A powered oscillating hand tool includes a drive unit having an electric motor and a drive shaft; a bearing eccentrically mounted on the drive shaft and located radially eccentrically relative to the drive shaft; a carrier plate mounted on the bearing and a platen for mounting on the carrier plate. The carrier plate is provided with a first engagement means and the platen is provided with second engagement means to engage with the first engagement means by rotation of the platen relative to the carrier plate. The first and second engagement means together comprise a bayonet fitting.