ISO 4817:1984

The directional stability (drift) is caused by irregularities of the feed mechanism as an individual machine funktion, without using a sewing thread. The method is applicable to motor-operated household sewing machines, but it may also be possible to apply it to hand- or treadle-operated machines. Includes additionally to definitions, principle, preparation of the sewing machine, prodcedure, expression of results and test report an annex which specifies material and apparatus.