Screw

A screw is a fastener with a spiral ridge, the thread, wound around a shaft. Turning it pulls two parts tightly together, and it can be undone for repairs. A TV has dozens, fixing the boards, panel, chassis, covers and stand.

Most are made from low-carbon steel wire by cold forming, without cutting metal away. A machine snips the wire into short pieces and strikes one end in dies to form the head and its slot or cross recess, often hundreds a minute. The blank then rolls between two grooved dies that press the thread into the shaft. Rolling squeezes rather than cuts the steel, which makes the thread stronger. Some screws are then hardened by heat treatment. Finally they are electroplated with a thin layer of zinc, often topped with a coating that gives a silver or yellowish sheen. Zinc corrodes more readily than steel, so it sacrifices itself and protects the screw from rust.

In the television, two main types are used: machine screws, which go into threaded holes in metal, and self-tapping screws, which cut their own thread in plastic. The wall-mount holes follow the VESA standard and take metric screws, usually M4, M6 or M8.