|2002-05-09, Rev. 2002-06-03. © 2002 Garrett D. Euler| The
correct definition of bolt and screw is as follows. |Bolts are
defined as headed fasteners having external threads that meet an
exacting, uniform bolt thread specification (such as M, MJ, UN,
UNR, and UNJ) such that they can accept a nontapered nut. Screws
are defined as headed, externally-threaded fasteners that do not
meet the above definition of bolts.| Because various
organizations have thoroughly confused everyone regarding this
simple definition, the remainder of this article dispels several
myths and discusses the full rationale explaining the above,
correct definition. (1) Several dictionaries, Machinery's
Handbook, part specification sheets, military specifications,
bolt manufacturers, and vendor catalogs are wrong and have
botched the above, unambiguous definition. Their definitions of
bolt versus screw are arbitrary, random, ambiguous,
nondefinitive, and do not align with common sense. Having
"credible" sources such as Machinery's Handbook,