Straightening warped blades after heat treat

Belstain

Belstain

Joined
Sep 17, 1999
Messages
320
Most of my blades are warped after heat treat. How should I staighten them without breaking them.

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I'm a Schizophrenic and so am I
 
Belstain,
First you must be a little more specific about what kind of steel you are using and the method of heat treating.A number of things may be causing this problem.If you are treating with a torch you may be applying to much heat to one side.If you are using standard carbon steel just anneal it,straighten it and re-heat treat.Dave
 
My rescue knife I made had a 3" blade and it was the first one that ever warped on me. It was 1/8" thick and since it was so short and stout I had enough there to flat plane the whole thing to get rid of the curve. I ended up with a plenty stout blade in the end. Now if it had been a longer blade with 1/8" I could have had to do what Dave said. Cory

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" I am a shootist."
Clay Allison
" Does this mean we are bladists?"
Vaquero57
McAlpin Bladesmithing
 
Normally after you pull the blade out of the quenching oil it should still be soft enough to straighten. I put the blade end in a slightly open vise and gently straighten the blade. This has to be done fairly quickly, as the steel gets cooler it becomes more brittle and you risk breaking it. If it wont straighten then you have the two options already mentioned above.

Arthur D. Washburn
ADW Custom Knives
www.adwcustomknives.com
 
I have been using 1/8" 1095. I do it in my forge. I think I will try beowulf's way. How long should I leave it in the quench?

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I'm a Schizophrenic and so am I
 
You could also try normalizing your blades after grinding and before heat treat...

Bring them to non-magnetic and then let them cool down...This can be done as a seperate step or while you heat treat...This will help to remove the stress from grinding...

Many people who forge will do this two or three times before the final heating and quenching...We've had really good luck with this, although some blades just don't want to play...

Bending blades before tempering can be tricky and you might break a blade...Easier to bend and less likely to break after tempering...

Running Dog

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Running Dog Knife Company
http://www.runningdogknife.bigstep.com
runningdog@dog.com
mmurphy@premier1.net
 
I straighten blades after hardening and tempering in a three-point fixture in my bench vise, (thanks TOMO!) heat the blade up gently in the area that has to bend with a small propane torch, as if you were tempering it. and squeeze away. As long as you do it very warm but don't get too hot you wont hurt a thing(usually)Watch out for a very hard blade,or one that is too warped. Sometimes you have to go back to anneal stage as has been suggested. Heck, Ive been known to straighten tangs cold, but they weren't hard.
 
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