Abstract: An orbital sander/grinder has on one side of its housing a rotatably mounted disk holder which is brought into orbital motion by means of a drive mechanism that is inside the housing, and is coupled with an eccenter. The eccenter is rotatably mounted on one side in the housing, on the other side in the disk holder, while the rotational axis in the housing is radially offset relative to the rotational axis of the eccenter in the disk holder, but the two axes run parallel to each other. A balancing weight for compensating the unbalance rotates in synchronization with the eccenter. To ensure sanding/grinding with a minimum of vibration, means are provided to compensate for the transverse forces generated by the abrasive and/or cutting forces that are exerted at the eccenter.