Manufacture of coils from plastic-covered wires by drawing over the sharp edge e.g. of a paper knife while exerting pressure with the thumb

摘要

The procedure consists of taking a section of straight plastic-covered metal wire (1, 3, 4) no more than 1 mm in diameter and drawing it across the sharp edge of an instrument such as a paper knife while exerting pressure on it with the thumb. The different levels of resistance to traction in the plastic and wires causes them to emerge in spirals with a spacing and regularity that depends on the pressure applied and the speed of drawing.