Abstract: A hand held machine tool intended for grinding and like operations, having an outer housing containing a pneumatic vane motor by which a tool carrying spindle is rotated. At its forward end, the motor is supported in the housing by at least one resilient O-ring for absorbing radial vibrations arising in the spindle during work and a conical thrust ball bearing for transferring axial load to the housing without restraining the radial resiliency provided by the at least one O-ring. At its rear end, the motor is supported in the housing by a substantially non-resilient O-ring, which means that the motor is apt to perform a pendular movement about its rear end when exposed to vibrations from the spindle.

Abstract: A rotary pneumatically powered tool comprising a housing, a motor assembly mounted in the housing and comprising a pneumatic motor for rotating an output shaft, and vibration absorbing mounting means for supporting and vibration insulating the motor assembly relative to the housing. The vibration absorbing means comprises a resilient connection piece for cramping the motor assembly axially in the housing and for interconnecting air passages in the motor assembly and the housing so as to enable communication of pressure air to and from the pneumatic motor of the motor assembly.