Abstract: In a non-slip rectilinear wiredrawing machine with tangentially uncoiling pstans, each capstan is composed of two concentric and coaxial parts, the first of which driven by a motor and comprising the typical capstan pulling face, the second part a freely-revolving ring affording a run-out from which the wire is drawn through a die by and onto a successive capstan; the speed of the individual capstans is synchronized by a device capable of monitoring both the angular movement of the shaft driving the first part of the capstan and the angular movement of the ring, detecting any difference between the two, and correcting the angular velocity of the shaft accordingly.