Fig. 13.
41. To Make Holes in Sheet-Metal. Fig. 13. Holes may be punched in sheet-tin, copper, zinc, etc., in the following manner: Set a block of hard wood, W, on end; that is, place it so that you will pound directly against the end of the grain. Lay the metal, T, to be punched, upon this, and use a flat-ended punch. A sharp blow upon a good punch with a hammer will make a fairly clean hole; that is, it will cut out a piece of metal, and push it down into the wood. A sharp-pointed punch will merely push the metal aside, and leave a very ragged edge to the hole. A punch may be made of a nail by filing its end flat.
42. To Punch Holes through Thick Yokes, etc. As soon as 5 or 6 layers are to be punched at one operation, the process becomes a little more difficult than that given in [App. 26]. If you have an anvil, you can place the yoke over one of the round holes in it, and punch the tin right down into the hole, the ragged edges being afterward filed off. Hold the yoke as in [App. 79] or [80] for filing. As you will probably have no anvil, lay an old nut from a bolt upon the end of the block of wood ([App. 26]), place the metal to be punched over the hole, and imagine that you have an anvil. Very good results may be obtained by this method. The size of nut used will depend upon the size of hole wanted.
43. To Straighten Wires. It is often necessary to have short lengths of wires straight, where they are to be made into bundles, etc. To straighten them, lay one or two at a time upon a perfectly flat surface, place a flat piece of board upon them, then roll them back and forth between the two. The upper board should be pressed down upon the wires while rolling them. If properly done, the wires can be quickly made as straight as needles.
44. Push-Buttons. Nearly every house has use for one or more push-buttons. The simple act of pressing your finger upon a movable button, or knob, may ring a bell a mile away, or do some other equally wonderful thing.
45. Push-Button. Fig. 14. This is made quickly, and may be easily fastened to the window or door-casing. One wire is joined to A and the other to C. B is a strip of tin or other metal, about ⅝ in. wide and 2 in. long. It is bent so that it will not touch A unless it is pressed down. This may be placed anywhere, in an electric-bell circuit or other open circuit, where it is desired to let the current pass for a moment only at a time.