Hard edges to sharpen

golok

golok

Joined
Oct 20, 2000
Messages
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I was just wondering if there are some knife edges that are difficult to sharpen. I have experience this on numerous occasions. I don't know whether it's because I am not good at sharpening knives of certain types.

I don't seem to have problems with most knives but there are a few that stump me. I was wondering if it was because of the kind of edge on the knife.

Perhaps someone could tell me of similar experiences.
 
a chisel edge gives me fits,I still haven't figured it out.
emerson commander is the one I speak of.
anyone got any tips.
 
The sharpening FAQ here addresses sharpening chisel ground blades if you haven't already checcked it out. The whole FAQ is invaluable for a novice or an expert.
 
For me, any knife hardened over 60 Rc is a problem. I've had three that were tough, not impossible.

Well, one was darn near impossible. My wife has a Kershaw Boa made from CPM440V. As it happens sometimes with very hard steels, the bevel had a ding that was actually 'concoidal fracture.' That's the rounded chips you find, like in the bottom of a chipped beer bottle.

I started to polish them out with the Edge-Pro's 180 grit. Yikes, the knife hardly left any slag on the stone!

I will say one thing about very hard steel, when you polish them with the polishing tapes, they gleam like a chrome bumper! Her Boa is still gleaming.

Same deal with my new Companion, an ATS-34 hardened to 60 Rc, which I think is too much for that steel. It was not uniform on the rear right bevel. It just took careful work. It too gleams when polished.
 
Tourist, the Boa is quite a sharpening challenge. I worked mine for at least an hour and a half trying to raise a burr on both sides. The end result was great though, it hasn't required anything but minor touch-ups for two years now.
 
I've found that diamond stones work well for me with any steel, but I am too much of a 'tard when it comes to sharpening recurves. I have to pay extra attention to the angles is the main problem, I can't just zone out and sharpen like I like to.
 
The difficulty in sharpening a knife can usually be attributed to several causes; the steel hardness, the edge geometry, and the kind of sharpening device you use.

1. Seel hardness. For steel with hardness less than 60 RC or at 60 RC, I usually use Indian Stone fine grit. Works like wonder. Occasionally stropping the edge with a sharpening steel will make it razor sharp. When the edge is really blunt, I use diamond stone to create a 'new' secondary bevel, then I use Indian stone to remove the coarse serration.
For above 60 RC, I use the same method, but diamond stone is used more than the Indian. Indian is used to remover the coarse serration.

2. V and concave edge are easy to sharpen. I don't think you'll have problem with them. A thick Moran edge is sometimes problematic when sharpened. Sometimes, you'll have to remove a large amount of steel, and Diamond stone works best for this purpose. When the edge is a bit thinner, again Indian is used.

3. Ceramic rod, Sharpmaker, sharpening steel, are usually used to 'maintain' the sharp edge. To create new bevel or to create a new edge, I'd recommend low grit (very coarse) diamond rod or stone.

Those are from my experiences, some might agree with me or not, but I can make a blunt edge shave my arm hair in a matter of minute without scratching the blade (only the secondary bevel).

Good luck !
 
I have a Kabar 110 that I tried to sharpen on my 204, and it became duller..I think that it's Sooo dull that it's going to take hours, or a belt sander :confused: --Joe
 
I just zone out when I sharpen... 5 minutes turns into 45minutes without thinking about it. Can get some damn sharp knives like that though... lots of light pressure and letting the abrasive do it's work.

sandpaper and ceramics are all I use. My strop gets hit 1/2 way through the ceramics to help with the wire... if I use the strop.

my spydie kiwi, calypso jr, and military(ce) all slice AND pushcut through yellow earplugs without squishing.
 
>> pushcut through yellow earplugs without squishing.

What a great test!

I test the 'bite' with a horse hair paint brush. It should be able to split hairs at the tips. If you have to push too hard the bristles will move out of the way and the blade won't grab. All hunting, skinning, and most pocket knifes should be able to pass that test.

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Hardest to sharpen? Hmmmm, probably convex/moran edges where you don't know exactly how they were made. You really have to duplicate the method or set a new edge.

Steve
 
Sando: picked up the earplug test here on BFC last year. I don't have a steady flow of the good ones though we have 40db ones at work(yellow/pink striped, more rubbery than standard yellows). Can get the yellows cheap though at any hunting or shop supply place.

My hardest to sharpen is my toughest edge. spydie ss pe dragonfly. flat on the blade(12ish deg), 15ish inclusive, and then a midpoint to soften the shoulders. 80-1500 paper on flats, strop, 1200 at 15, 1500 at mid. Takes a sweet edge with an agressive bite on it, while still shaving when fresh. Mine went off a month ago for a new sheath, but I hadn't touched the edge since july 31st, and it still sliced easy. That was a result of a year playing on that edge.
 
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