Self-tapping screws are used for non-metal or soft metal, without drilling low holes and tapping; Self-tapping screws are pointed so as to "self-tap"; Ordinary screws are flat-headed with the same thickness. Self-tapping screws mean that the holes drilled are holes without tapping. The screws used are different from those used in general. The head is sharp and the pitch is relatively large, which is a bit like the chipless tapping, and can be directly screwed in without tapping. Metals and plastics usually use this method. It can "tap-drill, squeeze and press" the corresponding threads on the consolidated material by its own threads, so as to make them fit closely with each other. Entry label: