Bent my BK9, how do I fix?

M

mac_heath

Joined
Aug 27, 2002
Messages
178
I got a new BK9 from Tomar's for Christmas. Excellent service from them, and a fine knife overall.

I've been using it for splitting wood. I pound it through the end of a small log (already pre-split into halves or thirds) to get smaller stock for my chiminea. The wood is alligator juniper, which usually splits easily. Today, I pounded it through a piece I knew had a knot, though I started off to the side of the knot. Turns out it had several smaller knots inside. The log was stubborn and I almost pulled the blade out when it began to crack. It split messily, two cracks instead of one. When I removed the blade, I could see that it was bent.

My triangle square shows about a 1/16" curve in the blade. I've tried placing the blade between books and stepping on the bend to straighten. Apparently, 190lbs isn't enough to straighten it out. Ideas?
 
well, any woodworker knows that knots are practically stones (silicated even on many trees)... so "no wonder". i've bent an AXE on some hidden knots on one occasion.

with the axe at least, i got it 95% back with some peening, the old fasioned way (hammer and sickle ring a bell?)

first, put on some safety goggles ;)

with you knife? well... try clamping it between two boards in a vice. leave it for a while.

no? then you'll need to make a little jig, pardon the text:

Code: 
[FONT="Fixedsys"]
==================================
                                   []
    -----------------------xx-------------------------
    []                                                              []
==================================
[/FONT]

where === are the boards in the vice, --- is your blade, and the [] represent blocks, on the blade, surround the bend xx... apply pressure gradually, stop often and check... and don't overdo it... this may turn the trick. the boards and blocks should be at least as wide as your blade.

or you could jam it into a log and use body weight... but the vice method will be more accurate i'd expect. regardless, you get get a slight wave/bend you can never quite remove.

enjoy!


Bladite
 
Last edited:
That sucks!
I freaking hate knots. It binds the blade and there's ALWAYS a chance you'll damage the knife. However, I do not think it should impair performance.
 
The knife should not have bent, regardless of a knot or not. I would contact Tomars and see about a replacement. It sounds like the heat treat was a touch off. With a RC of 58-59, it should flex about 20 degrees without deformation. The blade should break before taking a bend. I have battoned my BK9 through several oak knots and have had zero issue. I could see the blade flex, but it popped back to true when it came out the bottom. :D
 
mac_heath said:
I got a new BK9 from Tomar's for Christmas. Excellent service from them, and a fine knife overall.

I've been using it for splitting wood. I pound it through the end of a small log (already pre-split into halves or thirds) to get smaller stock for my chiminea. The wood is alligator juniper, which usually splits easily. Today, I pounded it through a piece I knew had a knot, though I started off to the side of the knot. Turns out it had several smaller knots inside. The log was stubborn and I almost pulled the blade out when it began to crack. It split messily, two cracks instead of one. When I removed the blade, I could see that it was bent.

My triangle square shows about a 1/16" curve in the blade. I've tried placing the blade between books and stepping on the bend to straighten. Apparently, 190lbs isn't enough to straighten it out. Ideas?
Click to expand...
Wow:eek: My new one was more bent than your used one. Getting mine replaced.
 
I tried to take pics, but the camera cannot focus on the narrow gap. If I place the straightedge across the blade, I can fit a standard business card plus a little through the gap in the center. So maybe we're talking 1/32 instead.

Still, it's noticeable and feels odd in my hand.

Bladite, thanks for the description and picture. Now all I need is a vice large enough. Sounds like a good reason to go shopping for tools.

I have to say that overall, the steel has been exemplary for holding an edge. I touched it up a bit out of the box, re-profiling the edge a little. It was shaving sharp when I finished. After pounding the blade through several logs, cutting kindling, shaving fuzz sticks, and even chopping a log, it remained shaving sharp.
 
I'm surprised it would take a set also. Contact Kabar and see what they say.
 
mac_heath said:
Bladite, thanks for the description and picture. Now all I need is a vice large enough. Sounds like a good reason to go shopping for tools.
Click to expand...

or you could make a jig, on a 2x4, and build up wedges... more primitive, but straight forward. sounds completely fixable.


Bladite
 
The best thing you can do is contact KA BAR

Phone number: 1-800-282-0130

They will help you.
 
Thanks for all the comments. I've contacted Ka-Bar, we'll see what they say. If it's a no, then I'll go about trying to re-straighten it.
 
CRKS said:
The best thing you can do is contact KA BAR

Phone number: 1-800-282-0130

They will help you.
Click to expand...

Tom, You the man who sent me my BK9. Been having all kinds of fun with her. Love the blade. I need a BK7, light and fast, to complete the set. :D
 
CRKS said:
The best thing you can do is contact KA BAR

Phone number: 1-800-282-0130

They will help you.
Click to expand...

Tom, You the man who sent me my BK9. Been having all kinds of fun with her. Love the blade. I need a BK7, light and fast, to complete the set. :D
 
Wow. That is pretty unusual. I have seen BK9s come through much worse than some flexing with no damage. I wonder if there is a chance that this particular BK9 was already slightly warped from the beginning (during the heat treat maybe) and it just went unnoticed until now.
 
matthewdanger said:
Wow. That is pretty unusual. I have seen BK9s come through much worse than some flexing with no damage. I wonder if there is a chance that this particular BK9 was already slightly warped from the beginning (during the heat treat maybe) and it just went unnoticed until now.
Click to expand...

I wondered that also?
 
cody1 said:
I wondered that also?
Click to expand...

It usually takes a pretty substantial bend to make a knife bend permanently, especially one that is tough as Ka-bar's 1095 typically is. It just seems more likely that the BK-9 was already bent and the heat treat is the most likely place for that to happen.

I will be interested to see how the good folks at Ka-bar respond. They are good folks so don't hesitate to contact them.
 
matthewdanger said:
It usually takes a pretty substantial bend to make a knife bend permanently, especially one that is tough as Ka-bar's 1095 typically is. It just seems more likely that the BK-9 was already bent and the heat treat is the most likely place for that to happen.

I will be interested to see how the good folks at Ka-bar respond. They are good folks so don't hesitate to contact them.
Click to expand...

well, if i was batoning a knife through a log, and encountered a too hard knot, that the knife was deflected to go around... and i kept batoning through it anyway when it was binding, and kept at it... well, it's going to get work hardened i'd think. just a guess.

i'd bent an axe head by chopping a surprise knot. threw sparks too. mostly fixed that axe with a hammer and a anvil (without heating), and could always do more; the edge never chipped, and it takes quite an enduring edge, so, i'd guess the heat treat is just fine.

if you goto Blade Show, on the FAR right tables, with the ABS guys, there's a lot of bent blades :> course, those were torture tested ;)


Bladite
 
You must log in or register to reply here.
Back
Top