Help Fixing a Bent Tip

B

BK14

Joined
Sep 13, 2016
Messages
448
Normally, I would just toss it in a vice and give it a go. But this knife is of pretty strong sentimental value to me, so I want to hopefully revive it with the least amount of damage possible. Upon his retirement, my dad gave me the knife he carried with him most of his Airforce career. It is a long discontinued Kershaw boot knife. It has spine serrations and a relatively fine tip, of which the last quarter inch or so is bent about a half centimeter or so at the tip. What’s the best way to straighten this enough to correctly sharpen? Thanks!
 
All you can do is bend it back. It may break, but the knife would have to be completely disassembled, annealed, bent, reheat treated, and reassembled to do it any other way. If it breaks, the tip can be reground.
 
Bill DeShivs said:
All you can do is bend it back. It may break, but the knife would have to be completely disassembled, annealed, bent, reheat treated, and reassembled to do it any other way. If it breaks, the tip can be reground.
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I think you’re right! Just gotta go for it.
 
It doesn't matter if you move it a little or a lot, when it reaches the breaking point-it breaks.
 
Some steels take more set the longer you hold them bent (less spring back), some don't. It's worth a try.
 
Bill DeShivs said:
It doesn't matter if you move it a little or a lot, when it reaches the breaking point-it breaks.
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Hi,
Well thats true :)
but how you avoid the breaking point?
You go little by little right?
Keep going until the blade/tip is straight and stays straight and then stop.
It takes some experience to avoid going too far.
 
A 0.5 centimeter deflection in the last 1/4" of the tip (0.635 centimeter) sounds pretty extremely bent to me, if it's described accurately in the OP. Plugging those numbers in geometrically, that's 38° of bend.

I think Bill is right; it may not matter how one goes about trying to fix it, as it may break anyway. If the bend is that extreme, the steel may already be damaged and weakened beyond fixing it back to a usable condition. But at that point, it basically doesn't matter anymore. If it's that weak, it'll need to be removed and the tip reground anyway. Even if it doesn't break now, the 'fix' may just be cosmetic, to a straightened tip with no strength, to break later, if/when it's used to poke or pry anything down the road.

One way to find out.


David
 
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Obsessed with Edges said:
A 0.5 centimeter deflection in the last 1/4" of the tip (0.635 centimeter) sounds pretty extremely bent to me, if it's described accurately in the OP. Plugging those numbers in geometrically, that's 38° of bend.

I think Bill is right; it may not matter how one goes about trying to fix it, as it may break anyway. If the bend is that extreme, the steel may already be damaged and weakened beyond fixing it back to a usable condition. But at that point, it basically doesn't matter anymore. If it's that weak, it'll need to be removed and the tip reground anyway. Even if it doesn't break now, the 'fix' may just be cosmetic, to a straightened tip with no strength, to break later, if/when it's used to poke or pry anything down the road.

One way to find out.


David
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Thanks for the insight, David. My numerical estimate may be a bit off but it is more dramatically bent than any I’ve had before. I’m kind of curious as to what he tried to pry with it!
 
I would suggest a flat anvil and hammer. It may break but others have already said that. The hammer will not over bend the steel if you even slightly careful. May take more than one strike to get it where you want it.
 
kwackster said:
Very gently in a vise between 3 carefully placed pieces of wood has worked many times for me.
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Lapedog said:
How would you place these three pieces of wood?
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You set them in a zig zag pattern, two on one side with the third on the opposite side positioned between them. By adjusting the spacing you can get an aggressive bend over a small area or a gentle one over a larger area and everything between.

I recently glued magnets to the back of three 3/4" half round oak dowels for this very purpose. You can see exactly where the bend is being applied and how much.
 
Sorry to bring back the dead, but I got a Western W 75 boot knife at a garage sale for $3. It's in pretty nice shape but the tip is slightly bent. I need to know how big a hammer and how hard to hit. Tap-tap with a four oz brassie, or give a moderate thud with a 3 pounder.
 
I had a bent tip on a Buck 317 and straightened by the method the guys use over in the Traditional Forum with a hammer on a metal plate. Dip it a little in boiling water, pull it out and tap it. It works. Good luck, DM
 
On a 3$ knife I wouldn't bother. Still, I'll give you the information. The hammer I used was a Plumb carpenter hammer @ 1.5 lbs..
The blow (being 8-10) was a wrist action only of about 6-8" lift and no arm push. Just wrist. Enough to drive a #6 finish nail but not enough to drive a 16d. DM
 
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