Something to try – a left/right differential edge

[wickededge]

I’ve been thinking about the way that scalpels are made with one side rough and the other polished and I’m wondering about finishing knives that way. I just tried it on a Victorinox 3″ paring knife. The results were interesting. The knife definitely prefers cutting in one direction over the other but is extremely aggressive on the side it prefers. I used 100# stones on the left (when in the vise) and then polished the right hand side up through 1000# and then used the 9 micron films. I continued alternating strokes all the way through, just keeping the 100# stone on my left the whole time. I’d love to hear other’s results and impressions if you get around to it.

-Clay

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Tactical Texture LLC, Frans

[Josh]

Interesting! I’ll have to give it a shot…

[dima]

Clay, were you cutting straight down or at an angle (kinda like sushi chefs do)?

[378pete]

wickededge wrote:

I’ve been thinking about the way that scalpels are made with one side rough and the other polished and I’m wondering about finishing knives that way. I just tried it on a Victorinox 3″ paring knife. The results were interesting. The knife definitely prefers cutting in one direction over the other but is extremely aggressive on the side it prefers. I used 100# stones on the left (when in the vise) and then polished the right hand side up through 1000# and then used the 9 micron films. I continued alternating strokes all the way through, just keeping the 100# stone on my left the whole time. I’d love to hear other’s results and impressions if you get around to it.

At what angle?

[wickededge]

dima wrote:

Clay, were you cutting straight down or at an angle (kinda like sushi chefs do)?

Good questions. I was trying all kinds of angles and found that as long as I was cutting down and to the right, the knife performed great, but not so much angling back to the left.

-Clay

[wickededge]

378pete – I sharpened it at 16 degrees per side.

-Clay

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378pete

[dima]

Interesting. I tried it today on 2 Henkels knives – chefs and pairing. Both were sharpened at 18 dps. One side 1000 grit, the other one is 100. No microbevels. No stropping either.

Results are some what mixed. It did reasonably well with chopping, using chef’s knife. But it felt a bit uncomfortable. Pure slicing was very nice, though. With pairing knife I had a whole lamb leg separating it to muscles. Definitely better than expected.

Now, while it was an interesting test, would I employ it on my regular kitchen knives? I’m using Takeshi Saji R2 knives in my kitchen (sharpened at 12 dps). The answer would be – no. They are more versatile as is, IMHO. But for some projects this idea has a potential.

[tcmeyer]

The scalpels I looked at were sharpened both sides at about 600 grit, then polished on one side only.  Maybe the 100 grit is too coarse.

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wickededge

[Tactical Texture LLC]

I kid you not, but this was going to be my FIRST experiment when my new setup comes.

I had heard in a few posts on another forum that Ken Onion recommended using Tormek honing past ONLY on the side of the blade that had the bur to get an amazing edge.  While he was running the paste on a leather wheel, he said the results would be the same doing it on the Worksharp w/Blade Grinding Attachment and stropping belt.  He claimed that it gave a ton of bite, while still refining the edge a bit.

The funny thing is that when I was thinking of this, I actually wondered if there would be a difference in the way it cut (much like a chisel grind).  Not because of the sharpness, but the difference in friction caused by one side vs. the other.

It looks like you are seeing in practice what I suspected.  I believe the difference should diminish fairly quickly as you bring the rough side closer in grit to the other, but then you would lose the bite.

I was going to try only going to 400 or 600 grit on one side, then a light hone with the tormek paste on a balsa strop (I suppose you could use leather, like you do with the toothy micro technique) and polish the other to see what that did, so if you get a chance to take it up a few grits, I would be more than interested to hear what you find out.

I think the with a little more experimenting this has the potential to be a great setup, we just need to find the right combination.  I think the key is that the rough side still has to be a refined toothy edge (ala the 200 grit micro + strop) in order to make this work.

[Mrniceknife]

I did something similar with a crk sekaiyo 6″ it needed some repair so I started with the 50/80 then stopped at 200.  I took the burr off the chisel edge with the 1k stone then stropped with .5 paste on leather.  It’s 19 degrees on one side and that’s it.  The edge is impressive.

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[dulledge]

Mrniceknife wrote:

It’s 19 degrees on one side and that’s it.

In other words you have 19 degrees inclusive. You made edge like straight razor edge (9.5 degrees per side). Of course it is impressive, but is it practical? And for how long will it last? I think that people here had different meaning and different idea. The idea was to try coarse on one side and polished on other side and use regular angles.

EDIT: This is specialized Japanese knife. I know nothing about Japanese knives. Please ignore my post above. Sorry…

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