proceed, depending on the goal
desired. These are simple: attrac-
tiveness or true-to-original colors
on vintage restorations. Here there
is trial and error. Al feels that the
mixture of wood and bone used
for packing is a major factor in
the process, but not the only one.
He has settled on one part bone
to two parts wood for some action
types such as leverguns or single
shots, but he uses one part bone
to four parts wood on Parker or
L.C. Smith shotguns. Contributing
factors to coloring results include
the temperature of the parts when
quenched – a sure indication of the
parts being too cool is a gray ap-
pearance instead of colored. On
the other hand, if heated too long
they can end up brittle.
Al uses two sizes of rectangu-
lar crucibles. The large one for
receivers is 3.5x5x12 inches. For
smaller parts he uses one measur-
ing 4.5x5x9 inches. Al’s experience
is that parts must be surrounded
by .75 to one inch of the bone/
wood mix between parts and the
crucible walls. And there needs
to be 2 inches of the mix on top
because it can settle during heat-
ing, and any exposed steel will end
up with “scale” instead of colors.
Here’s something I found interest-
ing: Al says the parts or actions
should be heated with the heavy
end upward, for if they enter the
water quench flat there is a great
chance they will warp. Finally, the
last step before heating is to seal
the crucible with fire clay to keep
oxygen out.
At this point in Al’s narrative, I
was starting to feel that color case
hardening was easy; just grab a
furnace, some sort of crucible and
order bone/wood mixes from a
gunsmith supply company. But Al
wasn’t finished by a long stretch.
He emphasized strongly that
if you don’t have the ability to
“tweak” parts or actions back to
original dimensions, then don’t
take up coloring case hardening.
Actions and parts can be blocked
perfectly, but the transition from
over 1,300 degrees to less than
50 degrees during quenching is a
sudden jolt to steel. Before start-
ing the process, Al takes measure-
ments of all items. Then after the
process he measures again, which
is where the know-how to “tweak”
i s nece s sa r y.
For blocking, Al takes two
routes. First, the item is blocked
to prevent warping as mentioned
in the above paragraph. He puts
blocks between the bolt rails on
leverguns and also between upper
and lower tangs. For box-lock and
side-lock shotguns, he uses blocks
between the tangs. It is Al’s opin-
ion that blocking can be overdone- too much and the block might
warp, and that means the part
goes with it.
This next factor also surprised
me. Al said that even though
superheated to 1,375 degrees,
smaller steel parts start to cool
instantly when moved from the
crucible. If allowed to cool very
much, colors become milky gray.
With larger items such as actions.
He feels that 1,300 degrees going
in the quench is still acceptable.
To help maintain those tempera-
tures, Al blocks every part by plac-
ing a .25x2x6-inch piece of strap
iron against all four walls of the
crucible. He puts a piece of strap
on either side of a lever. The pur-
pose of these straps is to prevent
parts from cooling between the
furnace and quench.
The quench itself is not as sim-
ple as dropping the whole shebang
into a bucket of water. A 5-gallon
container is used for small parts
and a 20-gallon container is used
for actions, and he only fills them
with distilled water. Before parts
are quenched, both tanks are aer-
ated for 15 minutes. Al leaves the
aeration running for small parts
but turns it off prior to quenching
actions. He has found that the air
running continuously on actions
makes microscopic pitting on flat
surfaces. Inside the 5-gallon wa-
ter container, Al has a screen for
parts to land on, but with actions
he has a chain welded to the inside
bottom of the crucible so that the
action drops to a predetermined
depth. His final operation is to
stress relieve all parts and actions.
After visiting with Al and get-
ting his ins and outs of color case
hardening, I see why every gun-
smith doesn’t offer it as an option.
It is definitely an art.July-August 2019 http://www.riflemagazine.com 17
This is how a rifle lever is blocked
during the pack-hardening process.A piece of chain is used
to hold a rifle or shotgun
receiver in the water
quench so that it touches
nothing as it cools.R