Let's take a look at what types of threads are there for self-tapping screws? For example, pan-head self-tapping screws are often represented by letters such as PA, PB, and PT, so what do they mean?

PA stands for taper-tail self-tapping screws, PB for flat-tail self-tapping screws, and PT for cut-tail self-tapping screws. The three pictures are below, why are there so many styles, and what are their uses? Taper-tail self-tapping screws are mainly used to hit wood or plastic parts, while flat-tail self-tapping screws are mainly used on plates with holes drilled first. There is no difference between the two types of threads. The PT tooth self-tapping screw has a slightly different thread arc and shape from the former two. This thread can be disassembled frequently, and the damage to the workpiece will be relatively small.

There is also a triangular self-tapping screw. The triangular self-tapping screw looks a bit similar to the machine screw, but its thread has a slight arc and is triangular.

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