The NAS1291 Series

Welcome to the NAS1291.info website, a source of technical information on applications and limitations of this aerospace fastener.

NAS1291 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 stainless or alloy steel. These nuts were first approved as a national aerospace standard in June of 1959. 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.

Some versions of the NAS1291 lock-nut have been superseded by NASM21042 and NASM21043. For more information on these, please visit our sister site, MS21042.info

The NAS1291 series of nuts ranges in size from 02 to 10, with corresponding thread diameters of .086 to .6250 inches. The standard specifies alloy-steel and A286 stainless steel variants.

NAS1291 Sizes