Abstract: An automatic threading device, applicable to engine lathes or turret lathes, operating with a single point tool traveling parallel to the longitudinal axis of the lathe in a series of passes, generating the thread on a workpiece by synchronizing the travel of the device with the turning of the lathe, as in ordinary lathe threading, but in fully automatic sequences, reducing threading time to a few percent of that of conventional methods. A wide range of diameters, lengths, and thread pitches can be accommodated by one device. Except for a drive screw which provides longitudinal movement of the tool, all operating functions are pneumatically controlled. The device may be adapted for either temporary or semi-permanent attachment to a lathe.