Abstract: In a friction false-twisting unit including three parallel spindles supported on a mount and each spindle carrying a stack of friction disks and the friction disks of the various spindles being interleaved, the thread to be threaded into the unit passing from an upper thread guide above the ends of the spindles, over a thread guide arm which holds the thread away from contact with the disks, and to a feeder system below the other end of the spindles. A support lever is movable between an operative position which holds the drive whorl for the spindles in contact with an operating belt and an inoperative position at which the spindle mount is moved to separate the drive whorl from the belt. The thread guide arm is on the support lever to be moved to the position holding the thread away from the disk when the support lever is moved to the inoperative position of the unit.