A wire edge that cuts?

Noctis3880

Noctis3880

Joined
Jul 22, 2009
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Okay, I've been using my Para2 in CTS-20CP for a while now with the factory edge(mostly to see how long it lasts), and I've noticed that it has a bit of a wire edge clinging on for dear life that hasn't been removed from cutting cardboard, corn, and wood. Thing is, it seems to cut "better" than my polished edges on my BM 581 in M390 and R.J. Martin Overkill in S110V, at least on corn. It could just be my imagination, though I notice I don't shove the blade in as hard as the other two, and my arm isn't sore the next day.

As well, my Para2 slices paper easier than my Overkill or 581.

I figure it might just be that a rough "toothy" edge ultimately cuts better than my mirror polished stuff, but it just boggles my mind that the wire edge can cut at all. Though perhaps "wire" isn't accurate. Since it doesn't roll to the other side, it just looks like someone finished grinding the left side and either didn't bother to remove the burr, or simply couldn't.

Farid had mentioned that S125V HAD to be mirror finished or it would be stuck with the edge rolled to one side. I just assumed that the high volume of vanadium carbides makes removing the burr tricky at best.

Still, I'm wondering if I should go for a coarse grit finish. My theory is that finer finishes has the "apex" where the two sides of the edges meet at a single point. Whereas a coarse finish forms a burr because one side overlaps the other at the apex, ultimately meaning that it would take more to wear away enough steel to round off that apex.

I still have yet to actually compare my mirror polished Para2 in S90V, but I'm thinking my theory could explain why the coarse edge slices better. I'm just not sure how to go about putting a coarse edge without as much of a burr on such steels. I'm pretty sure 9% vanadium steels would laugh at a strop. Though I was wondering if jumping grits(from something like 320 grit to a 3 micron belt) would do it.
 
what system are you using to sharpen? i've never had a wire edge which would slice paper very well but thats jsut me. id remove that wire edge before you cut anything to eat for sure. you dont want it inside you.
 
A wire edge is hard and non moveable, and as your seeing it will stick with the edge through EDC use. It's one of many reasons I don't advocate running a edge through wood to de-burr because it is rare it will do anything.

Your knife cuts because the burr is sharp, its likely as thin if not thinner than the apex of the edge and just as hard or harder than surrounding metal. You may feel this edge is a performer but its performing Due to a factor you will not reliably be able to reproduce. I think the main reason it might be performing better is because of blade geometry, once you get past the bevel the sharpness of the edge plays less and less into cutting performance.
 
Its amazing how durable a wire edge can be sometimes, one of the reasons I don't believe using fine compound on a relatively lower grit edge will really clean it up. If dragging it across some hard maple won't budge it, compound on leather is only going to shine it up nice.

IME I've never had a wire edge that cut as well as a nice clean edge, all other things being equal. As far as creating a quality coarse edge, you're on the right track with the larger grit compound, but I'd say you have to go even larger than 3 micron. I don't have a chart handy, but I think that's about 1000 grit. Something on the order of 30 micron equates to 400 grit? Using a stropping particle in the range of your grinding grit will reliably produce the best quality coarse edge. Frankly I'm surprised this isn't a far more common practice. Properly done you'll wind up with a coarse edge that's burr free as well.

If this is really why that particular knife is outperforming others in your collection only you can say. I can't tolerate a wire edge even if they do frequently perform quite well. As knifenut says, its a one-off.

HH
 
just a thought, when i was on KF, in the kitchen section, the folks here organized a "sharpening olympics" iirc, the knife sharpened by murray carter was the sharpest in use, it felt sharper, but once it touched the leather belt, the whole edge failed, the knife was actually cutting on the wire edge.

you can ask dave martell about this, he was the judge. he's hanging there these days.
 
Well, I put a 320 grit(I think...) finish on my Overkill with better results, though I also thinned out the edge a little. However, it still seems to slice paper easily. My Para2 in CTS-20CP was mirror polished, and while it doesn't seem to feel as sharp while cutting corn, it still cuts through newspaper like a hot knife through butter, so I'm not sure what the issue is with that.
 
Noctis3880 said:
Well, I put a 320 grit(I think...) finish on my Overkill with better results, though I also thinned out the edge a little. However, it still seems to slice paper easily. My Para2 in CTS-20CP was mirror polished, and while it doesn't seem to feel as sharp while cutting corn, it still cuts through newspaper like a hot knife through butter, so I'm not sure what the issue is with that.
Click to expand...

Some edge grinds perform specific tasks better than others. Could be the fibrous nature of the corn calls for a more open grind that can separate the material as it cuts. For cutting newspaper, the finer grind tends to work better - as long as you're using a strict push-cut. I find that for push cutting my edges need to be above 220 to work well, with the best results kicking in from 400 grit and up. 320 grit that's finished well, will shave arm hair and push cut newspaper though likely not do so well across the grain. It all comes down to what you're using it for. This is why I have stropping grits from 120 up to .5 micron.

HH
 
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