_Stock:_ Spring steel, 7/8 × 1/16 in. × 9 ins. long.
[Illustration: Butcher knife detail]
The spring steel used for carving knives or any steel used for that
purpose should be a grade that will harden in oil just hard enough to
feel a mill-cut file cut the steel. Cut the stock off 9 ins. and forge
the shank first. On this size steel this forging of the shank consists
in reducing the thickness of the material and widening it about 1/16
in. to 2 ins. in length. This tends to toughen the steel, and it makes
a better knife by this extra work.
[Illustration: Butcher knives]
To forge the blade, heat 7 ins. and bend it a little edgewise before
reducing the one side for cutting edge. Allow the stretching and
thinning out of this edge to straighten the blade, and the curve on the
back will form itself, naturally, by the extra length of the cutting
edge. Do not try to forge the exact shape of the knife. It is much
better to reduce it to the required thickness, outline the shape, and
cut it with a hot or cold chisel. At this thickness the knife can be
worked either hot or cold when doing this particular kind of work.
Cut along the outline, thus giving it shape. A fine file will finish
the roughness on the outline and trim up any uneven spots caused by
the shaping. When the knife is finished, so far as the forging is
concerned, anneal it by heating the whole blade and allowing it to
cool in slaked lime. This relieves any strain due to forging. Handles
are made of bone, birch, or beech, and can be shaped to suit one's
taste. They should measure about 1 × 5/8 × 5 ins. Rivets hold them in
place. (See cut.) These are of brass wire, easily made by cutting off
the length required to go through the wood to hold the blade in place.
Place the blade in the slot of the wood handle and drill four holes
through the wood and through the blade. Do not make the holes more
than 1/16 in. in diameter. Take the blade out, harden, and temper.
All drilling of holes and fitting should be done before the blade is
tempered, while it is in the soft state. It is difficult to drill the
holes after the tempering has been done.
_To temper the blade:_ The blade is tempered by heating it on a coke
fire. Place the back of the blade down, on a piece of flat iron. The
iron will heat red hot. The iron under the knife prevents the flame
striking the blade and heating it unevenly, in spots, as it were. When
the blade is red hot plunge it into a bath made of linseed oil. Take
it out of the oil and polish it. Use the piece of iron the blade was
heated on to draw the temper. This hot iron is put on the anvil, the
back of the knife edgewise is placed on the iron and moved forward and
backward to insure a uniform heat. As soon as the straw colour appears
take out any buckle or bend caused by the hardening. Place the other
side of the blade on the anvil. A few quick, sharp blows with the peen
of the hammer will straighten the blade. Continue the tempering until
the purple colour shows. The blade should be tempered so that a very
smooth, sharp file will just cut it when rubbed over the surface. Place
the blade in the handle and rivet it in place, polish it, and then
grind.