Abstract: A tack fastener temporarily holds two or more parts together. An elongate tubular body of the tack fastener includes a longitudinal center cavity formed therein along a longitudinal center axis. A threaded hub is provided at a first end of the body and a plurality of tangs at a second end. Each of the tangs includes an enlarged tip having an inner shoulder that lies orthogonal to the longitudinal center axis. Each of the tangs has an outer surface which tapers inwardly toward the longitudinal axis in a direction toward the tip. A compression nut is mounted on the threaded hub. A stem is slidably mounted in the longitudinal center cavity. The stem includes a cone-shaped spreader with a distal end and having a contact surface with a gradually enlarging diameter in a direction toward the distal end. The spreader is movable between a position out of alignment with and a position in alignment with the enlarged tips.

Abstract: A tack fastener comprising an elongate, tubular body (51), a stem (53) slidable in the body and a compression nut (91) is disclosed. The body (51) has an enlarged threaded hub (55) at one end, which supports the compression nut (91). The other end of the body is slit longitudinally to create a plurality of tangs (57)--preferably four. The tips (61) of the tangs (57) are enlarged and include an inner shoulder (63) that lies orthogonal to the axis of the body (51). The tangs (57) are heat treated to cause them to converge toward one another, resulting in the diameter of the enlarged tang tips (61) being the same or less than the diameter of the main part of the elongate, tubular body (51). When the slidable stem (53) is slid into the body (51), it forces the tangs (57) outwardly, positioning the tang shoulders (63) to impinge on the blind side of parts (105, 107) to be tack fastened together.

Abstract: A semi-automatic track drill for use in drilling fastener holes for an aircraft body includes a pair of generally spaced, parallel rails. A plurality of slider bars extend between the rails and are connected thereto in a manner so that each bar can be slid along the length of the rails. Positioned between at least two of the bars is a drill carriage which is also slidably connected to the rails. A template having a series of alternating lands and grooves registers the carriage at preselected drilling positions. The drill assembly, including the template, is secured to the aircraft body by temporary clamping bolts which are positioned in a line along the body's surface.