Abstract: In a false twisting apparatus in which the yarn to be twisted passes between parallel, rotating shafts carrying axially spaced friction disks which radially overlap disks on the other shafts, the yarn-engaging circumferential faces of the disks are surfaces of rotation about the shaft axes and arcuately connect respective radially extending, axially spaced end faces of the disks, each face having a yarn feed region and a yarn delivery region, the regions being annular about the axis of rotation and axially juxtaposed, the yarn feed region consisting essentially of aluminum, zirconium, or titanium oxide and having a surface roughness greater than the surface roughness of the yarn delivery region.