Warped tang! No problem.

John Barker

John Barker

SUPERModerator & KNIFE MAKER
Well, I haven't had any warped tangs in a while. I taper all my tangs before heat treat and up to now, I haven't had any real warpage issues. Saturday, when I heat treated 4 CPM 154 blades, I noticed the foil shrink very fast when I pulled them out of the kiln and I thought I was in trouble. I put them in the quench plates right away. I usually do this one blade at a time. After the quench, the first blade's tang was pulled in line with the flat side of the blade. I put it in my vise and tried to straighten it out. No good. All four of them did the same thing. So, I thought about heat treating them again. Guess what? I didn't have enough foil. So I remember some of the pro heat treating guys talking about clamping something during the temper. So that's what I did. I had a piece of 1/4" thick D2 about 11" long. I clamped the blade with 2 clamps with the warped tang sticking out away from the D2. Then I clamped the tang with 2 clamps so the tang was flat against the D2. Then I temeperd it twice. When I unclamped everything it was right on the money. I did this with 2 of four blades. I have 2 more to do. So far so good. Just wanted to pass this along.
-John
 
Here's some pics.
First you can see the tang in ling with the side of the blade on the bottom.
e-nep001.jpg

Then the tang pulled away on the other side.
e-nep007.jpg

Clamping it down
e-nep008.jpg
 
I clamped it so it pulls the tang against the steel as was shown in the second pic.

Then after one temper. Much more symmetric.
e-nep010.jpg

e-nep011.jpg


-John
 
Excellent work, JOhn. Thats why your one of the best in the bizz brother. Do what it takes to get the job done right with great results.

Right on, happy it worked for you!!!!

Chris
 
Thanks Chris, but I'm still really a noob. One more temper and it will be finished. I'm not going to clamp it on the second temper.
-John
 
John,

I had the pleasure to buy one of your Houdstooths a couple years ago. I wouldnt consider you a noob man......lol Your grinds and edges are Crisp as they come2thumbs I am what they call a Noob....lol

Cant wait to see these babies finished up, John!!!

Chris

John Barker said:
Thanks Chris, but I'm still really a noob. One more temper and it will be finished. I'm not going to clamp it on the second temper.
-John
Click to expand...
 
Hey Doc, just send me those warped ones. Line up perfect on my warped body.
You just lucked up...Now you getting alot of skills. Gee did I hear that mill fire up???
 
John,

I do the same with 1095. For some reason I always get warps with 1095.
1080 is never a problem. Never a prob. with CPM154. Don't know why.

Greg
 
Great idea!

At what temperature do you temper at, high or low temper?

Will this work for carbon steel blades aswell?


Regards Jakob
 
Hey John, another good idea is to rough out the hollows in the tang pre heat treat but leave most of it flat and grind the taper after ht. Once I started dong this I had way less warpage.

Todd Begg
 
Todd,
Thanks for the post. I've done that a few times too. This was really the first time I had issues. But, I'll keep that in mind. Thanks again.
-John
 
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