Temporarily weld several separate pieces of scrap on to the bar until sufficient metal is provided for a thorough welding and forging of a solid piece of square iron 31⁄2 inches long and 11⁄16 inch square. The welding should be done so as not to show where the pieces were joined. Forge it perfectly square and smooth with the flatter. Cut one end off square with a sharp hot cutter, then cut it to the required length.
77. Round Weld.—[Fig. 57]. Scarfing, welding, and swaging. Material required: two pieces of 7⁄16-inch round iron, 41⁄2 inches long.
Upset one end to 9⁄16 inch, as shown at a. To form the scarf, deliver backing-up blows with the face of the hammer, as shown at b, and finish with blows delivered similarly with the ball. These backing-up blows will form the heel of the scarf. Draw out the point of the scarf with overhanging blows, as shown at c. The joining surface should be convex so that welding will proceed from the center. Scarf both pieces in the same manner, as at d.
Fig. 57.—Steps in Scarfing for a Round Weld.
Heat and weld according to instructions on welding and finish the work smoothly with swages; then cut to a length of 6 inches, having the weld in the center.
Properly formed scarfs will produce perfect welds provided they are heated to the welding temperature when they are joined, but those improperly formed generally produce imperfect welds, although the heat is right.
78. Flat Right-angled Weld.—[Fig. 58]. Material required: two pieces of iron 3⁄4 × 3⁄8, 41⁄2 inches long.
Upset one end 1⁄8 inch larger than its diameters, as at a. By using backing-up blows as in the previous exercise, form a heel on one side, as shown at b, then resting the straight side on the anvil, draw out the point with the ball of the hammer, as at c. In drawing this point, the metal will spread and form a wide fan-shaped end, but by resting the right side d on the horn of the anvil and delivering blows on the left, the latter edge will be straightened, leaving all projecting metal on the right.
