Straightening a slightly bent knife blade?

verbatim

verbatim

Joined
Oct 23, 2023
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3
I am not an expert on knives. I just want to straighten this blade.

I am told that some some blade are more "pliable" (not sure if that's correct terminology) than others. I am told that some blades can be manipulated, while others will easily snap.

Somehow this blade got bent and is hard to open when closed.

Can anyone offer any advice about how much wiggle room I might have to attempt to fix this problem?



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All you can do is gently bend it in the other direction. Slightly over-bend it-until it's straight.
Be very careful in case the blade does break. Make sure you have your hands in a position that they won't be injured, and safety glasses are a good idea.
Put the blade in a vise up to where the bend starts and bend it.
You may be able to hammer it straight, but that will mar the blade.
Good luck- I imagine you will be successful.
 
A knife like this will be able to tolerate some light hammering?

Before finding this forum, I did put the blade in a vise and gently used a pair of pliers to try to counter-bend it at the arc of the bend.
 
Does the bend in the blade impact it's ability to close?

I personally wouldn't touch it. Use it how it is.
 
If the blade was bent. Didn't snap. The steel is on the soft side.

Three points of contact in a bench vise. C clamp and a flat surface with a couple of contact points like drill bit shanks.

Hydraulic press. Arbor press...
 
> Does the bend in the blade impact it's ability to close?

Ever so slightly. But the bigger problem is when trying to open it when closed. As you can see from the pics, there is no fingernail notch, so when closed, it can sometimes be quite difficult to open. As I have been able to do a very small amount of straightening, it is slightly easier to open, but could really use a bit more straightening.

As I don't know anything about knives, my beginners level research indicated that some knife metal is more flexible or pliable than others.
 
verbatim said:
> Does the bend in the blade impact it's ability to close?

Ever so slightly. But the bigger problem is when trying to open it when closed. As you can see from the pics, there is no fingernail notch, so when closed, it can sometimes be quite difficult to open. As I have been able to do a very small amount of straightening, it is slightly easier to open, but could really use a bit more straightening.

As I don't know anything about knives, my beginners level research indicated that some knife metal is more flexible or pliable than others.
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The problem is any time you cause the steel to yield (bend) it experiences work-hardening.

I really wouldn't mess with it, but I'm not courageous like others. I would be more apt to file away the parts of the blade making contact and call it a day.
 
It seems to me that if you can bend a blade, and have the bend set, then the blade wasn't properly hardened in the first place.

If the blade bent during use due to a poor heat treat, then you might be able to bend it somewhat straighter, but you still have a knife that isn't properly hardened.

If the bend is actually a warp that occurred during the hardening process, then I don't think you would be able to make it straight.

Either way, I think you would be better served by investing in a new, better knife.
 
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Is this your knife?
If the blade is made of unhardened steel you would stil need some force to bend it like this. Looks like it was used as crowbar.

killgar said:
Either way, I think you would be better served by investing in a new, better knife.
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I agree. You would have a new knife hopefully made of better steel and you could use your bent knife as experiment and try to make it straight.

killgar said:
If the bend is actually a warp that occurred during the hardening process, then I don't think you would be able to make it straight.
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Well, I'm not so sure about that. Check the video.

 
TheOne45 said:
Is this your knife?
If the blade is made of unhardened steel you would stil need some force to bend it like this. Looks like it was used as crowbar.


I agree. You would have a new knife hopefully made of better steel and you could use your bent knife as experiment and try to make it straight.


Well, I'm not so sure about that. Check the video.

Click to expand...

I know that it's possible to straighten hardened blades, but it requires a certain level of skill (or luck), and we're talking about what the OP can do. Like I said to the OP -"I don't think you would be able to make it straight" (referring specifically to a warped, hardened blade).

My guess is that if the OP had skills like the guy in that video, or the ability to modify a hammer in such a way, that he wouldn't have joined Bladeforums to ask if there is a way to straighten his knife. Of course even for a skilled craftsmen it's a tricky procedure, but the OP might be lucky.

Thanks for the video, I found it interesting :).
 
It's an inexpensive Chinese knife, with a missing thumb stud.
I imagine the blade can simply be bent back straight.
 
If the bend is actually a warp that occurred during the hardening process, then I don't think you would be able to make it straight.
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I just found the video interesting and decided to share.

I think it's not OK to make assumptions what someone can do or can not do. If someone is looking for an information we should give him all we know and let him decide what he can or can't do. If nothing else he could find some answers interesting or informative. There are also other members here reading the answers and perhaps someone could use some of the informations we share.

If the knife is hard to use in bent condition I personally would disassemble it, put the blade in the vise and straighten it.
The knife looks like one of those cheap gas station knives and they are usually soft (about 50-52HRc) so they can be bent. But this is just an assumption.
 
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I would try to bend the blade with my hands. I've done it many many times. You may or may not be successful. If you are prepared to make a mistake and not care, this is a great opportunity to learn how to straighten blades. Do a little at a time. Check the bend from above and from the end of the blade, looking down it like. rifle sight. You can almost certainly make it better than it is now. Perfect? Probably not.

There is a small possibility you will break the blade. Wear gloves if you are concerned. I've broken several blades (by hand) doing this. I was not injured. This probably won't happen with such a crazy thick blade like this one. You will probably do just fine.

Best of luck,
Brian.
 
I have a Case XX Sodbuster in chrome-vanadium steel that I was cleaning up when I realized it was bent. I put it into a vise and tried to bend it, but couldn't get it to yield. (Hardened steel has very high yield strength, like a spring.) Then I tried striking it on the concave (shorter) side with a ball-pein hammer. Not sure, but I think that might have straightened it just a bit. Then I abandoned the effort for fear of damaging the knife and learned to live with it.
 
Replace the missing thumb stud and see if it’s easier to open

Honestly try to straighten it. If it breaks throw it away. Its not worth much.
 
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