Abstract: A variable speed and direction power transmission attachment for driving the cutting tool carriage of a lathe or the like, the attachment having sets of intermeshing male and female cog gears. Certain of such sets each comprises a face gear having a plurality of concentric rows of tooth socket elements formed therein. A male cog gear is selectively settable to mesh with any of such rows to change the gear ratio. By changing the combined setting of different sets of gears, a wide variation in overall gear ratio may be obtained to provide many different feeding speeds of the carriage, suitable for general cutting and for screw thread cutting. A reversing mechanism, also constructed of intermeshing cog gears, enables the direction of drive to be reversed or the drive to be disconnected to permit manual drive of the carriage.