straightening homogenous steel post quench

H

HSC ///

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I'm starting to forge some homo steel more vs the laminated steel I've been using.
Laminated steel bending and straightening is part of the process as the outer layers are soft.

I've just forged two knives for the kitchen but I know I did them to thin and they won't come out straight out of the quench. In the past I've tried the 3 pins in the vise, the clamping during tempering, and small hammer peening, using a wood bar lever but none have really worked and I snap the blade while trying to straighten,

Can someone guide me as to either how to get the blade straight out of the quench or straighten post quench successfully?

thanks
 
you said the clamping during tempering did not work. did you counter bend twice the thickness (or greater) of the warp ? i lay my blade on the counter top and use coins to see how much warp i have. then i use two of those coins to make the counter bend. i also cool it off while still clamped in the sink filled with with tepid water. usually works on the first try and i rarely have to go thicker than twice the warp thickness. if nothing else works, maybe try it one more time.
 
Here's a method that I was just taught by Dave Lisch. He recently heat treated 5 of my kitchen knives. Take a propane torch to the spine of the blade where the bend needs to happen, heat to some color then use 3 pins in the vice to straighten. This is post quench and post temper. I asked him about ruining the heat treat, and he told me to try not to get any color down to the edge, but if a little color does not to worry about it because heat treating is a combination of temp and time (if I understood him correctly). I have since used this on 5 blades with good results.
~billyO
 
I'm doing it in the temper with a jig like @Matthew Gregory uses. Except with a more reasonable number of screws. There's a learning curve that seems to have more to do with thickness than anything.

Basically a piece of tubing with holes drilled and tapped along the sides and screws opposing each other. It's the same premise as bending over a shim but a little easier to use on a repeated basis rather than finding your shim and your clamp because you used it over there and left it under your pile of old belts and then just said f-it and twisted wire over your straight bar with a penny for a shim and then couldn't find your snips when you pulled it out of the quench so you just chuck the whole works across the shop and make a new knife.

I'll snap a pic of mine when I get home.
 
john april said:
you said the clamping during tempering did not work. did you counter bend twice the thickness (or greater) of the warp ?
Click to expand...
no I didn't counter the bend, just straight plate clamps
ok thanks, I'll remember that
 
weo said:
Here's a method that I was just taught by Dave Lisch. He recently heat treated 5 of my kitchen knives. Take a propane torch to the spine of the blade where the bend needs to happen, heat to some color then use 3 pins in the vice to straighten. This is post quench and post temper. I asked him about ruining the heat treat, and he told me to try not to get any color down to the edge, but if a little color does not to worry about it because heat treating is a combination of temp and time (if I understood him correctly). I have since used this on 5 blades with good results.
~billyO
Click to expand...
thanks, I hadn't considered this method, I know how to do this.
 
I recently did a couple of 10" chef's kinves out of 15N20 that kept warping during heat treat. I tried the same series of clamping, peening, tapping, etc. with no luck. My final effort was to put a shim in the middle and clamp the two blades together opposite the warp and then tempered. Worked perfectly. I also now have two well-tempered 1" C-clamps...
 
weo said:
Here's a method that I was just taught by Dave Lisch. He recently heat treated 5 of my kitchen knives. Take a propane torch to the spine of the blade where the bend needs to happen, heat to some color then use 3 pins in the vice to straighten. This is post quench and post temper. I asked him about ruining the heat treat, and he told me to try not to get any color down to the edge, but if a little color does not to worry about it because heat treating is a combination of temp and time (if I understood him correctly). I have since used this on 5 blades with good results.
~billyO
Click to expand...
I remember this now, I did with James Rodebaugh as I recall, he put the blade edge in wet sand to protect while we drew back the spine/tang
 
HSC /// said:
. . . Can someone guide me as to either how to get the blade straight out of the quench or straighten post quench successfully?
thanks
Click to expand...
Several times I used sand blasting for straightening blade. For kitchen knives it works excellent. Try this as I described here a referred by other member here.
 
On thing to stress out is that straightening should be done in the as tempered state, better if at tempering temperature. With classic methods (counterbending).
On the other side, i have seen people peening blades straight so amazingly i'll have to try it....bead blasting should work the same way.
Here is a youtube link to show how Berardo from ABS does the magic:
 
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One way to deal with warp is to avoid it. I have started taking my long and thin blades directly out of the quench and into the aluminum press plates. Warp is nearly zero when removed a few minutes later. From 900°F to 400°F the steel is still austenite and is very shapeable by the plates.
 
Questions on quench plates.

Standard aluminum like 6061 or are they something special ?
What size plates are common ?
If you were doing a FFG on a kitchen knife would you plate the entire knife or the blade only ?
 
3fifty7 said:
Questions on quench plates.

Standard aluminum like 6061 or are they something special ?
What size plates are common ?
If you were doing a FFG on a kitchen knife would you plate the entire knife or the blade only ?
Click to expand...
Any standard aluminum, ebay is the best place to look, unless you have a good scrap yard near by.
Look for 1" and above on thickness and around 4" by 18" or bigger.
You will plate the whole knife. I do my kitchen knives before beveling.
 
thanks fellas, everything worked out ok,

there is still a slight bend in the longer knife but it's all in the tang and that's easy to fix

S stezann I've tried that peening method but did not have any real success, I even made a special peening hammer. I'll watch the video again and see if I missed anything

Stacy E. Apelt - Bladesmith Stacy E. Apelt - Bladesmith that's what I was looking for, some prevention, I'll try the plates

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thanks
 
stezann said:
Here is a youtube link to show how Berardo from ABS does the magic:
Click to expand...

I tried that once and ended up with a broken blade. Not saying it won't work for you, but Berardo makes it look easy.
 
I didn't try it yet, but when i will i'll make sure to act on a very well tempered blade. If you crack a blade by peening it it might be that something went wrong before peening. Already present cracks, massive cementite in the grain boundaries, large grains and so on.
I don't know if the system would work as well as Berardo makes it look like in case of a really hard (>62 HRC) blade, since i believe it works if you are able to set a plastic deformation by peening...the hammer tip should be harder than the workpiece to begin with.
 
Would it be crazy to clamp some small angle iron or 1/8" mild steel to the sides of these knives spines and quench the whole shabang? Like leave the edge and 1/2 inch or so of the bottom blade exposed? Quench the whole bleeding thing?

Caveat of it might be a stupid idea.
 
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