I made a double ended chuck key to fit both of my chucks a few minutes ago
and I'd like to case harden the square drive ends. The steel I used is
12L14 because that is what I had on hand.

I have some new formulation Kasenite and access to an OA torch. I understand
a carburizing flame can harden mild steel and of course so can Kasenite.

Which would be the better choice?

Thanks,

Wes

Wes,

As a not too WAG, I'd say Kasenite would be the way to go. You are applying carbonaceous material
as well as the carburizing flame of the torch. You should be able to do this with an ordinary
propane, or MAPP gas torch if you don't have ready access to acet..

Bob Swinney
"Wes" wrote in message ...
I made a double ended chuck key to fit both of my chucks a few minutes ago
and I'd like to case harden the square drive ends. The steel I used is
12L14 because that is what I had on hand.

I have some new formulation Kasenite and access to an OA torch. I understand
a carburizing flame can harden mild steel and of course so can Kasenite.

Which would be the better choice?

Thanks,

Wes

IIRC it takes a while to get the carbon into the part. We used to put
about a 0.020 case on millions of bolts and it took about 1 1/2 hours in
a furnace with a high carbon atmosphere, I think. I doubt if you'd do
much good with the torch because you'd still be oxidixing the part as
you go. Read the label on the Kasenite.
All you can do is to get a 20 thou or so case on the part. That
isn't what you need for the chuck key. You have chosen about the
softest steel one can find. I'd suspect that the problem will be
twisting the business end anyway and the case won't help much if you do
get it.

Pete Stanaitis
----------------------------------

Wes wrote:
I made a double ended chuck key to fit both of my chucks a few minutes ago
and I'd like to case harden the square drive ends. The steel I used is
12L14 because that is what I had on hand.

I have some new formulation Kasenite and access to an OA torch. I understand
a carburizing flame can harden mild steel and of course so can Kasenite.

Which would be the better choice?

Thanks,

Wes

On Wed, 08 Aug 2007 10:06:14 -0400, Wes wrote:

I made a double ended chuck key to fit both of my chucks a few minutes ago
and I'd like to case harden the square drive ends. The steel I used is
12L14 because that is what I had on hand.

I have some new formulation Kasenite and access to an OA torch. I understand
a carburizing flame can harden mild steel and of course so can Kasenite.

Which would be the better choice?

Thanks,

Wes


Hey Wes,

I would bow to Bob Swinney and Pete Stanaitis on the issue of which
method is easier/best, but it has been my understanding that while
12L14 is wonderful to machine (especially to "turn"), it will always
be a "soft" metal due to it's metallurgic composition.

I would think that now that you have had the practice of making this
neat sounding gadget (PICTURES PLEASE!!!) that if you just remake the
same thing but using drill rod, you'd have a better chance, and easier
than case-hardening too.

Take care.

Brian Lawson,
Bothwell, Ontario.

I have some new formulation Kasenite and access to an OA torch. I
understand

My Kasenite method is dead easy. heat part red hot, dip in kaesnite can, let
cool. Repeat as often as you want- case harden goes deeper each time. Last
time you heat, dip in water instead to quench and harden.

Karl

Wes wrote:

I have some new formulation Kasenite and access to an OA torch. I
understand a carburizing flame can harden mild steel and of course so can
Kasenite.

You'll fail with just the flame. Heat to red, dip in Kasenit and hold the
heat for some minutes. Directly quench and don't temper. Yes, I know, it
should be done different!
Works good enough for what you need. I hardened the head of a self-made
screw (out of free cutting steel) that way years ago and it still is good
enough (no more perfect, but it is used often).

Nick

Brian Lawson wrote:

I would bow to Bob Swinney and Pete Stanaitis on the issue of which
method is easier/best, but it has been my understanding that while
12L14 is wonderful to machine (especially to "turn"), it will always
be a "soft" metal due to it's metallurgic composition.

Now I am a bit confused. I looked up the properties of 12L14 and 4140

http://kmac-distribution.com/technic...-stainless.htm
11600 ksi shear modulus

http://kmac-distribution.com/technical/4140-Steel.htm
11600 ksi shear modulus

IIRC from my junior college days mild steel has about 60,000 psi shear so
this modulus number must mean something else. I googled a bit but didn't
really understand the explainations.

Given the typical length of a chuck key handle, I don't think I'm going to
twist the end off.

Wes

Shear modulus refers to stiffness, not to strength. The shear, tensile, and
compressive moduli for all steels fall in a very narrow range relative to
each other, regardless of their strength or hardness. Stainless is somewhat
lower.

The tensile yield strengths of the two materials are 60.2 kpsi for 12L14 and
143 kpsi for 4140, respectively -- at the respective Brinell hardness tested
by your website source, anyway.

The softness or hardness of a steel grade generally relates closely to its
strength. In this case, the hardness of the 12L14 reported on your site is
163 Brinell, versus 311 Brinell for the 4140. This actually varies over
quite a long range in the case of 4140, depending on heat treatment. But
that's about it for 12L14, unless it's carburized and heat-treated.

I don't know if 12L14 can be carburized successfully, in any case. The
question has come up here before but I forget the answer.

I haven't read this thread but 12L14 is not a good choice if you need more
strength than that of mild steel. Case-carburizing with a reducing flame is
not going to give you a thick enough case to add any significant strength,
regardless of whether 12L14 can be carburized. You could do it with Kasenit,
perhaps, using a pack-hardening method in a clay, stainless-foil, or
tin-can-steel pack, in a furnace of some kind. But Kasenit is really for
surface hardening for wear-resistance, not for the kind of deep
case-hardening sometimes used in industry for increasing strength.

--
Ed Huntress


"Wes" wrote in message
...
Brian Lawson wrote:

I would bow to Bob Swinney and Pete Stanaitis on the issue of which
method is easier/best, but it has been my understanding that while
12L14 is wonderful to machine (especially to "turn"), it will always
be a "soft" metal due to it's metallurgic composition.

Now I am a bit confused. I looked up the properties of 12L14 and 4140

http://kmac-distribution.com/technic...-stainless.htm
11600 ksi shear modulus

http://kmac-distribution.com/technical/4140-Steel.htm
11600 ksi shear modulus

IIRC from my junior college days mild steel has about 60,000 psi shear so
this modulus number must mean something else. I googled a bit but didn't
really understand the explainations.

Given the typical length of a chuck key handle, I don't think I'm going to
twist the end off.

Wes

Wes, I read the thread and I see you're just trying to harden the drive
ends. You can do that with Kasenit, using one of the methods others have
described here. As Nick says, just quench, don't temper.

You'll still want a pretty good case. You'll want to repeat at least two or
three times (only quench on the final treatment), as someone else suggested.
Getting a case thicker that 0.005" or so with Kasenit generally requires
pack-hardening. But 5 thousanths ought to do it OK.

--
Ed Huntress

Wes,

12L14 readily takes case hardening, however to reach maximum case depth
requires packing in Kasenit & soaking in a heat treat oven for up to one
hour (.030 case depth) at 1600 degrees. Merely heating the part with a torch
and dipping will only provide a superficial case depth. I have even less
confidence in using only a carburizing torch flame.

However I would question the need to even harden a chuck key, I never felt
the need to do harden my shop made keys, and I have milled factory keys to
adapt and those were soft too.

Tony

"Wes" wrote in message
...
I made a double ended chuck key to fit both of my chucks a few minutes ago
and I'd like to case harden the square drive ends. The steel I used is
12L14 because that is what I had on hand.

I have some new formulation Kasenite and access to an OA torch. I
understand
a carburizing flame can harden mild steel and of course so can Kasenite.

Which would be the better choice?

Thanks,

Wes

I agree with everything that has been written here about hardening the
chuck key, but why do you want to harden it at all? I would much
rather my chuck key get all worn out than the sockets in the chuck.
If the chuck key is harder than the socket guess which one is going to
wear out.

On Aug 8, 7:29 pm, "Tony" wrote:


However I would question the need to even harden a chuck key, I never felt
the need to do harden my shop made keys, and I have milled factory keys to
adapt and those were soft too.

Tony

"Wes" wrote in message

...

On Wed, 8 Aug 2007 21:29:27 -0400, "Tony" wrote:

Wes,

12L14 readily takes case hardening, however to reach maximum case depth
requires packing in Kasenit & soaking in a heat treat oven for up to one
hour (.030 case depth) at 1600 degrees. Merely heating the part with a torch
and dipping will only provide a superficial case depth. I have even less
confidence in using only a carburizing torch flame.


The tap wrench I made as an apprentice that was hardened by heating, dipping
and heating is still good after thirty years :-)


Mark Rand
RTFM