quenching media ?

Now that brings up a good point. In order to harden a piece of steel you simply need to drop it through the nose curve in a short enough amount of time. Seems like really thin stuff would be darn near air hardening. I wouldn't think it would really be that difficult to stick thin stock knives between copper plates in the same time it takes to quench it and that should eliminate any warping.

GA

Have the copper plates in a wood vise. (or wood lined) Have a three sided box in sorts - two of copper - the bottom being whatever and under the copper. The copper is 'attached' to the wood plates so they don't fall. Take out the blank from the oven and place it top edge down and turn the handle.

The knife could be carried in a 'quiver' of insulation if the vise is far away.

That is an idea - just an idea, but one never knows.

Mart> Now that brings up a good point. In order to harden a piece of steel you

amount of

which begs some questions.

how thin would the knife have to be to quench between copper plates?

how thick would the copper have to be?

would chilling the plates help or cause problems?

would other types of metal plates work?

are these questions worth anything (i.e. will someone try this) or are they just theoritical?

Nothing wrong with theoretical. For instance, I'm mostly interested big blades with non flat geometry. No good to me at all. On the other hand if later I decide to make a small folder knife where I need a precisely flat blade then this could be quite handy... :-)

Industry uses that method sometimes. :) Betcha it's an expensive and carefully machined set up tho. :/

IMO, it ain't worth messing with because the warps can be straightened out, right after the quench.

I consider it part of the quenching process.

All the austenite doesn't decompose to martensite all at once, when first pulled from the quench tank the steel is mostly still soft (austenite) over the next few seconds it changes over so you have time to straighten it out.

I use clunky old line-pliers. ;)

It's tricky as anything for me, but I can see a guy getting really good at it. Yes, the dangged stuff is constantly changing... its stiffness and its elastic limit are both changing quickly, but only in one direction, and I believe at a predictable rate, something that can be counted on? If so, that's your foot-in-the-door.

I've failed to get a few longer blades right, but off-hand I don't think I've made any worse than if I'd left 'em as-is.

Those were 1095 too, something with a little Cr in it should be slower to transform, so allowing more time?

It's tricky, but so is riding a bicycle, just need more experience IMO and it could become second nature too?

Another reason I don't like the quenching between plates idea is you'd need at least an oil hardening steel to make up for the non-contact points (it isn't going to mate perfectly)... :/

A need for air hardening steel sounds more like it now huh? ;) Air hardening steel won't need plates to keep it straight. ;) Is that a Catch 22? :)

Part of my problem with fixing -all- my warped blades is I heat treat at night. :/ YMMV (your mileage will be better ;) since you won't be using line pliers and it won't be so stinkin dark either. ;)

Another thing is, I heat treat a batch like 1 to 3 times a year, I don't see myself ever getting real-good at taking advantage of this property.

I betcha most old time blacksmiths were friggin good at taking advantage of that property tho! Don't you think so too? :)

What do you think? :)

Alvin in AZ

Industry uses air hardening steels and/or "make it too big and finish grinding to size after heat treatment".

Alvin in AZ (read that in more than one ASM book;) ps- I am ASM's number-one newsgroup parrot :)

Hmmm - I think next time I set out to quench a blade I'm gonna keep my anvil handy along with my industrial strength flatter ;-) Got the piece of the railroad rail that I cut off the underside of my anvil. Basically the foot and webbing of the rail about 8 inches long. Keep it around to smack down on hot iron to surface level and straighten. Think if I just press a blade right out of the quench it will hold straight after a few seconds of further cooling? One of the things I did wrong with the last blade was to take it all the way to *cold* in the quench. Should have got it into the oven while it was still good and warm. I found a couple of small fractures in the edge later.

Yeah, a cooling press for a quench is probably not gonna be too dependable unless you're talking about really flat thin stuff.

GA

Hello everyone, I was just wondering. What would be the suspected results if I were to quench, in the mixture above, a blade made from a plain high carbon steel, such as one made from an old file?

Also, what effect would adding a bag of ice to the mix be?

Bear

Superquench is only useful for 40-50 points of carbon and below. If you put the above blade in, it would crack or shatter in the quench. Way too fast for real tool steel.

Steve