Finally took the convex plunge

J

John K

Joined
Feb 22, 2005
Messages
175
I purchased my first HI this last winter-an M43 by Sher. It came with a pretty sharp edge so I didn't see any reason to do much with it. It went on several Scout campouts and chopped firewood and dropped several poplars that were 3"-6" in diameter that we used for lashing projects. It didn't skip a beat.

However, I knew that I would have to do some sort of edge work on this knife eventually. As helpful as the information on the Cantina is, it is also a little intimidating-I've never sharpened a knife to shave hair off my arm in my life! I don't have belt sander, and frankly, I'm a little too cheap to buy one-that same money could buy more khuks.

After digesting all of the information and advice on how to sharpen a khuk, I tried to make a hand sharpener to create a convex edge. I glued foam pipe insulation around a wood dowel. Around this I wrapped oiled sandpaper and began to work of an old AC khuk given to me as a present years ago. I quickly found out that the foam had too much give-it produce WAY TOO convex an edge.

I next took a clue from Yvsa-I glued a piece of leather around some more dowel and again wrapped oiled sandpaper around it. BINGO! The leather had just the right amount of give to produce a slender convex edge. Working through a couple of finer grades of sandpaper and finally red rouge rubbed directly into the leather gave me an edge I have never produced before. It still won't shave my arm, but it goes through paper like it isn't there.

I just took the new edge out to my backyard and chopped 6" into a piece of 5 year aged oak firewood-no chips on the edge and it still went through a piece of paper with little hesitation. A few passes with the chakma and it went back into the sheath ready to attack on the next campout.

As I'm still new to this type of work, any suggestions to improve this technique would be greatly appreciated!

john k
 
John K said:
I don't have belt sander, and frankly, I'm a little too cheap to buy one-that same money could buy more khuks.
Click to expand...

True, true...but consider this: an expensive belt sander is not required. I use the $100 Craftsman special from Sears. Plenty of others get by with the $30 Harbor Freight cheapie. For the cost of a khuk you can have a serviceable sander with plenty of belts to keep it company.

It's not that the end product will be any sharper than if you do it by hand; the advantage is in the time saved. It takes me less than five minutes in most cases to go from completely dull to shaving. When I factor in what my time is worth, the sander paid for itself in the first few days and the belts remain free. ;)

But, back to the topic at hand, I learned the basics of it with sandpaper on mousepad strips. The trick to getting very sharp for me was understanding the burr. Make sure the entire edge is burred, flip, get a new burr, flip, make one or two very light passes to grind off the burr, go to the next grit. Aim for being able to shave (roughly) at 400-600 grit. You can go as high as you want but back when I was doing it by hand, I rarely went beyond #1000 and #800 was probably enough. (In comparison, I go to #1200 on the belts.) Stropping afterwards will make it frighteningly sharp.

It took me a while to figure it out. My first couple tries actually dulled it further so you're doing better than me already. :)
 
I use a Delta I got on sale for something like $69 at Lowe's hardware...it works wonderfully.

I use the Delta for the initial reprofiling and convexing blades not already done, then after that only strop back to sharp.

Sounds like you figured out the hardest part...shaving will come with practice.

.
 
John?

Not only did you get some good instruction on sharpening from what's-his-name, but here is a magnificent example of rationalization by a contender for the Rationalization Semi-finals of the NorthWest League of the U.S.

It's not that the end product will be any sharper than if you do it by hand; the advantage is in the time saved. It takes me less than five minutes in most cases to go from completely dull to shaving. When I factor in what my time is worth, the sander paid for itself in the first few days and the belts remain free.
Click to expand...

He's a natural.

Read the safety thread. Practice rationalization in a "buddy" system, with appropriate safeguards until you are ready to enter amateur competitions in your area. Register and join the RRA* and help support legislation sustaining rationalization activities in your community.



*Rationalizing Rogues of America
 
I decided that I had to learn to do a convex edge.I started with my 21' GS. I cut postage stamp size pieces of sandpaper. I began with 220 grit,and using one finger to apply pressure started sanding lengthwise down the blade.

I've been doing that for a while now,and still no burr! Am I doing something wrong,or is it really that time consuming? I'm determined to learn to do it by hand,but it's been sorta frustrating!
 
RRA?! Do they have a support group for the wives?
Click to expand...

For spouses actually, and not so much a support group as a reviewing board to ascertain whether entrants are of sufficient skill and style to pass to the next level of rationalization ranking.

Actual spouses represent the rationalizers' equivalent of "combat," and as such, are treated with great respect and not given access to training or practice sessions.

Be well and safe.
 
stilgar said:
I cut postage stamp size pieces of sandpaper. I began with 220 grit,and using one finger to apply pressure started sanding lengthwise down the blade.

I've been doing that for a while now,and still no burr! Am I doing something wrong,or is it really that time consuming?
Click to expand...

Stilgar you need to review the directions and do it properly as indeed you are doing it wrong.:(
There's no way that you will ever get a convex edge with a fingertip and a postage stamp size piece of sandpaper.
 
You must log in or register to reply here.
Back
Top