Abstract: Fastener installation apparatus for operating cyclically so as to instal successively a plurality of fasteners includes a fastener installation head (11) having an aperture (35) in which part of a fastener is inserted, and a vacuum generator (20) for creating an airflow in through the aperture (35), along a pipe (31) and into a receptacle (15) for broken-off fastener parts. The presence of a fastener in the aperture (35) causes a change in the level of vacuum in the pipe (31) and receptacle (15). The level of vacuum is sensed by vacuum level detection means (45), which gives an electrical signal to the apparatus control unit (14a, 14b). The control unit allows the installation apparatus to continue its cyclical operation only upon the presence or absence of fastener in the aperture (35) at the appropriate points in the cycle of operation of the apparatus.