How to grind certain blade styles - questions inside

cbr900son

cbr900son

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Mar 3, 2011
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So I was looking at some Karambits and was suprised to find out it actually has some interesting history and not just for mall rats or tati-cool fans. Also while looking at some knives I got to wondering on a few grinds and how they go about doing them and thought Id ask yall

1) how do they grind extreme curves like these

Kerambit_knife_and_sheath.JPG


2) How do makers make a sweeping plunge that is this extreme? It almost looks as if they are using a disk grinder.

brendsnewbreed.jpg
 
2) How do makers make a sweeping plunge that is this extreme? It almost looks as if they are using a disk grinder.

+1

I have been wondering how to do that myself the last few days,i just cannot figure it out on my grinders. Can one of the experts please explain?
 
Yeah it baffles me. I can do a slight sweep by running the belt over the edge of the grinder but that throws me off.
 
it can be done on a flat platen but you have to hold your tongue right :D. i did a similar grind on a fixed blade similar to the one you posted above but i made it into a convex grind.
 
One way to do the sweeping plunge is to set a "normal" plunge ahead of where the sweeping part will be, then blend it back by hand. There is a tutorial around here somewhere, and an example in Lorien's PIF thread.
 
james terrio said:
One way to do the sweeping plunge is to set a "normal" plunge ahead of where the sweeping part will be, then blend it back by hand. There is a tutorial around here somewhere, and an example in Lorien's PIF thread.
Click to expand...
That makes sense. Any idea on the karmbit grind?
 
I'd like to know also. I tried to make a version of the al mar warrior and the top portion of the blade, which has a similar curve, turned out real bad. It now sits in a drawer unfinished. I bet that a lot of hand work is the answer.
 
cbr900son said:
That makes sense. Any idea on the karambit grind?
Click to expand...

I would guess the originals were forged as close to shape as possible. If I were asked to make one by stock-removal, I would cut the profile normally and grind the bevels with a small wheel or by hand, and even it out by draw-filing. I imagine it could be done on the corner/edge of a flat platen, but would take a bit of care and patience.
 
very carefully !!!! would be my first answer :D

but seriously I think you use the contact wheel take your plunge at an angle and only use the very edge of the wheel then as you progress the length of the blade you straighten it out and use the full depth of the wheel..

of course this isn't an educated guess, I'm just grasping at straws.. :)

hopefully Ray will post a pic after he masters the grind real quick, with a full tutorial of course :D
 
A crowned contact wheel works. I ground a couple of sharp inside curves some years back with the crowned drive wheel on my 1x30, it worked pretty good. You can also do it fairly well using the edge of the belt, you just have to be extra careful about gouges that way.

The best way might be to build up a crown on a contact wheel with electrical tape. Or, if you are flat grinding it would be pretty easy to make a platten with a radius from side to side.
 
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