The MS21042 Series
Welcome to the MS21042.info website, a source of technical information on applications and limitations of this aerospace fastener.
MS21042 lock-nuts are widely used throughout the aerospace industry. They are a thin-walled, self-locking nuts with a reduced height and are made of alloy steel. These nuts were first approved as a United States military standard in September of 1959. In 1998, the AIA (Aerospace Industries Association) took over the management of these prints from the military under NASM21042. Since their inception, their use as expanded, driven by the need for affordable, high strength weight saving fasteners. As a result, many engineers, OEMs, mechanics, and even manufactures may be unaware of this fastener's limitations.
The MS21042 series of nuts ranges in size from 02 to 6, with corresponding thread diameters of .086 to .3750 inches.