Top 27 Mil-Spec Fastener Questions & Expert Answers on AN, MS, NAS & MIL-STD Hardware Frequently Asked Questions About Military Standard (MIL-STD) Hardware (Part 3 of 4) 

Posted: March 30, 2026 | Author: mfsupplyblog | Filed under: DFARS, Domestic Fasteners, Mil-Spec Fasteners | Tags: DFARS Compliant, Domestic Fasteners, Mil-spec, Mil-spec fasteners, Mil-Spec Fasteners Cross-Reference, Mil-Spec Fasteners Distributor, Mil-Spec Fasteners Supplier, Mil-STD, Sourcing Mil-Spec Fasteners |Leave a comment

Welcome back to our 4-part series on Mil-Spec Fastener Questions and Expert Answers.  In part two, we covered Mil-spec fasteners compliance, certifications, and documentation. We also covered what DFARS compliance means, which materials fall under specialty metals rules, what paperwork may be required beyond a standard Certificate of Conformance, how to interpret Mil-Spec part numbers, and where to obtain official prints and supporting documentation. 

In this third installment, we shift from compliance paperwork to sourcing and selection strategy. We’ll cover where to find Mil-Spec fastener lists, catalogs, and specifications; what types of MIL-STD hardware are commonly available, from screws, washers, nuts, and pins to inserts, retaining rings, and more; and which base materials frequently appear in Mil-Spec supply chains. We’ll also address one of the most practical sourcing questions buyers face: when a commercial or OEM functional equivalent may be considered, what tradeoffs can come with that decision, and how to cross-reference a Mil-Spec part number to possible equivalents while keeping form, fit, function, traceability, and documentation requirements in view.

Part 3 – Where to Find Mil-Spec Fasteners, What’s Available, and How to Cross-Reference Equivalents  

15. Where can I find a list of Mil-spec fasteners and specs? 

The Defense Logistics Agency (DLA) is a great resource. They maintain a comprehensive database of specifications and drawings. They also maintain a catalog of hardware that includes National Item Identification Numbers (NIIN) and National Stock Numbers (NSN) that are sometimes called out in a bill of materials. Check out the following links for more comprehensive information regarding hardware: 

• View catalogs of Mil-Spec parts and specs by category 
• Look up / Search a specific Mil-Spec part 
• Check out MF Supply’s Mil-Spec fasteners in stock 
• Download MF Supply’s Mil-spec line card
• Check out the AIA for NAS parts 

16. What types of Mil-Spec fasteners are available?

Thousands and thousands of mil-spec fasteners exist.  At MF Supply, we supply a full range of Mil-Spec/MIL-STD fasteners, including: 

• Chisel Point Cotter Pins : MS9245. 
• Dowel Pins : M21143, MS16555, and MS16556. 
• Hex Head Cap Screws : MS35307, MS35308, MS90725, and MS90726. 
• Helical Inserts : MA3279, MA3329, MS121, MS122, MS124, and MS21209. 
• Keensert-Style Threaded Inserts :MS51830, MS51830A, MS51830CA, MS51831, MS51831A, MS51831CA, MS51832, MS51832A, MS51832CA, NA0146, NA0147, NA0148, NA0149, NA0150, NA0151, NAS1394, and NAS1395.
• Nuts : MS17830, MS35649, MS35650, MS51967, MS51967B, MS51967C, MS51971, MS51972, NAS17830, NAS662C, NAS671, and NAS671C. 
• Machine Screws : AN500AD, AN501AD, AN526C, MS24693, MS24693C, MS35190, MS35191, MS35206, MS35207, MS35265, MS35266, MS35275, MS35276, MS51957, MS51958, MS51959, MS51960, NAS1635, NAS1801, and NAS662C. 
• Retaining Rings : MS16624 and MS16625. 
• Self-Tapping Screws & Drive Screws : MS51861, MS51861C and MS21318. 
• Shoulder Screws : MS51575 and MS51576. 
• Socket Head Cap Screws/Bolts : MS16995, MS16996, MS16997, MS16998, MS51576, NAS1351C, NAS1352C, NAS1351N, NAS1352N, and MS24671.
• Socket Set Screws : AN565, NAS1081, MS180, MS213, MS510, MS514, and MS519. 
• Slotted Spring Pins : MS16562. 
• Standoffs and Spacers: NAS42, NAS43, NAS61, NAS1056, NAS1057, NAS1829, NAS1831, NAS1831, NAS61.
• Washers : AN960, AN960-C, AN960-CL, AN960-L, AN970, MS15795, MS27183, NAS1149, NAS620, MS35333, MS35335, MS35338, and MS51848. 
• Can’t find the product you’re looking for? Contact us for more!

17. What materials are Mil-Spec fasteners made from?

Mil-Spec fasteners are available in a wide variety of materials and platings. Common materials include: 

• Carbon Steel 
• Stainless steel (302, 304, 316, 400 Series, A286) 
• Alloy steel 
• Inconel 
• Monel 
• Brass 

Material, plating and finish requirements are usually defined in the part specification. 

18. How do I know if the metal meets DFARS requirements?

Only specialty metals are DFARS eligible. DFARS-compliant parts must come with documentation stating the country of melting and manufacturing. 

If you haven’t already, check out the second installment of this series, where questions 9 and 10 explore DFARS and specialty metals in greater detail, including which materials are subject to DFARS requirements. 

19. Can I use a commercial equivalent instead of a Mil-Spec fastener? 

Because some Mil-Spec fasteners may not be available off the shelf and may involve a long lead time, some manufacturers substitute commercial or OEM brand name fasteners for Mil-Spec parts. Proceed with caution when using functional equivalents for Mil-Spec fasteners and make sure to first get approval from your engineering or quality team. Functional equivalent commercial versions of MIL-STD fasteners may not have full traceability or certification and may not have passed the rigorous testing required of Mil-spec hardware.  

20. What is a “functional equivalent” fastener?

A functional equivalent fastener matches the form, fit, and function of a Mil-Spec or OEM branded part but may not be manufactured to the same certifying standard or with the certified paperwork available with Mil-Spec hardware. These are often used for commercial or non-critical applications. 

21. How do I cross-reference a Mil-Spec fastener to a commercial or OEM part? 

Start by referring to our cross-reference charts via the link below. Alternatively, provide us with the Mil-Spec number, size, material, any special features, and we’ll identify equivalent options from brands like Holo-Krome, PIC-Design, Alcoa or others. 

Lessons learned: Mil-Spec fastener sourcing, hardware types, materials, and equivalents.

Mil-Spec sourcing isn’t just about finding the right part numbers; it’s about aligning specifications, material, availability, and documentation upfront, so you avoid delays, compliance gaps, and last-minute surprises.  

Buyers need to know where to locate reliable specifications and catalogs, understand which hardware is actually available under Mil-Spec systems, recognize the common material options used in military supply chains, and carefully evaluate whether a commercial or OEM functional equivalent is appropriate or risky. 

Key takeaways: 

• Validate the hardware type: Similar-looking parts numbers (NAS1805 a nut vs. NAS8105 a screw) across hardware categories are not interchangeable.  
• Availability drives decisions: Many Mil-Spec parts are not stocked; lead times and minimums can dictate your options. Plan accordingly. 
• Use cross-referencing strategically: The right equivalent can reduce cost and lead time without sacrificing performance, if done correctly.  
• Define paperwork requirements upfront: If certifications like Manufacturer’s Certificate of Conformance, Material Test Reports, Plating Test Reports or DFARS aren’t requested at quote/PO, don’t expect them later. 

Next up (Part 4): In our next and final installment, part four, we’ll round out the series with reverse cross-referencing (commercial/OEM to Mil-Spec), realistic lead times (including long-lead materials), buying in small quantities, common finishes, and what to do when parts fail inspection.  

In the meantime, if you have any questions, feel free to connect with our team or send us a request for a quote and our team of sourcing experts will help you find what you need. “Finding the right screw for you” is our tag line after all! 

Related:  

• Top 27 Mil-Spec Fastener Questions & Expert Answers Part 1 (Blog)
• Top 27 Mil-Spec Fastener Questions & Expert Answers Part 2 (Blog)
• Buyer’s Guide to Mil-Spec Fasteners  
• Mil-Spec DFARS!? What the heck is that?
• Mil-Spec Fasteners Guide: Frequently Asked Questions

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• Cost-Effective Functional Equivalents to OEM Brand Fasteners-Why Pay More? – Reduce lead times and costs with the same quality and same performance.  Try us for alternatives to brands like McMaster-Carr, MSC, Misumi, PEM, and RAF and experience unmatched savings! Same form, fit and function for less.  
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MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 

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