I'm making a gyuto out of A2, but got a little warp at the tip after heat treat and temper. There isn't enough material to grind it out I Heat treated to 1750 and clamped to cool down. Then I tempered at 400 for 2 hours without clamps (couldn't fit them in the heat treat oven). Could tempering a second time at 400 for 2 hours clamped remove the warp? I'd need to put it in my conventional oven at home to fit the clamps. And is there any danger in putting aluminum or painted clamps in an oven for 2 hours?
Removing warp from A2
- Thread starter West164
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Welcome to the party 
This is something you'll need to master dealing with, especially if you get into forged blades. Figure out how to make it as painless as you can for yourself now....there will likely be many, many, many more.
Don't use aluminium clamps, they'll probably fail if you heat them under load. The paint will probably be ok, but I'd invest in steel clamps. Doing a shimmed temper should correct the warping, but keep in mind a household oven is not calibrated like a HT oven and may considerably overshoot your target temp. Test it out with a separate BBQ type thermometer to see where your target temp actually is on the dial. I had a toaster oven that overshot its dialed temp by 90 degrees F.
If it doesn't work, try drawing back the spine with a torch and try it again. If that fails, try peen straightening.
I don't know if you pre-ground it, but I quit pre-grinding air hardening steels and deep hardening low alloy steels early on because I was wasting sooo much time straightening blades. It's much more economical to just use the extra belt or 2 and grind from full thickness bar stock after profiling.
Good luck
This is something you'll need to master dealing with, especially if you get into forged blades. Figure out how to make it as painless as you can for yourself now....there will likely be many, many, many more.
Don't use aluminium clamps, they'll probably fail if you heat them under load. The paint will probably be ok, but I'd invest in steel clamps. Doing a shimmed temper should correct the warping, but keep in mind a household oven is not calibrated like a HT oven and may considerably overshoot your target temp. Test it out with a separate BBQ type thermometer to see where your target temp actually is on the dial. I had a toaster oven that overshot its dialed temp by 90 degrees F.
If it doesn't work, try drawing back the spine with a torch and try it again. If that fails, try peen straightening.
I don't know if you pre-ground it, but I quit pre-grinding air hardening steels and deep hardening low alloy steels early on because I was wasting sooo much time straightening blades. It's much more economical to just use the extra belt or 2 and grind from full thickness bar stock after profiling.
Good luck
Thank you! The clamps are steel, but I have aluminum shims. I got it to 62 Rockwell the first time around, so I'm nervous about using my home oven. I thought about tempering for 2 hours, remove them shim and clamp. Would that work the same as clamping during temper?Welcome to the party
This is something you'll need to master dealing with, especially if you get into forged blades. Figure out how to make it as painless as you can for yourself now....there will likely be many, many, many more.
Don't use aluminium clamps, they'll probably fail if you heat them under load. The paint will probably be ok, but I'd invest in steel clamps. Doing a shimmed temper should correct the warping, but keep in mind a household oven is not calibrated like a HT oven and may considerably overshoot your target temp. Test it out with a separate BBQ type thermometer to see where your target temp actually is on the dial. I had a toaster oven that overshot its dialed temp by 90 degrees F.
If it doesn't work, try drawing back the spine with a torch and try it again. If that fails, try peen straightening.
I don't know if you pre-ground it, but I quit pre-grinding air hardening steels and deep hardening low alloy steels early on because I was wasting sooo much time straightening blades. It's much more economical to just use the extra belt or 2 and grind from full thickness bar stock after profiling.
Good luck
Possibly, but probably not. Pressure and time at temp will fix the warp. Just clamping may not give the steel enough time to move since it will cool very quickly. I'd have probably cold straightened it with a hammer if I were in your position. It's not as crazy as it sounds.
You won't hurt your oven by using it to temper, just be sure you know what the actual temperature is.
I don't have a carbide hammer, do you know of any tricks to get around that? Maybe hitting a ground down drill bit?
How thick is the blade stock? Has it been pre-ground? Was it foil wrapped during austenitizing?
Blade stock is about .100" and it was wrapped. It was pre-ground and I think I got it a bit too thin before heat treat.
Yeah this will be tricky, If shimmed tempering doesn't fix it, the default is basically peen straightening. A punch and hammer will do it too, no need for a carbide hammer necessarily.
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I really find just profiling, and leaving the blade flat then plate quenching is much more worth it as far as time saving for air hardening steels.
Its easier for me to grind hardened steel. Than to quickly fix a wobbly blade. Even the really wear resistant stuff. Grinding isnt that bad. Its just the finishing part that gets hard.
Its easier for me to grind hardened steel. Than to quickly fix a wobbly blade. Even the really wear resistant stuff. Grinding isnt that bad. Its just the finishing part that gets hard.
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