Warp help.

[MBurks]

I'm working on my first bowie, Aldos 1075, blade about 7 inches, big knife for me.

I did some mild forging to get the shape and bevel started, then profiled and ground in the bevel.

I thermal cycled here, in a forge.

Steps were well above critical, cool to black, non magnetic, cool to black, full red and still magnetic cool to black.

I soaked in vinegar to remove scale then Claude and heat treated, brine into oil.

I picked up a little bit of a warp about a third of th way from the tip.

I've tempered twice already, the first at 380 the second with the blade clamped to straighten the warp at 425.

I still have a bit of warp and I don't know whether to try tempering again, (not sure of the hardness) or just re heat treat.

Could anyone make a guess on what temp and time I could temper at that will be enough to get the warp out but not drop the rc too much more, or should I redo the heat treat?

Thanks and merry Christmas everyone!

 

[kuraki]

In the first temper you can get away with clamping straight but in the second you need to clamp with a counter bend. You can temper at 420 again with a counter bend without affecting your hardness. I would try an hour with a slight counter bend.

 

[MBurks]

In the first temper you can get away with clamping straight but in the second you need to clamp with a counter bend. You can temper at 420 again with a counter bend without affecting your hardness. I would try an hour with a slight counter bend.

Ok thanks, I did clamp it with a couple pennies to over bend, and got some of the warp out but not quite all of it.

I was worrying about effecting the final hardness with too many tempering cycles so that makes me feel better.

Thanks so much I will try it again.

 

[Don Hanson III]

Too late, but they are easy to straighten right out of the quench, you have about one minute to do this.

What Kuraki said will get you straightened out. You also don't need to go has hot. 400 or a bit less will work. No hardness loss with multiple tempers either

 

[kuraki]

Ok thanks, I did clamp it with a couple pennies to over bend, and got some of the warp out but not quite all of it.

I was worrying about effecting the final hardness with too many tempering cycles so that makes me feel better.

Thanks so much I will try it again.

So I'm clear and you're specific, you had two pennies under your blade at the apex of the warp and it was clamped over them so each end of the blade were on your clamp surface/bar/whatever? That seems like quite a bit for a little warp. Are you sure you're actually at 400F? Is this your kitchen oven? Can you verify with another thermometer? I'm surprised you're not warped the other way.

 

[MBurks]

Thanks losing hardness was what I was concerned with.

I've been pretty lucky with warp so far, the few I've had straightened right up on the second temper if I didn't fix it after the quench.

I'm not completely sure this one didn't happen during the first temper cycle because I sure didn't see it before.

 

[MBurks]

So I'm clear and you're specific, you had two pennies under your blade at the apex of the warp and it was clamped over them so each end of the blade were on your clamp surface/bar/whatever? That seems like quite a bit for a little warp. Are you sure you're actually at 400F? Is this your kitchen oven? Can you verify with another thermometer? I'm surprised you're not warped the other way.

No. The warp begin maybe 2 inches from the tip, I put 2 pennies at the tip,just far enough back for the blade to cover the pennies, than put one c clamp right where the warp began, then tightened the clamp until I thought I had compensated enough for the warp.

I think I just didn't tighten the clamp enough the first time, I did the same thing again with a little more pressure and got it straightened.

The first time got rid of some of the warp I was just concerned about the effect of multiple tempers.

I appreciate all the help it's straight now and I didn't have to heat treat again.

 

[kuraki]

Ah I see. Glad you got it worked out.