Rotary and orbital sander

A rotary orbital sander including a motor housing enclosing a motor, a drive shaft rotatable by the motor, which drive shaft has an off-set projecting portion, a pinion gear housing affixed to the motor housing, a carrier supported upon the shaft off-set projecting portion by two parallel arranged ball bearings, a sanding pad assemblage removably attached to the carrier, intermeshing spur gears arranged on the pinion gear housing and the carrier, a handle arranged for conduction of pressurized pneumatic medium to the motor, a throttle valve for regulation of pneumatic medium flow to the motor, a valve in the handle for cut-off of pneumatic medium to the throttle value, and a counter-balance weight affixed to the shaft off-set projecting portion, said weight being positioned so that its center of gravity of rotation is in the same plane as the center of gravity of rotation of-the carrier, the carrier supporting bearings and a sanding pad assembly attached to the carrier-said pinion gear housing having a circular cavity surrounding the carrier which is engageable by the carrier as it revolves, to provide rotational support for the carrier.