The Aeroplane Speaks. Fifth Edition

WIRES.--The following points should be carefully observed where wire is concerned: 1. Quality.--It must not be too hard or too soft. An easy practical way of learning to know the approximate quality of wire is as follows: Take three pieces, all of the same gauge, and each about a foot in length. One piece should be too soft, another too hard, and the third piece of the right quality. Fix them in a vice, about an inch apart and in a vertical position, and with the light from a window shining upon them. Burnish them if necessary, and you will see a band of light reflected from each wire. Now bend the wires over as far as possible and away from the light. Where the soft wire is concerned, it will squash out at the bend, and this will be indicated by the band of light, which will broaden at that point. In the case of the wire which is too hard, the band of light will broaden very little at the turn, but, if you look carefully, you will see some little roughness of surface. In the case of the wire of the right quality, the band of light may broaden a very little at the turn, but there will be no roughness of surface. By making this experiment two or three times one can soon learn to know really bad wire from good, and also learn to know the strength of hand necessary to bend the right quality.