Feature:Self-drilling screw, in addition to the tap-like flute in the leading threads, there is also a drill-like fluted tip that looks much like the tip of a center drill. These screws combine a threading-like action and the fastener installation itself into only one driving motion (instead of separate drilling, tapping, and installing motions); they are thus very efficient in a variety of hard-substrate applications, from assembly lines to roofing.Hex washer self drilling screws can be can be locked more firmly if the screws vibration occurs，the flange part can be used as a flat washer, which can be locked firmly on softer and non-wearable materials.According to the thickness of the material,you can choose the self-drilling screws. The thicker the material, the larger and longer self-drilling screws.
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