Forge Work

by William L. Ilgen

Drawing with the top and bottom fullers, in the manner shown with the swages ([Fig. 32]), ought to be done cautiously, as the metal decreases in size so rapidly that there is danger of its becoming too small at the fullered place before the operator is aware of it. When using the top fuller alone, in the same manner as the flatter ([Fig. 33]), similar precautions should be observed. If the metal is to be decreased between two shoulders, the top fuller may be used to rough it out; but the fuller marks should be distributed between the shoulders, until one of the set hammers or the flatter can be used.

If the metal is being drawn and is held crosswise on the anvil, as shown at a, [Fig. 34], it will increase in length more rapidly than it will in width, and if held lengthwise as at b, it will increase more in width than in length. This is due to the fact that the anvil is slightly convex on its face, so that it has the effect of a large fuller.

Fig. 34.—Drawing with the Hand Hammer.

The most difficult drawing for the beginner is to form metal into a square or hexagonal shape. To draw it into a square form, the metal must always be turned either one quarter or one half of a revolution to prevent its becoming diamond-shaped, and the blows must be delivered equally on the four sides to prevent its becoming oblong. If it does become diamond-shaped, it can be made square by delivering blows at a slight angle on the corners and sides of its long diagonal as shown at A, B, and C, [Fig. 35]. If it is but slightly diamond-shaped, the method shown at B will prove satisfactory, but if badly out of square, the method at A will be the best.

Fig. 35.—Squaring up a Diamond-shaped Piece.

In drawing the hexagonal form, the metal should be turned by sixths of a revolution. If it becomes distorted, it may be forged with such blows as are shown at B and C; if held as at A, it would be marred by the edge e.

54. Bending is the operation of deflecting metal from a straight line or changing its form by increasing the deflection already present. Iron of any cross-sectional shape can be bent, but some shapes are much more difficult than others.

The easiest to bend is the round, the only difficulty being to prevent the hammer blows from showing. If the metal is to be round in section when finished, the work will not have a good appearance if the cross section is oval at some places and round at others, and unless the hammer blows are cautiously delivered this will be the result.