Aerospace & Mil-Spec Fasteners

Aerospace and defense subcontractors buying mil-spec hardware need two things at once: the right part to the right revision, and paperwork that will actually clear incoming quality inspection. Eugene Fastener has been supplying industrial and aerospace fastener hardware since 1969. We source MS, NAS, and AN fasteners through authorized master distributors, manage certified secondary processing such as black oxide and self-locking element application, and hold every lot together from mill to delivery so the certification package matches the parts in the box. This page covers what we handle, how the paperwork works, and how to get a quote.

What We Do

Eugene Fastener runs a build-to-suit model for aerospace and mil-spec hardware. We don’t keep a speculative aerospace shelf stock — we don’t need to. Instead, we work from your spec and quantity, source the hardware through authorized master distributors who carry manufacturer traceability back to the mill, route any secondary processing your spec calls for, and assemble one certification package that covers the hardware and every process applied to it.

That model exists because mil-spec buying isn’t really about the fastener. A 1/4-28 bolt is a 1/4-28 bolt. What makes it an MS or NAS part is the chain of documentation behind it — the mill cert, the manufacturer’s certificate of conformance, the plating or coating cert if the spec calls for a finish, and a lot number that ties all of it together. We manage that chain so your quality department gets a package that reconciles, not one they have to chase down after the parts already shipped.

• Sourcing: MS, NAS, and AN hardware through authorized master distributors with mill-to-delivery traceability.
• Processing: certified secondary operations — black oxide, plating, and self-locking element application — routed to qualified processors per the governing spec.
• Documentation: one certification package covering the hardware and every process applied to it, not a folder of mismatched paperwork from different vendors.
• Quoting: submit spec, quantity, and requirements; we turn around a quote within one business day.

We provide full manufacturer certification packages, certificates of conformance, and lot traceability with every order. Mil-spec and aerospace hardware ships to U.S. domestic addresses only.

Here’s what that build-to-suit flow looks like from RFQ to your dock:

Part Families We Handle: MS, NAS, and AN

These three prefixes cover most of the hardware called out on aerospace and defense drawings. They come from different standards bodies but show up side by side on the same bill of material, and buyers new to mil-spec purchasing often aren’t sure which one they’re actually looking for. Short version: AN is the oldest series (Air Force-Navy, dating to World War II-era standardization), MS covers Military Standard hardware maintained under the Defense Logistics Agency system, and NAS covers National Aerospace Standard hardware maintained by the Aerospace Industries Association — generally tighter tolerance, higher-strength parts for structural and flight-critical applications.

MS (Military Standard) Hardware

MS parts are the broadest family and cover everything from washers and lock washers to nuts, bolts, pins, and self-locking hardware. Examples we handle regularly:

• MS35338 — split lock washer, inch series
• MS21042 — self-locking reduced-hex nut
• MS-series bolts, screws, and pins across standard aerospace materials (corrosion-resistant steel, alloy steel, titanium)

NAS (National Aerospace Standard) Hardware

NAS parts are typically the higher-strength, tighter-tolerance option for structural and flight-critical joints — close-tolerance bolts, high-strength fasteners, and precision hardware where the drawing calls out NAS specifically rather than an MS equivalent. Example we handle regularly:

• NAS1149 — flat washer, aerospace grade

AN (Air Force-Navy) Hardware

AN parts are the legacy airframe series, still widely called out on older drawings and still in active production for sustainment and repair work. Examples we handle regularly:

• AN960 — flat washer, airframe series
• AN3 — the start of the AN3 through AN20 airframe bolt series (AN3 is nominally 10-32 thread, 3/16" diameter)

For help decoding a part number you’re not sure about, see our companion guide, MS, NAS & AN Fastener Numbering Guide, which breaks down how each numbering system encodes material, diameter, and length.

Secondary Processing Services

A lot of mil-spec hardware doesn’t ship in its raw manufactured state — the drawing or spec calls for a finish, a coating, or a self-locking feature added after the part is made. We manage this processing through qualified processors and fold the resulting certs into your final documentation package, so you’re not left tracking down a plater’s paperwork separately from the fastener manufacturer’s.

Black Oxide (MIL-DTL-13924)

Black oxide conversion coating per MIL-DTL-13924 is one of the most common finish calls on steel aerospace hardware — it’s thin, doesn’t add dimensional buildup the way plating can, and gives modest corrosion protection along with a non-reflective finish. We route black oxide processing to qualified processors and include the process certification in your final package.

Self-Locking Thread Element (MIL-DTL-18240)

When a drawing calls for a self-locking nut or bolt with a patch or insert rather than a separate lock washer, that locking feature is typically qualified to MIL-DTL-18240. We can source hardware with the locking element already applied by the manufacturer, or route application to a qualified processor when the base hardware and the locking feature come from different sources. Either way, the locking element certification travels with the rest of the package. For background on how these fasteners work and where they’re specified, see our companion guide, Self-Locking Fasteners Guide.

Plating (including Cadmium per QQ-P-416)

Cadmium plating per QQ-P-416 remains a common call-out on legacy aerospace drawings for corrosion protection and galvanic compatibility with aluminum airframes, and we route it along with other plating finishes through qualified processors. If your drawing specifies a particular plating class or thickness, tell us on the RFQ and we’ll confirm the processor can meet it before quoting.

For a broader rundown of finish options and how to read the finish call-out on a drawing, see our companion guide, Mil-Spec Coatings & Finishes Guide.

Paperwork and Lot Traceability

The paperwork is often the harder part of a mil-spec order to get right, and it’s where orders most often get held up at receiving inspection. We provide full manufacturer certification packages, certificates of conformance, and lot traceability with every order — assembled so the lot numbers on the paperwork match the lot numbers on the parts, and so processing certs (plating, black oxide, locking element) tie back to the same lot as the base hardware cert.

We keep the chain unbroken from the mill through any secondary processing to delivery. That means if your quality department needs to trace a part back to melt source or verify which processing lot a batch of black oxide parts came from, the documentation supports it without gaps.

If you’re new to reading a mil-spec cert package or want to know what should be in the folder before you sign off on receiving, our companion guide walks through it in plain language: What’s in a Mil-Spec Fastener Certification Package. If your contract carries specialty metals or domestic sourcing requirements, also see our DFARS-Compliant Fasteners Guide.

How to Request a Quote

Because we build to your spec rather than quoting off a shelf, the fastest way to get an accurate quote is to give us the full picture up front. Include:

1. The part number or governing spec (MS, NAS, or AN number, or the drawing call-out if it references a spec directly).
2. Quantity, and whether it’s a one-time buy or a recurring requirement.
3. Material and finish called out on the drawing, including any secondary processing (black oxide, plating, self-locking element).
4. Certification requirements — certificate of conformance, material test report, DFARS flow-down language if your contract requires it.
5. Traceability requirements — full lot traceability is standard with every order, but tell us if your contract has additional documentation requirements beyond that.
6. Ship-to address — note that mil-spec and aerospace hardware ships to U.S. domestic addresses only.

Submit that information through our RFQ form or by phone, and we’ll quote within one business day.

Frequently Asked Questions

What’s the difference between MS, NAS, and AN fasteners?

They’re three different standards families that show up on the same aerospace bill of material. AN (Air Force-Navy) is the oldest, dating to WWII-era standardization. MS (Military Standard) is maintained under the Defense Logistics Agency system and covers the broadest range of general hardware. NAS (National Aerospace Standard) is maintained by the Aerospace Industries Association and generally covers higher-strength, tighter-tolerance parts for structural and flight-critical joints. Your drawing will call out the specific prefix and number you need.

Do you stock aerospace fasteners, or do you source them per order?

We work on a build-to-suit model. Rather than carrying speculative shelf stock across every MS, NAS, and AN part number, we source through authorized master distributors once we have your spec and quantity. This keeps lead times predictable and means every part we deliver comes with full manufacturer traceability, rather than pulling from unverified stock.

Can you handle secondary processing like plating or self-locking elements?

Yes. We route black oxide (MIL-DTL-13924), plating including cadmium per QQ-P-416, and self-locking thread element application (MIL-DTL-18240) through qualified processors, and fold the resulting process certifications into your final certification package.

What certifications come with an order?

Every order includes full manufacturer certification packages, certificates of conformance, and lot traceability. If your contract requires DFARS flow-down language or other specific documentation, tell us on the RFQ and we’ll confirm it’s included before quoting.

Do you ship internationally?

No. Mil-spec and aerospace hardware from Eugene Fastener ships to U.S. domestic addresses only.

How fast can I get a quote?

Submit your spec, quantity, and certification requirements through our RFQ form or by phone, and we’ll turn around a quote within one business day.

Related Resources

• What’s in a Mil-Spec Fastener Certification Package — C of C, mill certs, plating certs, DFARS flow-down, and a buyer’s checklist
• DFARS-Compliant Fasteners Guide — specialty metals clause, domestic melt, qualifying countries
• MS, NAS & AN Fastener Numbering Guide — how to decode a mil-spec part number (coming soon)
• Mil-Spec Coatings & Finishes Guide — black oxide, plating, and other finish call-outs (coming soon)
• Self-Locking Fasteners Guide — patch, insert, and reduced-hex locking nut designs (coming soon)