A screw includes a head having a top face and a conical bottom surface, a shank, and thread convolutions. A chip guiding channel is recessedly formed on the conical bottom surface. On the conical bottom surface are spirally disposed a cutting portion which has a plurality cutting units sequentially arranged in a spiral manner, thereby allowing the chip guiding channel to be surrounded by the cutting units along a spiral track. The spiral arrangement of the cutting units assists the head in cutting fibers of a workpiece which are wound around the head into small chips in a continuous and spiral severing manner to reduce drilling torque and resistance, and the spirally-defined chip guiding channel also facilitates a smooth removal of the chips, thereby allowing the head to fit level with a top surface of the workpiece and increasing a fastening effect.

A self-tapping screw for use in securing at least two materials together. The self-tapping screw may include a screw cap that receives a screw body to reinforce the strength of the screw head. The screw cap is composed of a zinc-aluminum alloy that may be die casted and provides additional strength and hardness to the attached screw body. The screw cap has a rolled flange that helps to securely retain the flat rim of the attached screw body.

A bushing includes an upper collar with a lower sheath and an annular shoulder intermediate the collar and sheath. The collar has a plurality of spaced apart notches and the sheath has a plurality of spaced apart slits that may be circumferentially aligned with the notches. The sheath has a plurality of spaced apart ribs projecting outward circumferentially offset from the slit for assisting in maintaining the sheath within a hole in a fastener with the annular shoulder against the fastener. A securing member with an elongate shank extending from a head with a distal portion is maintained in the longitudinal opening in an upright position aligned with the hole. As the fastener is driven longitudinally through the opening and hole, force from the fastener causes the bushing to break away and yields direct contact between the securing member head against the top surface of the fastener.

A wood screw includes a head end, a shank and a tapered end, the head end including a tool engaging part, the head end located at a first end of the shank and the tapered end located at a second end of the shank. A thread is formed along the shank. The head end includes a neck running from the first end of the shank to a head cap, wherein the head cap includes an underside facing the tapered end, wherein the underside includes a plurality of serrations extending around the underside, each serration having a leading face and a trailing face that define a cutting edge, wherein the trailing face of each serration tapers away from the tapered end. A reaming section may be provided between the thread and the head end. The thread may include a notch configuration. The thread may be a dual start thread.

A tolerance compensation element that compensates for tolerances in the distance between first and second components, includes a thread bolt having a first drive feature, a first thread of a first thread direction and a second thread of a second thread direction. Between the first and the second thread, a protrusion extends from the thread bolt radially to the outside. The element includes a first plastic overmold in the portion of the first thread, which provides a fastening structure for the fastening to the first component, and a second plastic overmold around the protrusion which extends radially to the outside, to provide an abutment portion abutting the second component when in use. A distance of the second plastic overmold to the first plastic overmold is changeable after overcoming a start-up torque between the first plastic overmold and the first thread in longitudinal direction of the thread bolt.

A fastener includes a screw structure having threads and a dowel structure. The dowel structure includes a shank extending from the screw structure in an axial direction and connected to the screw structure, and a head engaged to the shank portion and disposed distally from the screw structure. A length of the dowel structure is greater than or equal to a length of the screw structure.

A novel plastic anchor design allows for the use of a wide range of thread-cutting screw lengths without exceeding the recommended engagement length. In accordance with the principles disclosed herein, an anchor comprises an engagement area and a relief chamber. The anchor is configured to be secured into a surrounding material. The engagement area is configured to engage with a screw to secure the screw when fastening an object in place. The relief chamber receives any excess length of the screw that extends beyond the engagement area. This allows the length of engagement between the screw and the anchor to be controlled for various lengths of screws or thicknesses of objects to be fastened.

A cement board screw a high thread that begins on the tapered end, extends onto the shank and terminates at a second axial location along the shank. The high thread defines a high peripheral edge, where a leading flank and a trailing flank meet at the high peripheral edge and together define a high thread angle that is between about thirty degrees and about fifty-five degrees. A low thread begins on the tapered end, extends onto the shank and terminates substantially at a first axial location along the shank such that an axial length of the low thread is less than an axial length of the high thread. The low thread includes a leading flank and a trailing flank that meet at a low peripheral edge and together define a low thread angle that is between about fifty degrees and about seventy degrees.

A self-drilling screw includes a leading section having a drill body and opposite discharge grooves formed on the drill body. The drill body and the discharge grooves meet at cutting edges. On the drill body are formed two blade portions connected to the cutting edges and tapering at respective second tips. The blade portion has a second included angle of not more than 50 degrees. Between the blade portions is formed a drilling portion terminating at a first tip and having a first included angle of not more than 60 degrees. Two opposite concave surfaces each extend from the drilling portion to each blade portion. The first tip and the second tips are situated at different places. Accordingly, the end of the leading section presents a shape of a curved bow riser to cut quickly and help quick removal of chips, thereby decreasing resistance and preventing the cracking problem.

A fastener unit and related method for securing a board to a support is provided. The fastener unit includes a spacer block, a grip element extending from the spacer block and configured to fit in and engage a groove of the board, and one or more board engagement elements extending from a portion of the spacer block. The board engagement elements can clamp the board, between an upper and/or lower surface of the board and a groove of the board, thereby securing the spacer block in a position adjacent the groove to establish a gap between the board and another board. Related methods of use also are provided.