HT on an Aga top plate...

[PaulSanderson]

Sorry if this is in the wrong place mods, please feel free to move it.

Just wondering if anyone has HT'd on an Aga?? I have tempered in mine a number of times, but yesterday I noticed the Aga top plate had been left on with the lid down...and when i lifted the lid, it was cherry red hot. Could this be used to HT 01 steel?? Before I go out and buy thermocouple leads for my multimeter I just wondered what other people thought...and if anyone had tried it. I have a lovely un-HT'd blade just waiting for treatment but i dont want to ruin it if this is a bad idea.

...many thanks...

 

[robin wood]

Are you talking hardening or tempering? I would be surprised if it got to hardening temp even if the plate itself was showing a little colour. It would be good for tempering a previously hardened blade particularly differential tempering if you want to draw the temper by putting the back of the knife on or very close to the plate and let the colour run toward the edge. The only danger is that the tip could get the heat earlier being closer to heat, you could play with having the tip hanging over the edge not in direct contact. Perfect temper like this would giove you a blue (springy) back and straw or bronze edge. Alternatively you could temper first in the oven to giove you your straw all over then use the plate to soften & toughen the back a little if that was what you wanted.

 

[PaulSanderson]

cheers robin...never thought of the selective tempering side of things. I was referring to hardening which i realise for 01 is around 820-840-ish. I was surprised the plate was a bright cherry red (i wondered if it was safe) i thought if ceramic coated enamel (i think) could get cherry red, then maybe 01 could to. will definitely try the selective tempering on it though...cheers.

 

[Shinken]

I think you will have a job selective hardening 01 on the plate, i dont think it will get hot enough quick enough. i use a jig that is like a slot in a solid piece of metal and when that is glowing orange it just about works. You might find it different but i have doubts. Prove me wrong and have a go. As long as you dont go more blue than brown you will be okay. But be quick with some water to hand it will catch you off guard

 

[Shinken]

Also if all you want to do is harden then thermolight bricks with a 30-50mm blowtoch head works a treat, just lay the bricks with a cavity in middle and direct the torch onto it. actually gives you nice control as you can take torch away for few sec's to check colour when about right check with magnet. hey presto

 

[tobes01]

If that Aga's running on anything other than solid fuel then you need to get your thermostat repaired...

 

[robin wood]

I think you will have a job selective hardening 01 on the plate, i dont think it will get hot enough quick enough. i use a jig that is like a slot in a solid piece of metal and when that is glowing orange it just about works. You might find it different but i have doubts. Prove me wrong and have a go. As long as you dont go more blue than brown you will be okay. But be quick with some water to hand it will catch you off guard

I was suggesting differential tempering or drawing the temper at the back of a previously hardened blade not differential hardening, if the hot plate is showing a bit of colour it is more than hot enough for tempering a blade, we only need to take it to 240c or so.

 

[Shinken]

I was suggesting differential tempering or drawing the temper at the back of a previously hardened blade not differential hardening, if the hot plate is showing a bit of colour it is more than hot enough for tempering a blade, we only need to take it to 240c or so.

Sorry mate i was referring to soft back draw also, why i said differential tempering i have no idea. long day.

I am not criticizing the approach. It is sound in theory, just experience teaches me to be doubtful about it.

If you dont get it hot enough locally to the spine, the whole blade will just temper at the same time without the back becoming soft enough to be as strong as it could. ie the whole thing will temper to a similar hardness, where you want a bigger difference in rockwel from the spine to the edge

 

[Shinken]

Sorry mate i was referring to soft back draw also, why i said differential tempering i have no idea. long day.

I mean why i said dif hardening i have no idea. lol