Construction Hints

Radio Record, Volume III, Issue 28, 24 January 1930, Page 27

Construction Hints

A Tapping Hint. F you have a considerable number of holes to tap in a piece of ebonite, don’t bother about the ordinary tap holder. Drill all holes, first of all, to the proper size, then mount the tap in the chuck of the hand-drill. Don’t try to drive the tap through "in one." Taking care to see that you are going straight, give it one turn or a little more, then turn backwards to allow the tap to clear itself of dust. Now go forwards again fora few turns, turn back to clear once more, and then drive straight through. With the hand-drill one can easily tap three or four 4 B.A, holes ‘in a minute-in }in. ebonite. A Useful Coil Rzck. XPERIMENTERS who are cone stantly changing coils of the plug and socket variety will find it very convenient to buy from any hardware shop a cheap wooden towel airer of the kind which screws on the wall and has three or four pivoted arms. One of these arms can be used for carrying aerial coils, another for short-wave coils, and a third, coils for the longe. wave band, while if there is a fourth, centre-tapped coils can be kept separs ately. Such a device, screwed to the wall above the experimenter’s_ table, not only saves a great deal of room but greatly facilitates work. on 1