convex sharpen

blgoode

blgoode

Knifemaker / Craftsman / Service Provider
Joined
Oct 3, 2003
Messages
7,147
Well...I had my first go at it. THe tricky part of convex sharpening(to me) is I cant decide if there's a constant angle of the sandpaper or not? I used 320 grit paper first then went to 400 grit. I may go back and start over with 220 or something. After the 400 I tried to use my belt to strap with. Overall its ALOT better than before. I cut through a 6" dia. piece of tree quick. What can I do to get a better edge. My tools are limited to hand only.
 
With the grit of sandpaper you are using you really arnt removing much steel. If you want to really convex that sucker get some 220 or 150 to start with. What you have is great for sharpening, as you can tell, but not good for really shaping. I started with 150 and have gone up to 800 so far on a HI Katana that I fancy.

(BTW, I am planning on starting over at 150 because I have found some areas that arnt quite what I want them to be as far a convex goes. I have about 5 hours of elbow grease in it right now.)

You can do it with what you got, but it will take you more time and sandpaper.

You can polish the edge with the higher grit you have but if you do get the 150 and 220 grit stuff, you might like the 'rough' edge it leaves.
 
I do think the rough 220 edge cuts tomatoes like butter!!! I'll try it again starting at 150. What type of angle do I look for or do I just go by "FEEL"?
 
I just "feel" for it. Remember that the thinner it is the more likely it is that it will chip out for chopping.

Are you using a mousepad setup?

I have strips of mousepad glued to pieces of a yardstick, and then sandpaper glued to the strips of mousepad. I hold the sword in my lap on the floor and work the sandpaper that way. It also works well for khuks.
 
There is no constant angle, that's why it is convex instead of flat.;)

The angle is steeper the nearer the edge one gets.

If the sandpaper is on something soft, it will conform and produce a convex edge. If the sandpaper is on an unyielding surface, then the angle will have to be increasesed closer to the edge.

Don't worry about the very edge until most of the shaping is done, otherwise things might be more obtuse than planned. Doesn't take much metal removal to make the very edge more obtuse, but a lot has to be removed to thin it. The very edge will get some sanding even if you don't deliberately sand it, especially with a mousepad backing.

Mark the blade with a magic marker or change the direction of sanding, or polish with a finer grit ocasionally and you will be able to see were you are removing metal. After a while, you should get the "feel", but it's good to check once in a while with one of the above methods.

By hand, at least for me, a good intial goal is just to try and get rid of the parts of the bevel that are hollow, at least around the sweet spot.

Good luck.
 
Keep up the tips guys. I'm chewing through as many of the archived sanding/sharpening threads and tips as I can find, and any add'tl pearls you all through out are much appreciated. I'm gonna set up the mouse pad strop this week. I read Yvsa's musings , and planned on a strop(s), but wasn't sure about belt/block, etc. Have to confess to being intimidated by the convex grind, and full blade polishing is a new notion as well(Can anyone tell me what I might need to get out some scrathes on a D2 blade?). I think practicing on the old AC is a good idea before I go screwing up the WWII en route. You all are a treasure trove of info, glad I wandered in.
 
just made a mouse pad sanding block. I'll have another go at it tonight or this weekend........now on to the strapping. Use a leather belt?
 
all great info guys....:D Blgoode I also use an old leather belt.It comes in handy for now untill i can afford a real one. frank
 
Originally posted by Yahmanin
"Have to confess to being intimidated by the convex grind"


I was too, put it off but finally was convinced and tried it and I think it is actually easier than the other way. Certainly more durable it seems.
Click to expand...
 
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