A discussion on friction - Friction between single fibres

Single textile fibres are of the order of magnitude of 10 to 50μ in thickness. The measurement of friction between them in a longitudinal direction therefore offers some experimental difficulties. Two forms of apparatus have been designed. One measures the friction between two fibres crossed at a small angle. The second one measures the friction in a twist of two fibres. It has been found by both methods that the dependence of the frictional coefficient on the normal load is considerable. With increasing load the coefficient decreases. For the study of the nature of friction the small dimensions of the fibres might become very useful. Two crossing fibres with cylindrical cross-sections give a well-defined contact, which is difficult to obtain with plane surfaces. The almost parallel cylinders (twist method) give in the ideal case a well-defined line-contact.