread between the Relief Angle and the sharpening angle so if I intend to sharpen a knife a 19 deg and I want to thin I will do that at 15 deg. I will go from my coarsest stone up to my finest and spend 30-45 minutes there. Then when I am satisfied that I have actually achieved my goal of reducing the width of the secondary bevel area I sharpen the knife at 19 deg starting with a 2k stone, sometimes even a 5k.

The key is to spend whatever time is necessary at the "reducing angle", don't rush that part of the process.

Peter
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