An adapter assembly is provided for selectively interconnecting a surgical end effector that is configured to perform a function and a surgical device that is configured to actuate the end effector, the end effector including at least one axially translatable drive member, and the surgical device including at least one rotatable drive shaft. The adapter assembly includes at least one drive converter assembly including a drive shaft； a drive coupling nut threadably connected to a distal end portion of the drive shaft； and an axially translatable drive bar connected to the drive coupling nut, wherein rotation of the drive shaft results in axial translation of the drive bar. The drive coupling nut engages 29 teeth of the threaded distal end portion of the drive shaft. The drive coupling nut is manufactured from unreinforced PEEK thermoplastic polymer.
