Screws are also male threaded fasteners mostly related and clearly undistinguished from bolts. While bolts mate with corresponding nuts, screws do not need any mating fasteners. Unlike bolts, screws need not have plain non-threaded shank. Screws may have tapered threads so as to facilitate succession into the female component.
Screws must always be turned to assembly the joint. Unlike bolts, screws are often smaller diameter fasteners which are produced in cold forged condition. Large diameter screws can be produced economically from bar stock or can be hot forged, followed by machining and threading.
Please click for list of thread standards.