Warping during heat treat...

[viral]

So I am using 1084 and heat treating in a forge. I'm quenching in canola. I forge my blades. Do 2-3 normalizing cycles then go for heat treat. Nearly every full tang knife I do kinks either way on the handle. I am assuming it's because the tang is a different temp. Even when i submerge the entire blank in the pre heated canola I get a tweak in the handle. Is there any way to avoid this? I get aggravated always trying to correct that issue later on. I do not have a surface grinder and am running a grizzly 2x72 so just cleaning up my tang to flat isn't really optimal.
Any advice? Tips? Maybe even some tricks?
Thank you in advance.

 

[Ninja Blacksmith]

I have experienced this on a few full tang O1 blades I've done. Now, when you say "tweak", do you mean the warp has a vertex shaped like a V? Or is the entire tang warped into a shallow U shape instead? If most of the tang is still straight and if there's no corkscrew twist, you could clamp the blade to a metal plate that is not warped with coins or something else at each end to prop the blade off of the plate surface a few mils, with the clamp directly over the vertex of the warp, and re-temper at a slightly higher temperature for an hour or so, letting it cool by air. It's not a 100% warp-free guarantee method, but I've had a fair success rate using it.

 

[viral]

I have experienced this on a few full tang O1 blades I've done. Now, when you say "tweak", do you mean the warp has a vertex shaped like a V? Or is the entire tang warped into a shallow U shape instead? If most of the tang is still straight and if there's no corkscrew twist, you could clamp the blade to a metal plate that is not warped with coins or something else at each end to prop the blade off of the plate surface a few mils, with the clamp directly over the vertex of the warp, and re-temper at a slightly higher temperature for an hour or so, letting it cool by air. It's not a 100% warp-free guarantee method, but I've had a fair success rate using it.

Currently I'm just trying to clamp and temper straight but in a perfect world I don't want to do that to every full tang knife I do. It usually tweaks and does the nice U bend. It doesn't usually twist. And it almost always does it where my pin holes are. I don't know if that had something to do with it or not. But I have great results with stick tangs. So I don't really know...

 

[Ninja Blacksmith]

It could be due to different temperatures. When you heat treat, do you use a forge or an electric kiln? If the problem is due to temperature, it could be that one side of the tang area is getting hotter than the other. I don't have a kiln, but when using my forge to heat treat, I try to rotate the knife (much like rotisserie chicken) once it reaches the target temperature for soaking, which has reduced my own warp problems down to maybe 1 out of every 8 or so knives - and barely perceptible, easy-fix warp at that, too. Each maker's shop setup is like a fingerprint, no two are the same, so what worked for me may not for you, but you can always make a mild steel blank to do a test run to see if maybe one side is getting hotter.