a hand - held endless belt abrading machine comprises a base portion and a main portion , which portion is rotatable relative to the base portion around an axis extending in a forward and rearward direction of the abrading machine . the main portion comprises an air motor having a rotational shaft extending in a direction transverse to the abrading machine and projecting from the left end of the air motor , so that an abrading endless belt assembly drivingly connected to the output shaft is positioned to the left relative to the motor and the base portion which is held by a hand of an operator . when a left - handed person uses the abrading machine , the main portion is turned 180 ° relative to the base portion to shift the abrading endless belt assembly to the right relative to the base portion , thereby enabling the operator to readily observe the abrading belt assembly in operation .