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.
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer firstname.lastname@example.org
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 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 :)
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
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
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
Yeah, a cooling press for a quench is probably not gonna be too dependable
unless you're talking about really flat thin stuff.
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?
Here is an email I saved from TheForge. I save many of Hochewa's posts.
Quenchants are to extract heat from the work piece at somewhat of a controlled
The traditionally meanest, fastest, ugliest quench was sodium hydroxide (lye)
in water to the tune of about 10% by weight. Lye is dangerous as it will chew
on your skin, eyes and lungs.
The action of the sodium is reportedly to reduce the solubility of air in the
water. Less air, more water better quench.
The action of the salt is to deposit itself on the work piece as the water
evaporates around the work. The resulting steam blanket is a poor quench
medium. The salt that precipitates onto the surface has some water of
hydration in it. As it heats, it turns to steam rapidly (I want to say
explosively here but it is not an explosion). This burst of steam breaks down
the steam blanket surrounding the work and fresh quench is brought to the
surface. The process repeats itself until the work is below 212*F. This is
the sizzle that you hear. The formation of steam on the surface of the work
extracts a most of the heat. The water does not do much until the work is
cool enough that you are not making steam. Then the water cools by conduction.
Common salt in water to the tune of 10% by weight works exactly the same way,
almost as well and is a lot safer. The old timers say the brine should be
strong enough to float a potato. More salt is not better.
Plain water is not a good quenchant as the chemistry of it is variable. Just
imagine what has lived or died or fallen into your slack tub.
MIneral oils can be had in a variety of quench rates. Synthetic quenchants
are glycol based and can mirror the mineral oils without the flamability
worrys. Motor oils are usually too thick to be effective but they can be used
in a pinch.
Gunter's Super Quench is an attempt to maximize the quench rate without the
hazards of lye. The principles are the same. The major difference is that
the SQ contains surfactants and detergents which are wetting agents. It still
contains water and salt. The wetting agents probably do the most good as the
work cools to below the flash point of water.
Given all of the above, why do you have to worry about quench rates?
A full explanation of a TTT-Curve is beyond my patience at this point in time.
A brief summary follows:
The ttt curve is shaped like a C. The y axis is temperature and the x axis is
time. The nose of the C is at or about 1200*f or so. The distance between
the y axis at t=0 and the nose of the curve is determined by the alloy content
of the work. This also determines the quench. If you go through the nose of
the curve you make pearlite. Miss the nose and you have a shot at martensite.
For a 1% plain carbon steel like W-1, the distance between the nose of the
curve and the y axis is about 1-2 seconds. This means that you must take the
work from 1575*F of so to 1200*F in less than 2 seconds. This is why you use
brine and this is why it only hardens to a limited depth. For A-2 this time
is about 2-3 hours. A-2 is air-hardening. It also hardens all the way
Hardening does not occur until you cool the piece to around 400*F. But then
this is another story.....
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.