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.
ORNAMENTAL IRON WORK
XXVIII
PROCESSES, ANDIRONS, FIRE TOOLS
The handling of wrought iron when making ornamental work often brings in, besides the usual smithing operations, the processes of embossing, impressing, engraving, etching, inlaying of copper or brass, grinding, and polishing. Embossing is done by heating the piece and raising the metal from the back into an iron above the surface.