Screw

grabcad

A screw, also known as a bolt, is a metal fastener with a helical ridge or male thread wrapped around a cylinder. It can mate with a complementary female thread (internal thread) in the form of a nut or an object with an internal thread. Alternatively, it may cut a helical groove in softer materials as it's inserted. Primarily, screws are used to join objects together and position them accurately.