Abstract: There is disclosed screw adapted to fasten two or more juxtaposed workpieces which comprises a threaded shank defining an axis and a major thread diameter. A drilling tip is provided which extends from the shank and includes a pair of cutting edges. Material removing extensions are formed continuously with the cutting edges and serve to extend the cutting edge in the radially outward direction at least as far as the radially outermost extent of the major thread diameter. The extensions are frangible and will fracture when a material of predetermined hardness is encountered. As such the fastener is adapted for drilling a first, enlarged bore in a first workpiece of relatively soft material, and a second smaller bore in a second workpiece of a harder material, such as metal, or the like.

Abstract: There is disclosed a fastener assembly comprised of a screw fastener member having a driver head, a threaded shank portion and an unthreaded shank portion intermediate the threaded shank portion and the driver head. The unthreaded shank portion also includes a protruding portion defining an effective diameter greater than the major diameter of the threaded portion. This portion is formed by rolling a groove into the unthreaded shank portion in such a manner as to provide an annular projection having a tapered surface portion. There is further included a helical compression spring member having at least one end portion formed to an inner diameter larger than the major thread diameter, but smaller than the diameter of the protruding portion of the unthreaded shank portion.