Abstract: A self-drilling/self-tapping fastener which is suitable for attaching a sprinkler system to a metal supporting structure has a driving head and an integral shank with a threaded portion. Process-hardening and threading of the shank harden the shank to a degree of hardness that retains sufficient ductility for resisting vibration loads. The drill tip at the end of the shank and the lead threads adjacent the drill tip are locally hardened to a relatively high degree of hardness for drilling and tapping the metal support members. A graduated transition zone separates the high-hardness zone from the lower-hardness zone, which allows for a single fastener to exhibit two distinctly different material properties in one fastener. The fastener through this dual process also exhibits two distinct load-carrying capabilities.

Abstract: A fastener assembly for anchoring masonry to a wall support stud includes a sealing member releasably seated in a retaining groove. The fastener threads into the support stud and is affixed to a hole in the masonry with a bonding agent. The retaining groove holds the sealing member in place during the installation of the fastener, and a break-off groove enables the fastener to be severed inside the masonry. After the fastener has been severed, the sealing member can be relocated inside the masonry to a pre-determined sealing position, thereby insuring the use of a controlled volume of bonding agent.