A drilling screw, particularly a two-component steel screw, having a head part and a cutting part, wherein the head part is made of a corrosion-resistant material and comprises a screw head and a shank section, and wherein the cutting part is made of a hardenable material, a cemented carbide, or a technical ceramic, characterized in that an intermediate section made of a corrosion-resistant material is disposed between the shank section and the cutting part, which intermediate section is non-releasably connected to the shank section, wherein the cutting part comprises a peg-like projection or a cup-like recess and wherein the intermediate section comprises a cup-like recess or a peg-like projection, wherein the cup-like recess or a peg-like projection has an engagement profile with multiple engagement sections in its cross section, wherein said peg-like projection is disposed in the cup-like recess and wherein said intermediate section is permanently connected to the cutting part by means of impact extrusion, such that the peg-like projection of the cutting part axially undercuts at least sections of the intermediate section in the region of the cup-like recess or such that the peg-like projection of the intermediate section axially undercuts at least sections of the cutting part in the region of the cup-like recess.

A screw capable of drilling holes easily and discharging dregs effectively includes a head; and a stem. The head is formed by an upper portion and a lower portion. The upper portion is a round disk. The annular ring of the round disk of the head is formed with a plurality of inclined protrusions. Recesses between the protrusions extend from an inner edge of the round ring to an outer edge of the round ring and are arranged along un-radial paths. A periphery of the lower portion of the head is formed with at least one knife sheet which extends from the annular ring of the round disk of the head to the stem; and the direction of the knife sheet is inclined to an axis of the lower portion of the head. At a connection of the head and stem, the knife sheet has a maximum height and width.

A screw with a flat drilling end comprises a cylinder (1) with a thread (11) wrapped around and a flat drill portion (2) longitudinally extended from a distal end of the cylinder (1); a maximum thickness (T) of a transversal cross section of the flat drill portion (2) being less than a half of the maximum width (D) of the transversal cross section of the flat drill portion (2); the maximum width (D) of the transversal cross section of the flat drill portion (2) being smaller than an outer diameter of the thread (11) of the cylinder (1); the width and thickness of the transversal cross section of the flat dill portion (2) being reduced to a point tip end of the flat drill portion (2). Two opposite lateral sides form as sharp knife blades.

Disclosed is a chip removal structure of a screw. The screw includes a screw head. A shank extends downward from the screw head. The shank has an outer circumferential surface on which a thread is formed in a surrounding form. The shank has a lower end that is formed with a tapering tail section. The thread is extended to the tapering tail section. The tapering tail section is formed, through cutting or pressing, with two or more chip removal grooves. The spacing distance of the chip removal grooves can be adjusted as desired. The chip removal grooves are set at an inclination angle and any one of the chip removal grooves may exceed or may not exceed a screw center line. The chip removal grooves on the left side are each 0.5 to 4.5 times in width of the chip removal grooves on the right side.

A structure of a self-drilling screw is disclosed. The screw includes a screw head and a shank extending downward from the screw head. The shank has an outer circumferential surface, around which a thread is circumferentially formed. The shank has a lower end forming a drilling tip section. The thread is extended or not extended into the drilling tip section. The drilling tip section is formed with at least one first chip removal groove. The first chip removal groove has an upper end and at least one second chip removal groove is arranged to extend from the upper end along the shank in a direction toward the screw head.

A threaded fastener is provided. The threaded fastener includes a shank having a non-threaded portion and a threaded portion. A tip extends from the threaded portion and a head extends from the non-threaded portion. A plurality of wings extend from the shank and are configured to form a passage as the threaded fastener advances. An enlarged portion is configured to seat in the passage formed by the plurality of wings with the threaded fastener in an installed arrangement.

An anchor fastener is described. The anchor fastener includes a head, a generally cylindrical shaft extending from the head, a base at a distal end of the shaft, and at least one frangible portion configured to frangibly connect the shaft to the base. The shaft includes a helical thread that extends along an outer surface of the shaft towards the distal end of the shaft. The frangible portions are separable from the base and the shaft under application of a force to the shaft. The base includes a distal surface and an engagement portion configured to engage an object to be anchored to a mounting surface and configured to hold the anchor fastener to the object before installation of the shaft through the object and into the mounting surface. The base includes a thread guide configured to support the helical thread during installation of the shaft.

A flooring screw comprises a screw head, a screw shank connected with the screw head, and a cone connected with screw shank. The screw shank includes a first shank section connected with the screw head, a second shank section connected with the cone, a first thread formed on the first shank section, a second thread extended from the cone to the second shank section and running helically along a direction opposite the direction of the first thread, and a third shank section between the first shank section and the second shank section. The third shank section includes a plurality of peaks protruding outward radially and a plurality of troughs formed between the peaks and recessed radially with respect to the peaks. The peaks and the troughs form an unsmooth surface on the third shank section.

A screw includes a shank, a first thread, and a second thread. The shank includes a screw-in portion, a head portion, and a straight rod portion between the screw-in portion and the head portion. The first thread surrounds the shank spirally and includes an upper thread portion formed around the straight rod portion, a lower thread portion formed around the screw-in portion, and a middle thread portion continuously connected between the upper and lower thread portions. A plurality of serrate cutting teeth is provided on the middle thread portion of the first thread. The second thread is helically formed around the screw-in portion of the shank and includes a plurality of thread convolutions spaced from thread convolutions of the lower thread portion of the first thread. The screw can be quickly driven into articles to be joined without degradation of binding capacity between the screw and the articles.

A screw has a shaft section which extends axially, a screw thread at the shaft section, which screw thread has thread turns that extend radially starting from the shaft section, a screw tip section which connects to the shaft section, at least one first scraping edge at the screw tip section, and at least one second scraping edge in a region of the shaft section adjacent to the screw tip section. The at least one first scraping edge and the at least one second scraping edge are spaced at a distance from each other and extend in an axial direction over different areas of the screw.