Convex Zero "Appleseed" Edge

[jefnvk]

Can anyone tell me about this? I picked up a CKRT First Strike for $10 the other day, figuring it was a good price. But then I find out it has this goofy edge.

Any info? Can it be sharpened the same way as a regular blade? Is tehre any special trick to using it for cutting (seems less sharp than other knives)?

 

[ecos]

there are three ways to grind, concave(hollow ground), flat, or convex (appleseed) concave is rarely used on edge bevels because it would weaken the edge too much, flat ground is the most common by far and is a good edge, convex was pretty rare til a few years ago when it started catching on as a trend. convex edge leaves more mass behind the edge resulting in a stronger edge (less chipping) but if done right can be extremely sharp. in my opinion a well done convex grind is superior. i make all my knives with a convex edge, it will pop hair off your arm like its not even there. if you follow the cutting competitions all the blades winning either are full convex grinds or convex edges. the main drawback is they can be hard to sharpen and it takes practice. also many people goof them up and round the edge off too much resulting in a dull blade(this may be the case of yours since you said it feels dull)
you can always contact a local knifemaker to see if they are willing to put a proper edge on it. if it has a good edge to start with it would be much easier to sharpen.
here is a photo of convex grinds and a comparision

http://home.nycap.rr.com/sosak/convex.htm

 

[ghostrider07]

Harbor Freight has the 1X30" belt sanders. I bought mine on sale for $25, watch for the sales. It's the cheapest way to put a convex edge on a knife, using slack-belt sharpening, on the unsupported part of the belt. You can practice on lawnmower blades and old machetes, and when you get a 220 grit belt mostly worn out, it's time to start on your knives.

 

[hso]

Years ago Mike Stewart at Blackjack Knives told me the best way to sharpen a convex grind without a belt grinder was to tack a piece of dense foam onto a 2X4 and then attach grinder belt to the contraption. This allows the belt to compress into the foam and creating the slack belt equivalent of a stone.

 

[jefnvk]

OK, thanks for the replies.

I'll probably try the foam/sandpaper thing. If not, there is a belt sander around here somewhere. THe knife is extremely dull, I can put pressure on it and slide it along my finger without som much as a scratch. If that doesn't work, I still got a cool looking $10 display knife.

 

[hso]

You could always send it back to CRKT if you bought it NIB and it was dull.

 

[JJE]

I mostly hang out at Bladeforums and plenty of people complained about the CRKT FS being dull as a butter knife out of the box. Even if CRKT didn't have any experience making convex edges, you'd think they would have figured out that they weren't coming out sharp.

 

[jefnvk]

I've noticed that as well, JJE, in lookinmg for info on this edge.

Got an email off to CRKT to see if they'll sharpen it, and if not, I'll give the sandpaper a try.

 

[jefnvk]

CRKT said toough cookies, you are on your own. So I took some 220 and 400 wetdry paper, and managed to put a good edge on it. Good enough to cut paper clean and shave hair on your hand, so it is pretty good.

However, I doubt that I'll ever buy a CRKT knife again.