Bolts are threaded rods or pins that fasten objects together. They usually have a head at one end and a thread at the other. Bolts are secured by threaded nuts, and are available in both metric and non-metric designations.
Screws are fasteners that consist of a threaded shaft at one end and, typically, a head at the other. They are inserted into solid materials and secured via rotation.
Washers are disks of metal or non-metallic material placed beneath a nut, an axle bearing, or a joint, to relieve friction, prevent leakage, isolate, prevent loosening, or distribute pressure.
