What is meant by forming? What other operations may be involved? What special tools or appliances are sometimes used for forming? State what has been said about straightening? Does it require much skill? Would it be as easy to straighten a wide flat piece of metal, as it would a round one? Why? Explain the operation of twisting. Why is it generally done? How can twisting be done and keep the work perfectly straight? Explain the essential parts of a weld. Is a weld as strong as the original unwelded bar? Can all iron and steel be welded? What kind of fire is best for heating? What is meant by an oxidizing fire? What effect does it have on the metal? How can an oxidizing fire be prevented? How should scarfs be placed in the fire? Why? If a penetrating and thorough heat is desired on a piece of metal, how can it be obtained? What is meant by scarfing? Are all scarfs formed alike? Name and describe the different kinds of scarfs and welds. Which one is considered the weakest? Why? On what kind of work is the V weld used?
=68. Staple.=—Fig. 48. Drawing and bending. Material required: 5 inches of 1/4-inch round iron.
[Illustration: FIG. 48.—STEPS IN MAKING A STAPLE.]
Draw 1 inch of each end to a flat chisel-shaped point 1/4 inch wide; these drawn ends should be 1-3/4 inches long, leaving 3 inches of round stock between them. Heat the center and bend it, with points edgewise, to a semicircle of 3/4 inch inside diameter. These ends should be of equal length, parallel and straight.
When drawing the ends, heat the metal to a white heat to prevent the fibers from splitting or separating. Heat only to a cherry red for bending, to prevent heavy scaling, which is one cause of rough-appearing work. Rough work may also be caused by improper use of the hammer in striking too hard or frequently at one place. (See Fig. 48 for dimensions and stages.)
=69. Draw Spike.=—Fig. 49. Bending and drawing. Material required: 7 inches of 1/4-inch round iron.
[Illustration: FIG. 49.—STEPS IN MAKING A DRAW SPIKE.]
Bend 3-1/4 inches of one end nearly to a right angle; have the inner corner almost sharp and square, the outer portion circular at the corner. Then form a perfectly circular eye of the 3-1/4-inch end, having the center of the eye in line with the central portion of the stem. When drawing the point, first draw it square, then octagonal, and then finish it to a round. (See Fig. 49 for dimensions and stages.)