What Are The Most Important Things To Know About Buying Mil-Spec Fasteners?

Fasteners used in military equipment must have the tensile, hardness, material qualities, plating, drive type, and dimensions specified by the US Department of Defense. The DOD sets the standards to ensure that each piece of equipment meets specific interoperability, commonality, and reliability.

Since the military has no margin for error, contractors, engineers, and distributors serving the defense sector must comply or risk losing their contracts. This post sheds some light on the most important things to look for when buying mil-spec fasteners to avoid costly mistakes.

Purchase From a QLSM-Approved Factory

Primarily, mil-spec fasteners are produced by factories certified by the federal government to manufacture and supply the fasteners. Unlike ordinary companies, the QLSM-approved manufacturers fabricate fasteners following the strict standards set by the department of defense.

Fasteners from these factories have the required hardness, plating, dimensions, materials, threads, and tensile strength. Such factories have an obligation to follow the best industry practices, lest they lose their accreditation to produce Mil-STD fasteners.

The QLSM-approved factories produce all fasteners, including screws, nuts, bolts, cable ties, pins, sockets, and washers. That means you get everything from the same factory, saving the time you could have wasted ordering fasteners from different factories.

Material Attributes of Mil-Spec Fasteners

Mil-spec fasteners are designed from materials with excellent resistance to vibrations, physical impact, adverse weather conditions, and shock. The material should be tough enough to meet the stringent demands of the nuclear, defense, government, and marine sectors.

The military prefers 300 series stainless steel, steel cad, cad yellow steel, and 410 stainless steel. Furthermore, the fasteners could be made from other materials like brass, silicon bronze, aluminum, and bronze.

Certificate of Conformity

When purchasing Mil-spec fasteners, ask for the certificate of conformity, proof showing that the fasteners have met all the manufacturing standards set by the department of defense. The certificate specifies the manufacturer to simplify traceability in the event of a manufacturing blemish.

Furthermore, the certificate of conformance gives important details like the chemical composition of the material used in fabrication, the part description, treatment of material, a list of standards that the fastener has passed, manufacturing date, lot number, and the place where the fastener was tested.

DFARS Compliance

The Defense Federal Acquisition Regulation Standard requires manufacturers to source their fastener materials from factories in the United States. The requirement was implemented to reduce overdependence on foreign countries.

Nonetheless, in some cases, manufacturers can outsource fastener materials from qualifying countries like Sweden, Egypt, Netherlands, Canada, Australia, Northern Ireland,  Israel, Greece, Italy, Portugal, Spain, Turkey, Finland, and Denmark.

Besides, QLSM-approved manufacturers can get raw materials from Latvia, Spain, Slovenia, Japan, Switzerland, Poland, and the United Kingdom. Therefore, before buying Mil-fasteners, ask the manufacturer to show proof of DFARS compliance.

Head Marking

Typically, Mil-spec fasteners have the MS, NAS, or AN head marking, which serves as an identifier to help you purchase the right fastener for the right application. For instance, some fasteners bear the military standard (MS) mark, which means contractors can use the fasteners for non-military applications, and DOD contract work.

Other fasteners have the Army Navy (AN) mark, which means they are for repairing or making aircraft used by the US Navy. Fasteners with the National Aerospace Standard (NAS) mark are designed for the general aerospace industry.

Get Your Mil-Spec Fasteners From Big Bolt

From bolts, washers, screws, studs, and nuts, Big Bolt's inventory has over 6 million blanks and finished goods fasteners, letting defense engineers and contractors find the exact one needed for the task at hand. You can hardly miss the right fastener for the construction, agricultural, transportation, maritime, and aerospace sectors.

Suppose you miss the fastener you want, Big Bolt will quickly thread fasteners that meet the specific military and government standards required — no sacrificing quality. Thanks to our state-of-the-art factory with equipment for machining, threading, milling,  plating, and forging.

Don’t let supply chain issues get in the way of finishing your next project on time. Contact us for a quote or more information about our mil-spec fasteners.