A rotatable wrist connecting a gripper tool to the distal end of a positioning shaft. The rotatable wrist includes a wrist hub that is non-rotatably connected to the distal end of the shaft. A wrist capstan is rotatably connected to the wrist hub and non-rotatably connected to an actuatable device (e.g., a gripper). A flexible wire loop extends through the wrist hub and partially contacts the wrist capstan. Linear movement of the flexible wire loop through the shaft causes rotation of the wrist capstan due to friction between the flexible wire loop and the wrist capstan. The wrist also supports selective detachability and control of roll, pitch and roll, pitch yaw and roll according to different embodiments.
