Abstract: An anti-split wood screw includes a screw head and a shank. The shank has a tip portion connected to a distal end thereof, a first thread extended helically from the front end of the tip portion toward the distal end of the shank, a second thread extended helically from the distal end of the first thread toward the shank, and a third thread extended helically from the distal end of the second thread toward the middle of the shank. The second thread has a plurality of serrated cutting edges and teeth peaks that are alternately disposed. The anti-split wood screw thus formed can tap an object through the first thread, cut off the chips generated during tapping through the second thread, and channel out the chips through the third thread without being clogged by the chips, hence can avoid the object from splitting and damaging.

Abstract: An anti-split wood screw includes a screw head and a shank. The shank has a tip portion connected to a distal end thereof, a first thread extended helically from the front end of the tip portion toward the distal end of the shank, a second thread extended helically from the distal end of the first thread toward the shank, and a third thread extended helically from the distal end of the second thread toward the middle of the shank. The second thread has a plurality of serrated cutting edges and teeth peaks that are alternately disposed. The anti-split wood screw thus formed can tap an object through the first thread, cut off the chips generated during tapping through the second thread, and channel out the chips through the third thread without being clogged by the chips, hence can avoid the object from splitting and damaging.

Abstract: A concrete screw includes a screw head and a rod with a drilling tail section at a distal end thereof. The rod includes a first thread section formed annularly thereon and extended upwards from the drilling tail section, and a second thread section encircling between at least two thread pitches of the first thread section and having an outer diameter smaller than that of the first thread section. The rod further includes a third thread section on an upper end thereof encircling between at least two thread pitches of the first thread section. As the outer edge of the second thread section butts the wall of the screw hole, the first thread section can steadily perform cutting without swaying. Moreover, through the third thread section, compact effect is thereby achieved at a position near the screw head. Hence the concrete screw can provide precise, effort-saving and steady fastening effect.

Abstract: A screw comprises a head and a rod extended downward from the head. The rod has a tip at a distal end and a round thread spirally extended upward from the tip. The round thread is an asymmetric thread and has serrated cutting edges extended upward from the tip and formed along a circumference in a desired distance. The rod also has a cutting thread with a plurality of spiral cutting edges spirally extended upward from the tip in the same spiral direction as that of the round thread. When the screw is screwed into a workpiece, the asymmetric thread can effectively reduce resistance of screwing. Further, the serrated cutting edges and the cutting thread of the invention can increase the cutting effect. Thereby, the screw of the invention enables the user to fasten workpieces faster with less effort.

Abstract: A screw has a screw head and a shank. The screw head has a square cavity, a hexagonal cavity or a hexagonal boss to be wedged by a screw driver for wrenching. The shank has a first asymmetrical thread at the taper to facilitate drilling holes, asymmetrical saw-type threads behind the first asymmetrical thread, and a second asymmetrical thread behind the asymmetrical saw-type threads. The shank further has a carved V-shaped tail between the first asymmetrical thread and the asymmetrical saw-type threads to facilitate cutting and debris dispelling. The screw thus formed can rapidly perform thread tapping and debris dispelling, and reduce friction and expand drilling holes and achieve fast fastening.

Abstract: A screw has a screw head and a shank. The screw head has a square cavity, a hexagonal cavity or a hexagonal boss to be wedged by a screw driver for wrenching. The shank has four sections of threads on the periphery. A first thread is asymmetrical to facilitate drilling holes and spaced with a first threaded pitch. A second thread has a carved V-shaped tail end extended in a direction of the shank at a length larger than one of the first threaded. A third thread has asymmetrical saw-type threads, and a fourth tread is asymmetrical. The screw thus formed can rapidly perform thread tapping and debris dispelling, and reduce friction and expand drilling holes and achieve fast fastening.

Abstract: A capped screw includes a head disposed on top, a gasket engaged onto the screw and engaged with the bottom surface of the head, and a cap having a chamber for receiving the head of the screw and having a downwardly extended peripheral skirt which has a lower portion folded radially and inwardly to engage with the gasket and to secure the gasket to the head of the screw. The screw includes a peripheral flange extended radially outward from the head, the cap includes a radially extended peripheral flap, the peripheral skirt is extended downwardly from the peripheral flap.