Fixing bent blade on Shigefusa

Today I received a Shigefusa petty which needs a new handle. I have no idea how original owner managed to bent the blade, but it's bent not in the tip area, but closer to blade!
I've tried to make a few shots to highlight the problem.



The blade is quite flexible towards the tip, but the bent section is pretty stiff. Very stiff I would say. I don't know the story of this knife yet (gonna ask original owner later) but it looks like knife wasn't really used. I examined edge very closely but apart from some minor scuffs I couldn't notice any marks from sharpening. And I have yet to find out how it lost its original handle. The super beefy tang has lots of marks on it from chisel or smth similar… and remains of glue.



While original owner didn't asked me to do anything with the blade, I think if it's possible to fix, it's better be done before I put on new handle.

Can you guys give me any advices here? How to straighten blade here? I'll surely contact original owner before doing anything.

Huh that one is bad ;(

lay it on flat table and push gentle up

Can't tell for sure from pic, but it may be warpage. Is it simply bent up evenly, or does it look like it will take some torgue to bend straight.

Warpage is usually from heat treat, and pretty hard to fix.

I think it's warped, too. I can't imagine too many scenarios in which a user would bend that part of a blade...

Thanks guys. The bent looks a little bit uneven. I imagine that it could be possible to do such thing if someone tried to crack a walnut with it.
Gonna talk to original owner about it. He is a knife enthusiast and might also be KKF member already.
P.S. I actually asked him about any blades that might need new handles, so I could get more practice in handles making. He gave me few and I'm having fun now Damn, even in this condition that Shigefusa cuts better then most of my knives…

The man who owns this blade told me he got it cheap from another KKF member. It was some heavy shelf that fell on this blade and got it bent.
Yet the owner gave me carte blanche on trying to fix blade.
I'm going to try Maxim's offering.

Is that a joke or are you serious?

greasedbullet said:

Is that a joke or are you serious?

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A little of both. If gentle persuasion won't work then maybe a soft faced mallet and a stump might be the answer.

*Note - Please don't use the hammer type above.

Huh. Never would have tried that.

I think sending it to Murray Carter would be a good option. He probably has more experience than anyone else in the US straightening clad blades.

Squilliam said:

I think sending it to Murray Carter would be a good option. He probably has more experience than anyone else in the US straightening clad blades.

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What do you base that statement on? Not trying to be combative, just curious...

All the times i have sold Shig i have never seen single one warped of the heat tread, so i am accusing this one is not, but can be wrong.
If it is not then it is easy fix

Definitely doesn't sound like typical Shigefusa, either.

I've seen knives where people had a handle that was installed improperly and twisted and torqued the blade to try and align it back with the handle....not that this is what happened here, just another example of how a knife can end up warped.

The rubber mallet actually seems pretty legit to me.

The isn't Shigefusa fault, that knife was accidentally bent by a fallen shelf. Pretty heavy shelf I guess. At least that the story I've been told.
Since I do own rubber mullet I tried it this morning. I was very afraid of just braking blade so didn't apply much force… that might be the case.

I tried clamping blade similar to this video http://www.youtube.com/watch?v=CL2XxWyVfGM but without any heating. Gonna leave it clamped till tomorrow and see if it makes any differences.

There is also the wooden block with a slot technique which, in my limited experience, is a gentle and forgiving way to fix a bent blade. Here is a video link that illustrates the process, more or less. I use a pine 2x4 (scrap wood from making a sink bridge).
Here is the video:http://www.youtube.com/watch?v=gzM5R5fHzkQ
I promise that I do not work for the company that produced it.

I have seen that method with a slotted board before too.

Dave Martell said:

A little of both. If gentle persuasion won't work then maybe a soft faced mallet and a stump might be the answer.

*Note - Please don't use the hammer type above.

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+1

bending the blade or clamping it does not normally fix this issues, it will go back to "true" in this case bent!

Not sure how mutch force the shig can take but there are some levels on how to fix it

1 wodden stump and a wodden hammer and try hitting the bump
2 wodden stump and a brass hammer
3 iron stump and brass hammer
4 iron stump and a slightly round faced hard hammer

I've straightened hardened bars in the past using a vise and 3 pieces of hardwood dowel to apply point pressure to the bend. Can usually reverse the bend enough to remove it without snapping the bar. Not sure how ideal it'd be for a knife, but the concept provides some control without as much psychological stress as smacking the knife with a hammer.

The slotted board technique looks pretty good, IMO.

Thanks Sabaki.

You were right about clamps — after 24 hours they didn't help (if only a tiny bit). Gonna try again hammer again.
Do you think I need a wooden hammer? I already have soft faced mallet and would only buy wooden hammer if it works really different compared to soft mallet.

You need a hammer and an anvil. The rule is that it needs to be straightened in the same manner that it was bent. In this case, a hard metal object. The cladding is soft so it will straighten easily but will require some refinishing afterward.

Hoss

The vise and dowel trick mentioned by XoomG has worked for me many many times on Case pocket knives and vintage Sabs. I guess they must be fundamentally different from a Shigefusa---they're not clad, anyway.

OK I tried to be gentle. Few days in a row I hugged Shig in vise trying to bend it back. No luck. So I took a hammer and give Shig a few hits. Worked like a charm. Soft mullet wasn't doing anything, but plain old hammer with just a few (not really hard) hits allowed to fix blade.

Thanks Devin! I wouldn't probably dare to hit someone's Shigefusa with hammer if it wasn't your advise

icanhaschzbrgr said:

OK I tried to be gentle. Few days in a row I hugged Shig in vise trying to bend it back. No luck. So I took a hammer and give Shig a few hits. Worked like a charm. Soft mullet wasn't doing anything, but plain old hammer with just a few (not really hard) hits allowed to fix blade.

Thanks Devin! I wouldn't probably dare to hit someone's Shigefusa with hammer if it wasn't your advise

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What do you mean "hugged" it in a vise? Just clamp the whole thing? I don't know why anyone would think that's a good idea. Get some dowels or something else in there and reverse the bend.

XooMG said:

What do you mean "hugged" it in a vise? Just clamp the whole thing? I don't know why anyone would think that's a good idea. Get some dowels or something else in there and reverse the bend.

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I wasn't clear, sorry. I actually did exactly what you've written: used 3 dowel, one from one side and two from another. Similar to what described in this video http://www.youtube.com/watch?v=CL2XxWyVfGM

Anyway, hammer helped. Now I do need to polish blade but I would do it anyway.

Pics? Curious to see before and after, especially hammer marks (if any). Too risky for me.

Gonna take some pictures tomorrow… it's already late evening here and I have no power to do anything knife related (other then reading KKF)

Here's a crappy picture of spine. It looks straight. Not perfectly straight, but much better then it was before.



And here you can see scars from hammer. Also I tried magic marker trick to make sure the entire length of the blade touches the stone. You can also note a little chip on the heel.



After few minutes of sharpening and examining blade I can't say it's perfectly straight. Yet now it's possible to sharpen on stones. Had I had more time with hammer I would have have achieved a little bit better results, but hitting someone's Shigefusa cost me too much nerves, so I guess I'm gonna stop at this point.

Time to polish, sharpen blade and make a new handle. Thanks to everyone for advices!

i have been following this one since its beginning. respect for hitting someone else's shig with a hammer! :eek2:

Looks good, please post pictures of the finished product.