Abstract: A thread-rolling machine includes a vertical rotating shaft journalled on a machine base, and a thread-rolling unit. The thread-rolling unit includes a plurality of angularly equidistant rotatable rolling plates fixed on the rotating shaft, and a plurality of angularly equidistant fixed rolling plates fixed on the machine base and disposed around the rotatable rolling plates. During rotation of the rotating shaft, nail-shaped blanks are fed simultaneously onto the thread-rolling unit. Each of the blanks is rolled between a respective one of the rotatable rolling plates and a respective one of the fixed rolling plates, thereby forming a bolt.

Abstract: A screw driving gun includes a tubular barrel extending frontwardly from a gun housing to define a chamber in a longitudinal direction, and a tubular slider coupled slidably to a front end of the barrel. A front portion of the tubular slider has two opposing slots in the longitudinal direction for passage of a screw feed belt therethrough in order to register a screw on the feed belt with the chamber of the barrel. A screw orientation guide member is connected to the slider, and has a front section formed with an abutting end for abutting against a work piece surface, and a plurality of holding units cooperatively confining a guide passage in the longitudinal direction between the slider and the abutting end. The guide passage tapers to form a constricted front end proximate to the abutting end. The holding units cooperatively provide radial inward holding forces on the screw to prevent the latter from deviating from the longitudinal direction.

Abstract: A screw feed belt is used to hold a plurality of screws and includes an elongated strap, a plurality of positioning rings, and a plurality of connecting ribs. The strap is made of a flexible material and is formed with a plurality of spaced-apart and aligned openings, each of which is defined by an annular confining wall. The positioning rings are disposed respectively in the openings. Each of the positioning rings has an inner periphery that defines a positioning hole adapted to permit extension of the shank portion of one of the screws and that is adapted to be in frictional contact with the shank portion, and an outer periphery surrounded by and spaced-apart from the confining wall of the respective opening. The positioning hole has a size smaller than the head portion of the screws so that the positioning ring is adapted to permit the head portion to rest thereon when the screw extends through the positioning hole.

Abstract: The shank portion of a screw, which is free of a drill bit portion and which is adapted for use with a fibrous board, has a surface that is formed with a screw thread throughout the length of the shank portion, and a lower section that is formed with a flute at the surface thereof. The flute extends from a tip of the shank portion and has a longitudinal length which is inclined with respect to a longitudinal axis of the shank portion.