Abstract: The size of the spiral gaskets which are formed by winding a sealing strip and a compressible filler strip around a mandrel is controlled by measuring the angle through which the mandrel turns, e.g., by means of an encoder. The lengths of arcs on the periphery of the gasket as it is wound around the mandrel are also measured, e.g., by means of a wheel running on the periphery of the gasket and an encoder counting turns of the wheel. The arcs are defined by the angles through which the mandrel turns. The supply of strip is terminated, e.g., by cutting the strips, as result of an arc achieving a particular length.