How to sharpen curved, thick blade?

J

JanS

Joined
Sep 19, 2011
Messages
4
Hi Guys! I'm new to this forum and a beginning knife maker but a longtime outdoors knife user. I know there are a number of "how to sharpen knives" posts on here but I thought I'd tap your expertise specificaly on this one:

I have a Kershaw Outcast bush knife/machette that I bought for a kayak/camping trip to Miconesia a couple of years ago. It is made of D2 steel and the blade is a quarter inch thick at the spine and narrows to maybe an eight before the ground edge. When I got it new it was unbelievably sharp for the thickness of the blade, and kept its edge through the trip eventhough it was in contact with salt water a lot. You could open an unhusked coconut with it in one or two blows...

Over the past 2 years it got dull with use and I don't seem to have a good way to bring the original edge back. I am used to using Arkansas oil stones but I also tried various commercial knife sharpeners. The problem seems to be increased by both the blade thickness and its curvature which makes it hard (at least for me) to use a flat stone with any effectiveness on parts of the blade.

Any suggestions on how to do this, in fact how to put a super sharp edge on other curved blades, will be very appreciated.

Thanks!
 
D2 can be tricky to sharpen on a stone as it is a very high hardness steel. I modifyed my outcast to a clip point blade style and sharpened the top edge and it was a tough messy job even w/ the 2x36 belt grinder I was using. A belt grinder will be your best bet that I can think of, or a chainsaw file, a set rough/fine diamond stones/rods and a lot of time.
 
where are you located? fill out your profile and see if there is a knifemaker near you. if so, they would probably be happy to help you with a belt sander.
 
thanks nathan :D. they can be next to impossible to sharpen by hand and even take a while on a belt sander. the last one i did was so hard i could not even put a nice satin finish on the blade even with a new belt.
 
Thanks guys for the info - looks like D2 steel is the sharpening material from hell. With my limited knowledge, I never even heard about it until I bought this knife. I actually have a belt sander, so would be interested to try it myself - what sequence of belt grits you recommend for this job (knife is dull but not damaged)? On the other hand, if I don't get anywhere - Richard J. - are you still interested in potentially giving it a try? I have a couple of other, non-D2 knives i could send you for sharpening along with this one? The D2 issue aside, I really like the knife for jungle-type work. My wife and I do a lot of adventure travel and I've had a chance to test many knives. This one is very compact, packable and effective....I guess until you need to sharpen it! Tribalmagnum05 - cool idea to make it a drop-point, if I get through just the sharpening I'm gonna do the same!

I started in knife making recently because through my business working with commercial fishermen, I have access to swordfish bills (or "swords") from their catches, and since the stuff seems to be regarded as rather rare as knife handle material, I've done a few fillet knives so far that came out pretty well (no problems honing those blades!). Any of you guys interested in (aged, semi-stabilized but not formed) swordfish bill material for knife scales to give a try?

Thanks again and let me know the belt grids...
 
three words wicked edge sharpner. pretty spendy, but it works each and every time. no experience needed.
 
jans, i had a member send me his outcast to sharpen after he gave up trying on his belt sander. it can even take me a while since i have my sander set to run slow. if you use a 1x sander you can end up with a washboard edge if you are not careful.

a 2x 72 would be the best sander to use. i would start out with at least an 80 grit to take the edge down thin enough to start the convex edge and work your way up to 400 grit if you want to go that fine for a chopper edge. i quit at 320 on the edge which is the same grit i put the satin finish on with. i finish off with the slotted paper wheel which takes the place of a strop and will polish up the edge.

rmbonham, he is wanting to convex his outcast and that kind of sharpener would not work. the paper wheels work much faster and will put whatever angle you want on a knife in no time.

jans, i would not send a knife to someone who you do not know ^^^^^. only deal with members of bladeforums and not some unknown person. thanks esav for taking care of ^^^^^^^ some people never learn or read the rules :rolleyes:
 
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Thanks Richard J.: Got your points and appreciate your grit info - will give it a try in the next few days and let all know how it turns out. Thanks again - much good advice!
 
Sorry Richard J. - just joined today an did not send any emails. But your info is appreciated !!
 
ok. send me an email with your number and i'll give you a ring and a few more tips. it will save us some typing :D
 
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