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Heat treat issue

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SpikeC

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When I heat treated the blade that I just made I heated to 1500º F. and soaked it for about 5 minutes after the oven returned to heat, and quenched in a slow quench oil from McMaster-Carr. The blade is single bevel, flat on one side. After quenching the blade took on a gentle curve over the whole length away from the side with the bevel. The thickest point on the spine is 3/32" thick.
My next blade is going to be ground on both sides, so am I likely to see a repeat of this warp in some way? Was the warp a result of insufficient soak time in the oven? And is there any way to correct this.
As it is, I don't see this as a problem for the things that I want this knife to do, I think that the curve might help when sliding down the side of a chicken carcass, for instance, butt I will know better when I get around to boning the body of the chicken that I roasted last night.
Any insight or help would be very much appreciated!
 

Larrin

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Welcome to heat treating! Warping is common, I don't know of any good ways of preventing it, mostly you have to learn how to fix it. There are several methods for doing so. You might pick up tips on a site like bladeforums.com.
 

DevinT

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What steel is it?

It's best to grind after heat treat to avoid warping.

Hoss
 

SpikeC

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The steel is O1. I can't imagine shaping the blade before heat treating.
 

l r harner

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single bevels will aways trun on you in quench its a stress thing
and since you are using thin stock and its O1 it will harden all the way through. jsut shape the blade and HT it then grind the bevels. on a side note if you HT then grind a single bevel the stressed build form the other side and can make the blade take a bend also (no ffree lunch with single bevels )
 

SpikeC

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Thanks, that is what I was afraid of! I may have been able to straighten it out during the quench as I have seen done, but I didn't have the chops to do that!
Next knife is double bevel, can I grind the bevels on that before HT?
 

DevinT

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Buy good belts and grind after heat treatment.

Hoss
 

SpikeC

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Thanks, Devin. I have a ShopSmith 6X48 belt sander and belts ranging from 36 to 320 and pretty much everything in between. The machine has variable speeds. I did the grind on this first knife at the slowest speed, but I can speed it up as long as I don't over heat the edge, which is what I was afraid of doing.
 

SpikeC

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single bevels will aways trun on you in quench its a stress thing
and since you are using thin stock and its O1 it will harden all the way through. jsut shape the blade and HT it then grind the bevels. on a side note if you HT then grind a single bevel the stressed build form the other side and can make the blade take a bend also (no ffree lunch with single bevels )
So what might happen if I grind a hollow into the flat side of the knife now? Is it likely to make the situation worse or better?
I stripped a chicken carcass with it last night and it worked a charm, so now it is just experimenting to see what happens!
 

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