How do you fix a bent blade?

This forum is for those who like to repair and restore knives, and for those who would like to learn.
Post Reply
User avatar
MikeEngland
Posts: 394
Joined: Tue Oct 04, 2011 9:31 pm
Location: Wauseon, Ohio

How do you fix a bent blade?

Post by MikeEngland »

Is there any safe/smart way to straighten a bent or warped blade?
gotyerknifeonya?
User avatar
Iron Hoarder
Posts: 1808
Joined: Sat Jan 16, 2010 3:03 pm
Location: Chertsey, Surrey, UK
Contact:

Re: How do you fix a bent blade?

Post by Iron Hoarder »

Very gently in a vise with three pieces of brass rod. Two on one side and one on the other.
I measure my collection by the ton.
Whoever dies with the most tools wins......Now accepting donations.
User avatar
FRJ
Posts: 16242
Joined: Fri May 14, 2010 1:43 pm
Location: Ct.

Re: How do you fix a bent blade?

Post by FRJ »

That does seem like a very smart method.
Joe
User avatar
OLD GAR
Posts: 248
Joined: Wed Sep 02, 2009 11:10 pm

Re: How do you fix a bent blade?

Post by OLD GAR »

Just be ever so careful though. Many of the high quality knife blades are near 50+ Rockwell "C" scale hardness. That is why you see broken blades on really good knives - - enough to make you want to cry. On the other hand if it bent, ::tear:: you might be straighten it out ::woot:: .
Suburbia: where they tear out the trees & then name streets after them.
User avatar
whitebuffalo58
Posts: 2743
Joined: Tue Aug 17, 2010 2:35 am
Location: SW MO Heart of the Ozarks

Re: How do you fix a bent blade?

Post by whitebuffalo58 »

Just an observation. Did ya ever notice that it's not that hard to bend a knife blade, but it's nearly impossible to bend it back? Why is that? ::hmm::
A couple of times, i've gotten away with cold forging a bend out on a flat anvil. I used an 8 oz. detailing hammer and just let the weight of the hammer do the work. Took my time and little by little it eventually worked the blades to very near straight. I stopped as soon as the blades were able to function properly. (I didn't see any need for pushing my luck)
It left a few light hammer marks, but the times I did it were on EDC knives, so I wasn't real concerned with clean up on the blades. Probably wouldn't have taken much more then some light sanding though.
My brother once pointed out that a blade can be lightly "warmed" as long as you don't warm it to the point of getting color. Haven't had the opportunity to try it, but thought maybe warming in a toaster oven to say 250-300 degrees might help reduce the chances of breaking while forging. ::shrug::
Bottom line is, every method is risky, short of removing, heating, straightening and reheat treating. Well, I guess that's even risky...just a different kind of risky. :D
knifemaker3
Posts: 582
Joined: Tue Nov 25, 2008 10:56 pm
Location: Southern Missouri
Contact:

Re: How do you fix a bent blade?

Post by knifemaker3 »

OLD GAR wrote:Just be ever so careful though. Many of the high quality knife blades are near 50+ Rockwell "C" scale hardness. That is why you see broken blades on really good knives - - enough to make you want to cry. On the other hand if it bent, ::tear:: you might be straighten it out ::woot:: .
I think you meant 60+ Rockwell "C" scale....or at least I hope so :lol:
God Bless!

Craig Blankenship
Booger County Outfitters LLC.

Maker of Custom Knives and Custom Screenprinted Garments
User avatar
Diligence
Posts: 446
Joined: Thu Jan 04, 2007 5:43 pm
Location: Alberta

Re: How do you fix a bent blade?

Post by Diligence »

The most surefire way I've ever used to fix bent blades, was to very carefully tap it on the side of my stiddy to straighten it out....then just give it one more firm tap to be sure it was straight, have it break, and make a new one.

lol...seriously though, I've only had marginal luck straightening bent blades. Sometimes it works and sometime it doesn't as far as I have experienced, and it depends on the type of steel, hardness and tempering that was used.

J
gringo
Posts: 2033
Joined: Sun Mar 02, 2008 7:17 pm

Re: How do you fix a bent blade?

Post by gringo »

how bent???
photos please.

dudley should chime in here...since swords have issues with being bent more often than knives.

in fencing class...
if you bent your foil, the correct method of straightening the blade was to place the sword tip down, at an angle, and step gently on the blade at the point of the bend.

might be difficult to step on a pocket knife and come away happy.
User avatar
orvet
Gold Tier
Gold Tier
Posts: 19543
Joined: Tue May 16, 2006 6:23 am
Location: Willamette Valley, Oregon

Re: How do you fix a bent blade?

Post by orvet »

gringo wrote: might be difficult to step on a pocket knife and come away happy.
:shock:



::rotflol:: ::rotflol:: ::rotflol::
Thanks Donald, I needed that!
The visual in my head was too funny! :mrgreen:
Dale
AAPK Administrator

Please visit my AAPK store: www.allaboutpocketknives.com/orvet

Job 13:15

"Buy more ammo!" - Johnnie Fain
“Evil is Powerless If The Good are Unafraid.” – Ronald Reagan
User avatar
glennbad
Gold Tier
Gold Tier
Posts: 7807
Joined: Mon May 15, 2006 11:13 am
Location: NH

Re: How do you fix a bent blade?

Post by glennbad »

I've had very little luck straightening a bent blade. The only time it works for me is during crinking, where I find the tangs can be a little softer and can be tapped some with a hammer. Near the tip, not so much... ::dang::

I have a swiss army knife where the main blade is slightly bent, and doesn't sit right on the close. Every few months, I discover it again and try to bend it back. Haven't succeeded yet...

Glenn
Post Reply

Return to “Knife Repair and Restoration”