Bolt

Nut and bolt

A bolt is a form of grooved fastener with an external helical male thread that engages the interior female thread of a nut. Bolts are closely related to, and often confused with, screws.^[1]

T-shaped bolts are metal screws with a T-shaped cap and a metric thread on the rod. The products are used in the construction of berthing facilities, mechanical engineering and instrumentation, and the production of machine tools.^[2]

A screw is different from a bolt, because it does not take a nut, and its helical thread is used to penetrate (cut into) a softer material (such as wood).

This distinction is not always clear, and sometimes screws are regarded as bolts without a nut.