A high-strength screw (1) includes a head (2) having a tool engagement external contour (7) and a tool engagement internal contour (8). For example, the tool engagement external contour (7) is an external hexagonal and the tool engagement internal contour (8) is an internal hexagonal. A plurality of additional pocket-shaped impressions (13) are arranged in the tool engagement internal contour (8) between corners (12).

A screw includes a head having a top surface where a drive socket and drive regions are recessedly formed. Each drive region has two non-parallel side walls and two different drive walls. One drive wall is connected to the side walls to form a groove communicating with the drive socket. The other drive wall is connected between two adjacent side walls of two adjacent grooves. At least one of the drive walls slopes downwards from the top surface at a slope of at least 1 degree. Each side wall connecting between the drive walls deviates inwards by an angle difference of at least 1 degree. The slope and the inward deviation of the walls receive a driving tool firmly to prevent a swinging problem and enhance the torque transmission. A punch adapted to form the recessed screw also facilitates a long-term production without losing the accuracy thereof.

A drive system with full surface drive contact. The drive system tends to maximize the surface contact pattern or area at typical bit-recess reaction (drive) torque values, thereby tending to minimize bit-recess surface contact stresses, coating damage, recess ream and premature bit fatigue failure. The drive system comprises a fastener and/or bit having drive surfaces formed of either polygon involutes or a single arc construction. A punch is also provided for forming a recess in either the fastener or the bit, wherein the punch has corresponding surfaces.

Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow stick fit engagement of existing standard straight walled drivers in the new system.

A recessed fastener includes a head with a top face and a drive socket, a shank extending downward from the head, and threads helically around the shank. The drive socket has a bottom and drive walls extending upward therefrom. The bottom meets the drive walls at a bottom border. The drive walls meet the top face at a top border. The bottom border and the top border have respective first and second corners. The first corners are rotatably offset relative to the second corners. A joining line is connected between each first corner and each second corner, and one drive wall formed between two adjacent joining lines is in a spiral form. The spiral drive walls leads a driving tool toward the bottom to produce an automatic downward pressing force which facilitates the close engagement, thereby obtaining a quick driving operation, an increased driving power and a labor-saving effect.

A screw plug for a liquid conduit, particularly an oil pipe or an oil container, comprising a cylindrical shaft that is placed on a top plate and is provided with an external thread. A pocket hole having a polygonal cross section is centrally arranged on the top plate as a receiving member for a tool. The shaft is embodied as a tubular butt that is provided with the external thread. A pocket hole which is arranged coaxial to the pocket hole of the top plate extends from the face of the shaft. In order to produce the screw plug, a blank comprising the cylindrical tubular butt that is connected to the top plate in a molded on manner is made, the inner diameter and outer diameter of the tubular butt being smaller than the final corresponding diameters (e, f) of the screw plug. The tubular butt of the blank is then enlarged by applying pressure to the inner wall surface of the pocket hole thereof. Also disclosed is a tool in which one end of a pressure die is fixed as a mandrel-type tool while a supporting or holding head which is disposed so as to be movable relative thereto and encompass a seat for a blank is associated with the free end thereof.

Punch pins which have further extending lobes, and which are designed to punch sockets that have deeper flutes while not having lobes which extend further toward a center axis of the fastener. Using such a punch pin to form a socket in a fastener provides that the resulting socket has flutes which are deeper than they otherwise would be, without having to provide corresponding lobes which extend further toward the center axis of the socket. This extra deepness in the flutes helps to provide extra room for a coating to deposit.

Fasteners, drivers, punches, fastener systems, and methods of making fasteners, drivers, punches, and fastener systems are disclosed herein. The fasteners, drivers, punches, and fastener systems include, in one example, stabilizing ribs and corresponding recesses.

Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow stick fit engagement of existing standard straight walled drivers in the new system.

Fasteners, drivers, punches, fastener systems, and methods of making fasteners, drivers, punches, and fastener systems are disclosed herein. The fasteners, drivers, punches, and fastener systems include, in one example, stabilizing ribs and corresponding recesses.