Abstract: A self-drilling screw comprising a threaded shank having a head at one end and a forged drill bit at the other end, the drill bit including a pair of oppositely disposed intrusion faces and a pair of oppositely disposed axial flutes, a chisel edge formed at a lower extremity of the drill bit and divided into two parts by a downwardly projecting apex formed on the chisel edge, the two parts extending from the apex in the opposite directions and each being slightly inclined to provide an inclination angle formed between itself and a workpiece surface, the inclination angle being within the range from 5.degree. to 20.degree., the drill bit further including a pair of oppositely disposed vertical flat rake faces which substantially adjoin each other at an adjoining point disposed on the chisel edge and which extend upwardly from the chisel edge in a vertical plane substantially containing the chisel edge and a longitudinal axis of the screw.

Abstract: A screw feed apparatus for use with a power screwdriving tool comprises a casing relatively slidably mounted on an adapter detachable to the tool, a pair of brackets mounted to the forward end of the casing, a pair of feed sprockets disposed within the brackets and engageable with a magazine belt which carries a series of self-drilling screws, a ratchet wheel supported by the brackets so as to be co-rotatable with the feed sprockets, a slide member supported on the casing so as to move toward the ratchet wheel in response to forward movement of the adapter and move away from the ratchet wheel in response to rearward movement of the adapter, and a claw member operatively supported by the slide member so as to force the ratchet wheel to rotate intermittently by a regular pitch as the slide member moves away from the ratchet wheel.