In an output drive where a tool includes a rotating driver 24 having an offset finger cam 36, the offset finger cam engages a cam follower 40 which transforms rotary motion into oscillating motion. The cam follower is keyed to an output drive shaft 48 which in turn includes means for attaching a working tool such as a saw blade 22. The entire apparatus is contained in a housing 16 which attaches to a motor which may be pneumatic, electrical or fluid and a second section 60 which houses the cam follower and output drive shaft. The tool may be used to saw a cast on a patient. <IMAGE>
