Abstract: An apparatus has a polishing head for polishing an object such as a semiconductor wafer by using a polishing tape stretched between two guide rollers. The head can be rotated so as to change the angle of contact between the tape and the object and also undergo a reciprocating motion perpendicular to the direction of supply of the tape. For this purpose, the apparatus includes a first plate attached to the head and a second plate supported parallel to each other and in motion-communicating relationship by means of rods which are attached to the first plate and penetrate the second plate. The second plate is attached to the rotary shaft of a direct drive motor for causing oscillatory angular motion. This rotary shaft is tubular and an inner shaft for causing the oscillatory motion passes slidably therethrough.

Abstract: A working tool has a large number of cutter rings (2.1 to 2.3) on a curved guide rod (1) of circular cross section. The guide yoke (1) exhibits at least two helical grooves winding in opposite directions along its outer side, the cutter rings engaging into these grooves in each case with at least one guide element. Consecutive cutter rings (2.1, 2.2) engage with their guide elements in each case into contrarotating grooves.