Automated collar and nut installation requires complex hardware on the wet side of the spar or wing panel. Wet side automatic tool changers are becoming common but an operator is often required to connect electrical, pneumatic and fastener feed system components. This is unacceptable in a lights-out cell, and any fully automatic solution must be reliable while satisfying demanding design requirements. Figure 1Wet side anvil for nut installation.The 737 Spar Assembly Line (SAL) is a new lights-out machine cell at the Boeing factory in Renton, Washington. The SAL machines are equipped with a unique fully automatic tool changer (ATC). The wet side ATC interface is designed to automatically connect conventional as well as more unique services such as fastener feed. The fastener feed ATC module, called the “spinner,” rotates with the machine’s wet side rotary axis (C axis). It consists of a stack of rotors that rotate inside of a stationary annulus. Each rotor is designed for a size and type of fastener. Air conveys fasteners along the inner diameter of the annulus, requiring that each rotor is sealed from the others against the inner diameter of the stator. Nuts and collars are fed into their respective rotors, roll along the interior diameter of the annulus, and are redirected out of the annulus by a scoop fixed to the machine C axis. The scoop delivers the fastener to an anvil-mounted assembly which receives the fastener and blows it to the tool point for installation.