A pipe machining apparatus includes a frame, a tool support mounted on a tool carrier which is mounted on the frame, and a gearing arrangement for rotating the frame, and a motor for rotating the gearing arrangement. The gearing arrangement includes a toothed pinion gear, a toothed backlash adjustment gear which is moveable relative to the pinion gear and being capable of being fixed in position relative to the pinion gear by a locking assembly, and a toothed bull gear affixed to the tool carrier. The teeth of the bull gear are capable of being engaged with the teeth of the pinion gear and with the teeth of the backlash adjustment gear, the bull gear to minimize backlash.