Abstract: A wood screw includes a head part, a tapered insert part, and a shank part disposed between the head part and the tapered insert part. The shank part has first and second shank segments adjacent to the head part and the tapered insert part, respectively. The first shank segment has a first radius. The second shank segment has a surface that is formed with a screw thread. The screw thread includes interconnected thread sections that have a second radius larger than the first radius. The surface of the second shank segment is further formed with at least one projecting element between two neighboring interconnected ones of the thread sections that are proximate to the tapered insert part. The projecting element has a greatest radial dimension with respect to the shank axis that is greater than the first radius and less than the second radius.

Abstract: A screw includes a shank having a head end part, a tapered insert end part, and a surface that is formed with a screw thread that spirals downwardly along an axis of the shank. The insert end part has a surface formed with a flute. The flute has an upper end portion that extends to interrupt a portion of the screw thread, and is defined by two confining side walls which extend radially from the axis of the shank and which form an angle ranging from 90° to 180° therebetween. The upper and lower end portions of the flute have a depth that gradually increases toward an intermediate portion of the flute.

Abstract: A screw feed belt assembly includes multiple screws, multiple washers and a belt body. Each of the screws has a head portion on one end of a shank portion. Each of the washers is sleeved on the shank portion of a respective one of the screws and has a diameter not greater than that of the head portion. The belt body includes an elongated back strap, and at least one strip attached to the back strap and cooperating with the back strap so as to confine multiple spaced-apart positioning holes. The shank portion of each of the screws is inserted into a corresponding one of the positioning holes such that the screws are retained on the belt body and such that each of the washers is disposed between the head portion of the respective one of the screws and the strip of the belt body.

Abstract: A screw drive recess mold for forming screw drive recesses which has a body and a mold base. The mold base consists of four symmetrical fan-shaped protrusions and a center square protrusion. Four elongate rectangular hollow spaces are located in each of the middles between every two neighboring fan-shaped protrusions. A compound screw drive recess formed by this drive recess mold can be driven by various conventional drivers such as of a slot, of a Phillips (cross), of a square, of a cross-square, and of a Pozi. With the tailor made screw driver of this compound drive recess, the drive recess will be able not only to withstand high driving torques but also to securely retain the drive bit (the screw driver) within the recess.

Abstract: Screws with compound threads. Each of the screws includes a head with a compound drive recess therein. The compound drive recess for the screw driver(or the screw drive bit) is shaped to have four symmetrical fan-shaped portions, a center square portion with four faces, and eight chamfer edges intermediate to the center square portion and each of the four fan-shaped portions. The compound drive recess allows the screw to be driven by various screw driver such as slot, Phillips, square, Pozi and cross-square. The compound drive recess can be driven by its tailor-made driver, which gives the compound drive recess the capacity to withstand high driving torques with minimal drive bit slip or cam-out.