From beginning to end is the self tapping screw head, Rod and rod end is composed of three parts. Each composition of the tapping screws has four elements: the head shape, pulling or twisting, thread types, terminal type.
Shape-head shape of the head varied. Round head (head), flat round head, round head flange (with collar), flat round head flange (MAT), Pan, Pan head flange (with collar), countersunk head, countersunk head, cylinder, sphere, cylinder heads, Horn head, Hexagon, Hexagon, hexagonal flange head flange (with collar), and so on.
Plate screw-wrench screw in variety. Outside pull twist: six angle, and six angle flange surface, and six angle convex margin, and six angle spent shaped,; within pull twist: a word slot, and cross slot h type, and cross slot z type, and cross slot f type, and Quartet slot, and composite slot, and within spent key, and within six angle spent shaped (plum slot), and within triangle, and within six angle, and within 12 angle, and clutch device slot, and six leaves type slot, and high torque cross slot and so on.
Thread type-threaded variety. Tapping screw (w thread) drywall screw, machine screw, screw, chipboard screws, as well as some other special thread. Threads can be divided into Dan Daocheng (single head), double lead (dual-head), lead (Bulls) and high and low double thread.
Terminal-Terminal-main saw blade end, flat end. But according to the functions can be processed by a cutting function of Groove, Groove, cuts or similar shape of the bit parts, and so on. In some standards, is also a saw blade or flat end, and there are different forms.
Can be seen from this: tapping screw head shape, pull screw thread type and end type, and so on, there are all kinds of changes. Can be combined between them, and release many different products belong to the category of self tapping screws.
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