a helical groove on a shaft
a helical ridge and groove either externally on a cylindrical screw or bolt , or internally on a cylindrical nut that mate with each other by rotation
a ridge in the form of a helix on a cylindrical core
The screw and nut pair can be used to convert torque into linear force. As the screw (or bolt) is rotated, the screw moves along its axis through the fixed nut, or the non-rotating nut moves along the lead-screw. A screw thread is a helical or tapered structure used to convert between rotational and linear movement or force.