Each spindle is driven through an individual air clutch. Torque at each spindle is determined by separate, adjustable pressure reducing valves.
Clutches disengage before bits pull out of screw slot, thus avoiding marred screw heads.
A fast feeding, oscillating type multi-track feeder with self clearing gate is used to feed the screws. An air-operated escapement simultaneously releases screws to each driving station. Several standard designs available to meet practically all driving conditions. Chucks have accurately machined, hardened steel bodies and spring-tempered, stamped jaws which are stock items and easily replaced when worn.