Shaft mounted gearboxes are hollow output bore designs that slide directly onto the driven machine shaft - the conveyor tail pulley shaft, bucket elevator head shaft, or aggregate conveyor shaft - and are fixed in position using a torque arm bracket connected to the machine frame. This direct mounting arrangement eliminates the separate output coupling, shaft keyway, base plate, and precision shaft alignment that conventional foot-mounted gearboxes require. The elimination of couplings, base plates, and alignment procedures reduces installation time significantly, particularly on equipment spread across large plant areas. The shaft-mounted design keeps drive weight concentrated at the driven shaft rather than requiring additional supporting structure, simplifying machine design and reducing fabrication cost. Torque arm attachment points on the gearbox housing connect to the frame with a pin or rubber buffer - providing torsional restraint while accommodating slight frame deflection. Shaft mounted gearboxes are available with helical gear trains (highest efficiency, smooth operation) and worm gear trains (high ratio, self-locking). Bore sizes cover standard conveyor shaft diameters from 25mm to 150mm. Shrink disc or keyway shaft attachment variants accommodate different shaft tolerance requirements. Shaft mounted gearboxes are the standard drive for belt conveyor tail and head pulleys, chain conveyor sprocket shafts, bucket elevator head sprockets, screw conveyor drives, grain handling equipment, and aggregate plant drives. The installation advantages are most significant in long conveyor installations where many drives must be installed and maintained along the length of the conveying system.