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 2 of 4) 

Posted: February 24, 2026 | Author: | Filed under: DFARS, Domestic Fasteners, Mil-Spec Fasteners | Tags: , , , , , , , , | Leave a comment
Top 27 Mil-Spec Fastener Questions & Expert Answers Part 2

Welcome back to our 4-part series on Mil-Spec Fastener Questions and Expert Answers.  In part one, we covered what makes a fastener truly Mil-Spec. In Part 2, we focus on Mil-spec fastener compliance, certifications, and documentation.  

In this installment, we break down DFARS and specialty metals, qualifying countries, certification and COC requirements. We also cover when additional documentation must be requested, how to interpret Mil-Spec part numbers, and where to obtain official prints and supporting documentation, the practical checkpoints in the life of a Mil-Spec fastener.

Part 2 – DFARS Specialty Metals, COCs/MTRs & Compliance Paperwork

8. What does DFARS compliance mean? 

DFARS (Defense Federal Acquisition Regulation Supplement) compliance means that the specialty metals used in the fasteners are sourced and manufactured from approved countries. DFARS is often required for Defense Department related contracts. 

9. What materials are DFARS-eligible?

DFARS only pertains to fasteners made from “specialty metals” including stainless steel, high alloy steel, like Grade-BD, or Grade 5 Chromium steel with high chromium content. “Specialty metals” means: 

  1. Steel:
    • With a maximum alloy content exceeding one or more of the following limits:  
      • 1.65% Manganese 
      • 0.60% Silicon 
      • 0.60% Copper 
  1. Metal alloys consisting of: 
    • Containing more than 0.25% of any of the following elements:
      • Aluminum
      • Chromium
      • Cobalt
      • Molybdenum
      • Nickel
      • Niobium (Columbium)
      • Titanium
      • Tungsten
      • Vanadium
  1. Titanium and titanium alloys
    • Nickel or iron-nickel alloys that contain a total of alloying metals other than nickel and iron in excess of 10%.
    • Cobalt alloys that contain a total of alloying metals other than cobalt and iron in excess of 10%. 
  1. Zirconium and zirconium alloys 

“Steel” means an iron alloy that includes between .02 and 2 percent carbon and may include other elements. 
 
Restriction: Except as provided in paragraph (c) of this clause, any specialty metals incorporated in items delivered under this contract shall be melted or produced in the United States, its outlying areas, or a qualifying country. 

10. More about DFARS

Almost a decade ago, the term “DFARS Compliant Material” came to the forefront for companies supplying parts and services to the government. The original Federal Acquisition Regulation (FAR) clause 252.225-7014 specified “A Preference for Domestic Specialty Metals.”  What that means in our world is that for fasteners to be DFARS compliant, the metal used to fabricate them must be melted or manufactured in the United States or a qualifying country. 
 
Qualifying countries: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Egypt, Finland, France, Germany, Greece, Israel, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, United Kingdom of Great Britain and Northern Ireland. Visit the DPC website, section 252.225, or the ACQ website to keep up to date with DFARs requirements, which were updated January 2023. To learn more about DFARS as it pertains to Mil-Spec fasteners, refer to this link. 

11. How do I know if a fastener is Mil-Spec certified?

Mil-Spec fasteners are commonly supplied with a manufacturer’s Certificate of Conformance (COC) referencing the part number which calls out the standard the fastener is made to. 

12. What paperwork comes with Mil-Spec fasteners?

Although Mil-Spec fasteners are commonly provided with the Manufacturer’s Certificate of Conformance (COC), other paperwork such as Material Test Report (MTRs), Plating or Heat Treatment Certifications, DFARS certification, Lot traceability or Dimensional Test reports may also be available and sometimes involve a fee.

Here is a more extensive list of paperwork that might accompany Mil-spec fasteners:

  1. Manufacturer’s Certificate of Conformance (COC) 
    • Verifies that the parts meet the specified Mil-Spec standard 
    • Should include part number, lot number, specification, and manufacturer info 
  2. Material Test Reports (MTRs) (if required) 
    • Confirms the chemical and mechanical properties of the raw material 
    • Typically needed for DFARS compliance or aerospace contracts
  3. DFARS Compliance Statement (if applicable) 
    • Required if your project is subject to DFARS specialty metals clause 
    • Should confirm country of melt and manufacture is DFARS-approved 
  4. Plating or Finish Certifications (if applicable) 
    • Certifies any surface treatments (e.g., cadmium, zinc, passivation) meet required specs 
  5. Heat Treat Certification (for heat-treated parts) 
    • Confirms the heat treatment process meets the Mil-Spec requirements 
  6. Dimensional or Inspection Reports (on request or for critical parts) 
    • Documents that parts were inspected and meet dimensional tolerances 
  7. Lot Traceability 
    • Ensures all fasteners in your order can be traced back to the original manufacturing lot 

13. How do I read a Mil-Spec part number?

Each character in the part number provides information about the size, material, thread, and finish. For example, MS24693C4, sometimes expressed MS24693-C4 or MS24693C-4 is a 4-40 x 3/8 Phillips Flat 100 Degree Machine Screw in 300 Series Stainless Steel. Contact us if you need help decoding a part number! 

14. Where can I get a print of a Mil-Spec part number?

Documentation for MIL-STD parts are maintained by the Defense Logistics Agency (DLA). The Aerospace Industries Association (AIA) has a database of prints available for purchase. 

The fastest way to avoid delays is to align documentation requirements up front, especially when DFARS applies or when your flowdown calls for more than a standard COC. 

Lessons learned: Mil-spec fastener compliance, certifications, and documentation.

Material test reports, plating/finish certs, heat-treat certs, dimensional/inspection reports, and lot traceability can be available, but they often need to be explicitly requested, and sometimes also carry added cost, so it’s smart to define that scope before release and ensure all needed documents are included during your receiving process. 

In our next installment, Part 3, we’ll shift from compliance to sourcing strategy: where to find Mil-Spec catalogs/specs, what types of MIL-STD hardware are commonly used, which materials show up most, and how to think about functional equivalents and cross-referencing without compromising requirements.   

In the meantime, if you have any questions, feel free to Connect withour team or send us a request for 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:  

Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

MF Supply Work With Us

Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply

  • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
  • 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.  
  • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
  • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
  • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  

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. 

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 1 of 4) 

Posted: January 28, 2026 | Author: | Filed under: DFARS, Domestic Fasteners, Mil-Spec Fasteners | Tags: , , , , , , | Leave a comment
Mil-Spec Fasteners | MF Supply

At MF Supply, we specialize in sourcing and delivering certified Mil-Spec fasteners governed by MIL-STD requirements established by the US Department of Defense (DOD) and administered by the Defense Logistics Agency (DLA).   

Mil-Spec hardware isn’t just “stronger” or “higher quality.” It’s manufactured, tested, inspected, and documented to ensure repeatable performance, exacting paperwork and audit-ready compliance, lot after lot, program after program. Strength, dimensions, materials, finishes, inspection criteria, and documentation are all defined long before a part ever reaches production. 

For aerospace, defense, and precision manufacturers, the wrong interpretation of a part number, finish, or country-of-origin requirement can lead to compliance issues, production delays or worse.  

That’s why we’ve compiled answers to the most common/frequent Mil-Spec fastener questions we hear from engineers, program managers, and procurement teams every week. The questions that surface during design, procurement, supplier audits, alternates approvals, and “why did this part get rejected?” moments. 

In Part 1 of this four-part series, we cover the fundamentals: 

  • What actually makes a fastener truly Mil-Spec 
  • How Mil-Spec compares to commercial hardware (with a real-world example) 
  • The most common standards you’ll encounter (AN, MS, NAS/NASM) 
  • How to quickly identify a Mil-Spec part number 
  • What “Made in the USA” does, and does not, mean in practice 

Think of this as the foundation, before alternates are approved, or auditors start asking uncomfortable questions.

Part 1

1. What is a Mil-Spec fastener? 

Mil-Spec (Military Specification) fasteners or MIL-STD fasteners are hardware components that meet specific standards set by the US Department of Defense (DOD). These fasteners are used in critical military, aerospace, and defense applications where reliability, traceability, and performance are essential. 

2. What makes a fastener “Mil-Spec”? 

A fastener is considered “Mil-Spec” when it meets strict US military standards for tensile strength, hardness, material, plating, dimensions, quality, and performance. These fasteners are made to precise specifications, often with specialized coatings, and must pass rigorous testing and inspection. They come with full traceability and certification to ensure reliability in mission-critical applications. True Mil-Spec fasteners are produced only by approved manufacturers and backed by documentation. 

3. What is the difference between Commercial and Mil-Spec Fasteners? 

Mil-spec fasteners look a lot like their civilian/commercial cousins, but these little guys are made to specific standards that define in detail the fasteners’ attributes, including dimensions, tensile strength, hardness, threads, drive type, material qualities, plating/finish, and more. Mil-spec fasteners are even traceable by lot to designated manufacturers. The Qualified Suppliers List for Manufacturer’s [QSLM] is a government-maintained list of Manufacturers certified to make Mil-Spec fasteners according to the highest quality standards—commercial fasteners are not held to such specific and exacting standards. 

4. Do Mil-Spec fasteners have different features and standards than commercial fasteners? 

Mil-Spec parts are manufactured and tested to strict military standards to ensure performance and reliability. In general, commercial fasteners will not have the exact same quality standards. Let’s look at a specific example and compare the Mil-Spec MS24693-C4, (sometimes referred to as MS24693C4 or MS24693C-4) which is a 4-40 x 3/8 Phillips flat 100 degree machine screw in 300 series stainless steel, to its commercial cousin. 
 
Features of MS24693C-4: 

  • Manufactured in a QLSM approved factory 
  • Made/melted in the USA or other DFARs* approved country 
  • Materials to procurement spec FF-S-92, SAE AIR 4127 
  • Cleaned, descaled, passivated to AMS-QQ-P-35; AMS 2700 
  • Dimensions, tensile, hardness, threads, recess, head marking to AN, MS, NAS, NASM standards 
  • Magnetic permeability to test specs ASTM A342 
  • Quality Assurance to procurement spec FF-S-92 MIL-STD 1312 
  • Inspection system requirements per Mil-I-45208 
  • Full lot traceability, manufacturer’s certification, chemical and physical certification
  • Available in diameters from #0 through 1/4 inch in coarse and fine thread and various lengths  

Features of 4-40 x 3/8 commercial Phillips flat 100 degree machine screws in 18-8 series stainless steel:  

  • Manufactured per ASME B18.6.3-2002 
  • Thread dimensions per ASME B1.1 

As you can see, the Mil-spec version is held to a higher and more exacting level of quality and testing than the commercial version.  As such, the Mil-spec parts are cleaned and passivated, and tested for magnetic permeability, whereas the commercial parts don’t have this requirement. 

5. What are the most common Mil-Spec standards? 

The most common Mil-Spec fastener designations include: 

  • AN – Army/Navy Aeronautical
  • MS – Military Standard 
  • NAS & NASM – National Aerospace Standard  

6. How can I identify a Mil-Spec fastener? 

Look for part numbers starting with MS, NAS, or AN, which indicate the applicable standard. 

7. Are Mil-Spec fasteners always made in the USA? 

Not necessarily. However, fasteners required to meet DFARS compliance must be made from specialty metals that are melted and manufactured in qualifying countries, including the USA. 

If you take only one thing from these first seven questions, let it be this: true Mil-Spec fasteners are produced only by approved manufacturers and backed by documentation.  And while “USA-made” is sometimes assumed, DFARS requirements are tied to specialty-metal sourcing/melt and qualifying countries, not a blanket label, so it’s worth confirming early.  In Part 2, we’ll go deeper on DFARS, specialty metals, and the documentation stack (COCs, MTRs, plating/heat-treat certs, inspection reports) that often determine whether parts pass review.  

In the meantime, if you have any questions, feel free to Connect with our team or send us a request for 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:  

Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

MF Supply Work With Us

Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply

  • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
  • 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.  
  • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
  • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
  • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  

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. 

Case Study: Avoiding a 26-Week Delay with Stocked DFARS Screws

Posted: December 16, 2025 | Author: | Filed under: DFARS, Domestic Fasteners, keensert, key-locking inserts, Mil-Spec Fasteners, Socket Head Cap Screw, Socket Products | Tags: , , , , , , , , , , , , , , , | Leave a comment

A Buyer’s Case Study on Compliance + Speed

If you sell into the defense or aerospace industry, “finding a screw” is never just finding a screw. The part has to be dimensionally and chemically correct and compliant, with the documentation to prove it. 

This is where many procurement teams get stuck: the hardware exists, but the paper trail doesn’t… or the lead time blows up the schedule. 

The MF Supply Value Proposition

If you have a commercial part on a BOM that now needs DFARS / Buy American + documentation, MF Supply helps you do one of two things: 

  1. Convert the requirement into the correct Mil-Spec / spec-controlled equivalent (form/fit/function + compliance + paperwork). 
  1. Source or produce a DFARS-compliant version of a commercial catalog part with shorter lead times and with the right cert package. 

You get the part you need, on time, with the compliance paperwork you need without playing supplier roulette.

What DFARS/Buy American Actually Means for Fasteners 

For fasteners made from specialty metals (including many stainless and high-alloy steels), DFARS requires qualifying melt/manufacture origin. But the “gotcha” is simple:  If you can’t document it, it doesn’t count. 

Typical documentation packages include: 

  • Manufacturer Certificate of Conformance (COC) 
  • Country-of-origin / DFARs specialty metal compliance statements 
  • Material Test Reports (MTRs)

Visit the DPC website, section 252.225, to keep up to date with DFARs requirements, which were updated January 2023. Click here and scroll to 7009 for more information: 252.225-7000 Buy American Act – Balance of Payments Program Certificate.

The Challenge: Compliant Part, Short Lead Time, Complete Documentation

Many “available” fasteners on the market are: 

  • Not DFARS compliant
  • Not available with COC/MTR 
  • Not stocked (or stocked without the right chain-of-custody), leading to long lead times  

The Situation: “We Need It Now… and It Needs To Pass Audit.”

A manufacturer supporting a defense aerospace assembly needed a 10-32 x 3/4 socket head cap screw in 300-series stainless. The Bill of Materials (BOM) required: 

  • DFARS-compliant specialty metal
  • Manufacturer COC  
  • MTRs / test reports 
  • Documented material origin 

Their incumbent supplier quoted 26–30 weeks. That was a hard no. 

The Solution: Cross-Reference to an In-Stock Mil-Spec Option (With Paperwork)

The buyer searched for DFARS-compliant 10-32 x 3/4 socket head cap screws in stainless steel and landed on MF Supply’s product page for: NAS1351C3-12 (10-32 x 3/4) Mil-Spec socket head cap screw, stainless, DFARS 

MF Supply worked with the buyer to: 

  • Confirm the correct spec-controlled requirement  
  • Pull active inventory from a qualified supply chain 
  • Provide COC + MTR documentation 
  • Confirm DFARS specialty metal origin with documentation

The result 

  • 26+ week production delay avoided 
  • Compliance risk eliminated 
  • Audit-ready paperwork shipped with the order 

When Cross-Referencing Helps (And When It Doesn’t)

Cross-referencing can reduce lead times and risk when it’s validated upfront: 

  • Form/fit/function confirmed 
  • Spec requirements verified (AN/MS/NAS/NASM, etc.) 
  • Documentation requirements confirmed (COC, MTR, COO/DFARS statements) 

Substitution only works when the part and the paperwork both match the requirement. 

Buyer Takeaway: In-Stock + Paperwork=Shorter Lead Times, No Surprises

If your customer needs DFARS / Buy American compliance, always ask: 

  • Can you provide a COC?
  • Can you provide DFARS specialty metal documentation?  
  • Is material origin documented? 
  • Is it in stock, or are you quoting a 20–30 week lead time? 

At MF Supply, inventory is backed by documentation, so you don’t have to choose between speed and compliance. 

Need DFARS-compliant screws fast and with paperwork? 

Send your part number, drawing, or BOM requirements. We’ll confirm the right spec, validate compliance, and quote the fastest safe path. 

And yes, “finding the right screw for you” isn’t just our tagline. It’s our favorite sport. 

Related:  

Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

MF Supply Work With Us

Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply

  • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
  • 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.  
  • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
  • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
  • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  

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. 

Mastering Mil-Spec Dowel Pins: Fit, Material, and Series Made Simple

Posted: October 28, 2025 | Author: | Filed under: dowel pin, M21143, Mil-Spec, Mil-Spec Fasteners, Mil-Spec Precision Dowel Pins, MS16555, MS16555, MS16556 and Mil-P-21143., MS16556, PRECISION DOWEL PIN | Tags: , , , , , , , , , , , , , | Leave a comment
Precision Dowel Pins at MF Supply

What Makes Mil-Spec Dowel Pins Different? 

Mil-Spec (Military Standard) dowel pins are precision-ground, solid headless fasteners engineered for exact alignment, location, and secure assembly of components in aerospace, defense, and precision manufacturing. 

They are produced under strict Mil-Spec specifications to ensure dimensional accuracy, repeatability, and conformance.  Unlike commercial pins, Mil-Spec versions must be tested and certified for mechanical properties, hardness, and finish supported by documentation packages that may include Material Test Reports (MTRs), Certificates of Conformance (COCs), Heat Treat Certifications and DFARs compliance statements. 

Dowel pins are commonly used as hinges, shafts, pivots, or locating devices to align or secure parts within precision assemblies or fixtures. 

Four Common Mil-Spec Dowel Pin Series 

Not all dowel pins are created equal. Each Mil-Spec series follows strict guidelines for fit, tolerance, material and other attributes to ensure accuracy and repeatability in demanding applications. Whether double-chamfered or featuring a radius and chamfer combination, these pins play a vital role in precision alignment. Below we deconstruct the taxonomy and attributes of the four series most frequently used in military and aerospace manufacturing. 

1 – MS16555 — Standard Headless Dowel Pin (Press Fit) 

Equivalent: Similar to ASME B18.8.2 standard series 

  • Design: Straight, solid headless dowel pin normally made with a chamfered crown on one end and a chamfer on the other 
  • Fit Type: Provides a standard interference/press fit 
  • Tolerance: -0 / +0.0002 over nominal size 
  • Material Options: 
    • MS16555-1 to -145: Steel (Carbon or Alloy), hardened
    • MS16555-301 to -444: Phosphate-coated Steel, hardened
    • MS16555-601 to -744: CRES 410/416 Stainless Steel, hardened and passivated
  • Diameter Range: 1/16″ (.0626–.0628) to 1″ (1.0001–1.0003) 
  • Length Range: 3/16″ to 6″ (lengths over 3″ may be limited) 
  • Applications: Ideal for vibration-resistant, high-strength alignment in aircraft and defense assemblies

➡️ Available for purchase online or RFQ

2 – MS16556 — Oversize Headless Dowel Pin (Extended Length / Oversize Fit) 

Equivalent: Similar to ASME B18.8.2 oversize standard series 

  • Design: Straight, solid headless dowel pin normally made with a chamfered crown on one end and a chamfer on the other (Similar to MS16555 with oversize tolerance) 
  • Fit: Oversize interference fit  
  • Tolerance: -0 / +0.001 over nominal diameter 
  • Material Options: 
    • MS16556-1 to -144: Steel (Carbon or Alloy), hardened
    • MS16556-301 to -444: Phosphate-coated Steel, hardened
    • MS16556-601 to -744: Stainless Steel, hardened and passivated
    • MS16556-801 to -944: Cadmium-plated Steel, hardened
  • Diameter Range: 1/16″ to 1″ 
  • Length Range: 3/16″ to 6″ (extended per spec; over 3″ limited) 
  • Applications: Ideal for worn holes and to replace pins that no longer fit securely. 

➡️ Now available for RFQ at mfsupply.com

MIL-P-21143 Series 

3 – M21143/1 — CRES 303 Stainless Steel Dowel Pin (Press Fit) 

Specification: MIL-P-21143 

  • Design: Straight, headless pin with .015/.010 x 45° chamfer on both ends 
  • Fit: Press fit — standard interference fit (referred to as “Oversize” in spec) 
  • Tolerance: -0 / +0.0002 over nominal 
  • Material: CRES 303 Stainless Steel 
  • Diameter Range: 1/16″ to 1″ 
  • Applications: Used to join moving components or in high-precision assemblies requiring corrosion resistance and tight alignment 

➡️ Available for RFQ at mfsupply.com

4 – M21143/2 — CRES 303 Stainless Steel Dowel Pin (Slip Fit / Undersize) 

  • Design: Produced similar to M21143/1, straight, headless dowel pin with precision-ground surfaces, generally produces with a .015/.010 x 45° chamfer both ends 
  • Fit: Slip fit — slightly undersized for easy removal or adjustment 
  • Tolerance: +0 / -0.0002 under nominal diameter 
  • Material: CRES 303 Stainless Steel. 
  • Applications: Used in assemblies requiring frequent disassembly or maintenance; ideal for prototypes or variable-fit applications 

➡️ Available for RFQ at mfsupply.com

Choosing the Right Material 

Material Key Traits Common Uses
Alloy/Carbon Steel (Plain, Cadmium, Phosphate) High strength, durable Heavy-load or high-temp applications 
CRES 410/416 Stainless Steel Hardened, corrosion-resistant Aerospace and defense 
CRES 303 Stainless Steel Corrosion-resistant, easy to machine Slip-fit and/or precision alignment 

All Mil-Spec dowel pins from MF Supply include Manufacturer’s Certificates of Conformance. Full certification packages — MTRs, Dimensional Reports, Heat-Treat, Passivation, and DFARS statements — are available upon request and may incur a fee. 

👉 Checkout our Mil-Spec Precision Dowel Pins Cross-Reference Charts

Checklist: Sourcing the Correct Mil-Spec Dowel Pin 

Before placing your RFQ or order, confirm: 

  1. Specification / Part Number – e.g., MS16555, MS16556, M21143/1, M21143/2.  Check the diameter, length, tolerance, material and all specs to the Mil-Spec print. 
  2. Material & Finish – Match environment and strength needs. 
  3. Fit / Tolerance – Choose standard press fit, oversize, or slip fit as required. 
  4. Documentation – Determine your paperwork requirements at every stage of the process from initial RFQ to receiving inspection to insure audit readiness. 

Mil-Spec Dowel Pins from MF Supply 

MF Supply is your WBE/WOSB-certified U.S. distributor for certified, commercial, and custom dowel pins, including: 

  • MS16555, MS16556, M21143/1, and M21143/2 series 
  • Alloy and CRES Stainless Steel options 
  • Certification packages (MTRs, COCs, Passivation, DFARS, Heat-Treat) 
  • Fast RFQ turnaround and domestic stock for quick delivery 
  • Made to order option for parts that are not COTs or for special sizes, materials and tolerances 

We’re proud to announce that MS16556 dowel pins are now available for RFQ — joining our comprehensive Mil-Spec, metric, and precision dowel pin lineup. 

👉 Visit MF Supply to request a quote or browse our catalog.

We are your Purchasing Department’s Secret Weapon for Mil-Spec hardware! 

Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

MF Supply Work With Us

Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply

  • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
  • 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.  
  • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
  • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
  • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  
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.  

Mil-Spec Socket Cap Screws: A Complete Buyer’s Guide

Posted: September 22, 2025 | Author: | Filed under: Mil-Spec, Mil-Spec Fasteners, MS16995, MS16996, MS16997, MS16998, MS24671, NAS1351, NAS1352, Socket Head Cap Screw | Tags: , , , , , , , , , , , , , , , | Leave a comment

When it comes to aerospace, defense, and mission-critical industrial applications, not all socket cap screws are created equal. While commercial socket cap screws can be sufficient for general manufacturing, Mil-Spec socket cap screws are engineered, tested, and certified to meet the stringent requirements of the U.S. military and defense supply chain.

In this guide, we’ll cover:

  • The variations of Mil-Spec socket cap screws
  • Materials, platings, and optional features
  • The part number taxonomy (MS, NAS, NASM, AN designations)
  • How Mil-Spec differs from commercial socket caps
  • Typical applications and industries
  • MF Supply’s Mil-Spec socket cap screw catalog offerings

Variations of Mil-Spec Socket Cap Screws

Mil-Spec socket cap screws (sometimes called MS or NAS socket head cap screws) come in multiple variations to meet specific performance requirements: The 2 main Mil-Spec standards are:  

  • Standard socket head cap screws – Cylindrical head, hexagonal drive. Designed for high-strength fastening where space is limited. 
  • Flat socket cap screws – Used in clearance-sensitive applications where flush mounting is critical. 

Note: Low Head and Button Head socket cap screws do not have a Mil-Spec equivalent. 

Mil-Spec socket head cap screws come in several varieties, including: 

  • Drilled heads (safety wire holes) – Feature cross-drilled holes in the head to allow safety wiring, preventing loosening in high-vibration environments like aircraft engines. 
  • Thread-locking (pre-applied patch) – Includes a nylon or chemical locking element on the threads, providing resistance to vibration loosening. 
  • Vent/drilled-through screws – Designed to eliminate trapped gas or contamination in vacuum or cleanroom environments. 

Note: Varieties including threadlocking, drilled heads and vented options are less common and may only be available per special order with minimums and lead times. 

Materials & Platings

Mil-Spec socket cap screws are offered in specific materials and platings with mechanical properties that meet or exceed ASTM/SAE standards. Common options include: 

  • Alloy Steel – High tensile strength, black oxide or cadmium plated for corrosion resistance 
  • CRES Stainless Steel (18-8/300 series stainless steel) – Corrosion resistance, often used in aerospace and marine environments 
  • CRES A286 Stainless Steel superalloy – Extreme temperature resistance, high strength and with excellent corrosion & oxidation resistance 

Note: SS316 stainless steel is less common and may only be available by special order with minimums and lead times. 

Platings and Coatings: 

  • Black Oxide (MIL-C-13924, Class 1) – Standard corrosion resistance 
  • Cadmium Plating (QQ-P-416) – Excellent corrosion resistance and lubricity. Widely specified in legacy Mil-Spec standards. 
  • Passivation (for stainless steels, QQ-P-35) – Removes surface contaminants and improves corrosion resistance. 

Part Number Taxonomy

Military grade fasteners or “Mil-Spec” fasteners are usually designated by an AN, MS, NAS or NASM prefix followed by a part number.  Each of these prefixes is an abbreviation: NAS stands for National Aerospace Standard and MS stands for Military Standard. 

The Defense Supply Center Philadelphia (DSCP), part of the DLA (Defense Logistics Agency), has a Qualified Suppliers List for Manufacturers (QSLM) identifying pre-qualified sources for certain products purchased by DSCP. Referred to also as the QPL (Qualified Products List), manufacturers on this list are recognized by DSCP as meeting all necessary criteria, particularly regarding quality control and paperwork.

Each part number defines key parameters: head style, material, finish, thread class, and whether features like drilled heads or locking elements are included.

The main core part numbers identifying standard Mil-Spec socket head cap screws are MS16995, MS16996, MS16997, MS16998, NAS1351, and NAS1352. Flat head socket head cap screws fall under parts MS24671 and MS24672.

  • MS (Military Standard) – Legacy part numbers (e.g., MS16995), still widely used in aerospace and defense
  • NAS (National Aerospace Standards) – High-performance standards developed for aerospace (e.g., NAS1351, NAS1352)
  • NASM – Updated versions of NAS standards under SAE governance
  • AN (Army-Navy) – Older standards, often superseded by MS or NAS numbers

The base part is followed by a Material Code:

  • “-” = Alloy Steel 
  • “C” = Corrosion Resistance Steel (18-8 stainless steel) 
  • “N” = Heat-Resistant Steel (A286) 
  • Let’s further break down a common Mil-Spec socket cap: 
  • For example: NAS1352N028, sometimes written as NAS1352N02-8 
  •  2-56 X 1/2 Mil-Spec Socket Head Cap Screw A286 Stainless Steel DFAR 
  • NAS1352 = Coarse thread Socket Head cap screw 
  • N = Heat-Resistant Steel (A286) 
  • 02 = 2-56 Diameter 
  • 8 = .500 or 1/2 screw length 

Note: The Aerospace Industries Association maintains an updated list of NAS parts available to members and/or for purchase. 

Why Mil-Spec Socket Caps Are Different from Commercial

Commercial socket caps may look identical to Mil-Spec socket caps.  However, commercial fasteners may lack the controlled processes, documentation, and certifications required for military or aerospace projects.   

Differences between Mil-Spec and commercial socket head cap screws may include: 

1. Certification & Paperwork 

Available Paperwork may include:  

  • Manufacturer’s Certificate of Conformance (C of C) 
  • Lot and heat traceability 
  • Dimensional testing 
  • Material Test Reports (MTRs) 
  • DFARS compliance certification for defense projects 

2. Testing 

Mil-Spec socket caps undergo rigorous mechanical, dimensional, and sometimes nondestructive testing to verify hardness, tensile strength, shear strength, plating thickness, and more. 

3. Authorized Manufacturers 

Manufacturers listed on the QPL (Qualified Products List), the Qualified Suppliers List for Manufacturers (QSLM), or those approved under aerospace quality systems (AS9100, NADCAP for plating, etc.) are authorized to produce Mil-Spec socket caps. This ensures supply chain integrity and reliability in defense applications. 

Applications

Mil-Spec socket head cap screws are commonly used in: 

  • Aerospace & Defense – Aircraft structures, engines, avionics, and ground support equipment 
  • Military Vehicles & Marine – Tanks, ships, submarines, and defense electronics 

Other industries use Mil-Spec fasteners because of their quality and traceability.  Two examples include Precision Manufacturing where vibration, temperature extremes, or strict compliance require certified fasteners, and Medical & High-Tech Industries where cleanrooms, vacuums, or corrosive environments require traceability is essential. 

MF Supply’s Mil-Spec Socket Cap Offerings 

At MF Supply, we stock and source a broad catalog of Mil-Spec socket head cap screws including: 

We partner with only qualified U.S. and global manufacturers and provide full certification packages upon request. 

Beyond strength and performance, the real differentiators are the certifications, testing, and compliance requirements that ensure supply chain integrity. 

MF Supply has over 50 years of experience supplying Mil-Spec, DFARS-compliant, and certified hardware. Whether you need a handful of parts or long-term stocking solutions, we’re Your Purchasing Department’s Secret Weapon. 

👉 Explore Our Catalog of Mil-Spec Socket Cap Screws or Request a Quote today.

Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

MF Supply Work With Us

Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply

  • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
  • 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.  
  • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
  • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
  • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  
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.  

MF Supply Recertified as a Small Woman-Owned Business Enterprise!

Posted: January 22, 2025 | Author: | Filed under: Custom Fasteners per print, Domestic Fasteners, Electronic Hardware, Fasteners, Mil-Spec Fasteners, Panel Fasteners, Supply chain - manufacturing | Tags: , , , , , , , , , , , , , | Leave a comment

MF Supply, a leading distributor of fasteners and hardware, is proud to announce that we have successfully been recertified as a Women’s Business Enterprise (WBE) and Small Business Enterprise (SBE) by the state of New Jersey. This certification reaffirms MF Supply’s commitment to providing high-quality products while fostering diversity and inclusion in the manufacturing and distribution sectors.

      How Does This Benefits You

      • Meet Your Diversity Goals: As a certified WBE and SBE supplier, we can help your business fulfill inclusion and diversity requirements while ensuring top-tier service and reliability.
      • Hard-to-Find Parts? Solved! From mil-spec fasteners to custom hardware, we specialize in sourcing hard-to-find components like Keensert® style key-locking inserts, helical inserts, dowel pins, socket head cap screws and more—all with precision and speed.
      • Decades of Expertise: Partner with a team that understands your needs. Whether it’s aerospace engineering, manufacturing, or government projects, we act as an extension of your purchasing departments providing lightning-fast responses, direct support, and competitive pricing.

      Why Choose MF Supply?

      With 50 years of fastener experience, we offer lightning-fast responses, direct phone support, free samples, and act as an extension of your team. We are fastener & sourcing experts, so you don’t have to be. With vast experience as a leading supplier and distributor of commercial and Mil-Spec fasteners, both in inch and metric sizes, we excel in providing:

      Featured Products:

      Some of our featured product lines include:

      1. Keensert® Style Key-Locking Inserts
      2. Helical Inserts (aka HeliCoil®)
      3. Precision Dowel Pins
      4. Precision Shoulder Screws
      5. Socket Head Cap Screws
      6. Other Socket Products
      7. Standoffs & Spacers
      8. Mil-Spec Fasteners
      9. Custom-made and reworked hardware and components

      Manufacturers working with us can expect timely deliveries, competitive pricing, and access to expert guidance to help optimize their fastener choices. Visit our website, Connect with our team or send us a request for 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!

      Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

      MF Supply Work With Us

      Your Purchasing Department’s Secret Weapon!
      Here are 5 reasons to buy from MF Supply

      • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
      • 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.  
      • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
      • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
      • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  
      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.  

      Mil-Spec Fasteners in Stock at MF Supply

      Posted: November 27, 2024 | Author: | Filed under: Mil-Spec, Mil-Spec Electronic Hardware, Mil-Spec Fasteners | Tags: , , , , , , , , , , , , , , | Leave a comment

      Are you searching for certified Mil-Spec fasteners to meet your bill of requirements (BOM) or project specifications? Look no further! MF Supply specializes in sourcing and supplying domestically manufactured AN, MS, and NAS Mil-Spec fasteners for aerospace, defense, and industrial applications. MF Supply stocks over 3,000 unique certified parts from the Qualified Suppliers List for Manufacturers & Distributors (QSLM & QSLD). Mil-Spec products stocked include Keensert® Style Key-Locking Inserts, Helical (HeliCoil®) Inserts, Precision Dowel Pins, Slotted Spring Pins, Extended Prong Cotter Pins, Nuts, Washers, Machine Screws, Precision Shoulder Screws, Hex Head Cap Screws/Bolts, Socket Head Cap Screws, Set Screws, Self-Tapping Screws and more. All Mil-Spec parts undergo rigorous testing and are DFARS or domestically manufactured with Certificate of Conformance (COC) and Material and Physical certification paperwork available to ensure compliance.

      Buy Mil-Spec Fasteners and Precision Electronic Hardware at MF Supply!

      We Have All the Mil-Spec Fasteners and Precision Hardware You Need

      We offer a huge selection of DFARS certified and domestic Mil-Spec fasteners directly on our website, making it easier for you to find exactly what you need for your project at the click of a button or via RFQ depending on your preferred method of procurement. Below is a list of some of our most popular Mil-Spec product categories available:

      1 – Mil-Spec Keensert® Style Key-Locking Inserts

      • Standards: MS51830, MS51831, MS51832, NA0146, NA0147, NA0148, NA0149, NA0150, NA0151, and NAS1395.
      • Styles: Miniature, Thin Wall, Heavy Duty, Thick Wall, and Extra Heavy Duty
      • Available Sizes: 2-56 to 1/2-13 Internal thread for inch sizes and M2 x 0.4 to M24 x 2 for metric sizes
      • Materials: 4140 alloy steel, Nitronic 60, CRES A286 and 303 series stainless steel
      • Applications: Can be used to create new threads, for thread reinforcement, and to repair stripped threads

      2 – Helical Inserts (aka HeliCoil®)

      • Standards: MS121, MS122, MS124, MS21209, MA3279, and MA3329
      • Styles: Free-running and self-locking
      • Available Sizes: #2-56 to 1½-6 for inch sizes and M2 to M36 for metric sizes
      • Materials: CRES 300/18-8 stainless steel
      • Applications: Can also be used to create new threads, for thread reinforcement, to convert threads between inch and metric sizes, and to repair stripped threads

      3 – Mil-Spec Precision Dowel Pins

      • Standards: MS16555, MS16556, and MIL-P-21143
      • Styles: Interference/Press Fit, Undersize/Slip Fit and Oversize +.001
      • Sizes: Diameters from 1/32 to 1 inch and lengths from 3/32 to 6 inches
      • Materials: CRES 303, 400, 416 series stainless steel
      • Applications: Can be used as a hinge, shaft, precise location device or pivot to align or secure parts within a precision assembly or fixture

      4 – Mil-Spec Slotted Spring Pins

      • Standards: MS16562
      • Styles: Slotted
      • Sizes: Diameters from 1/16 to ½ inch and lengths from 3/16 up to 3 inches long
      • Materials: Alloy steel with a zinc phosphate finish
      • Applications: Can be used as a hinge or shaft for the purpose of securing and fastening components together

      5 – Mil-Spec Extended Prong Cotter Pins

      • Standards: MS9245
      • Styles: Extended Prong
      • Sizes: Diameters from 1/32 to 5/32 inch and lengths from 1/4 to 1/2 inches long
      • Materials: T321 stainless steel
      • Applications: Designed to retain/secure a variety of fasteners such as bolts, nuts and pins in place and prevent them from sliding or coming out

      6 – Mil-Spec Hex Finished Nuts

      • Standards: MS51967B & MS51967C
      • Styles: Grades B & C
      • Sizes: Stock sizes from 1/4-20 through 3/4-10 inches thread
      • Materials: Alloy steel with a cadmium yellow finish
      • Applications: Used to fasten parts together by pairing and tightly securing bolts in place

      7 – Mil-Spec Hex Machine Nuts

      • Standards: MS35649 & MS35650
      • Available Sizes: Stock sizes from 2-56 through 3/8 thread
      • Materials: Alloy steel cadmium yellow and 300/18-8 series stainless steel
      • Applications: Typically paired with bolts or screws to ensure parts/components stay firmly fastened in place

      8 – Mil-Spec Washers

      • Standards: MS51848, NAS620, MS35333, MS35335, MS35338, AN960, AN960-C, AN970, MS15795, MS27183, NAS1149 & NAS620
      • Styles: flat, light flat, flat machine screw, split lock, high collar split lock, internal tooth lock, and external tooth lock
      • Materials: Carbon steel, Alloy steel and 300/18-8, 316, 400 series stainless steel
      • Applications: Distribute the load of a fastener, such as a bolt or screw, over a larger surface area. This in turn helps reduce the effects of wear, damage or vibration on the fastener assembly by providing a cushion between the fastener head and the parent material

      9 – Mil-Spec Machine Screws

      • Standards: MS24693, MS35190, MS35191, MS35206, MS35207, MS35265, MS35266, MS35275, MS35276, MS51957, MS51958, MS51959, & MS51960
      • Styles: 82d & 100d Flat Phillips, Drilled Slotted Fillister, Philips Pan Head
      • Available Sizes: Diameters range from 0-80 to 3/8-16 inches with lengths ranging from 3/32 to 3 inches long
      • Materials: Carbon steel, Alloy steel, and 300/18-8 series stainless steel
      • Applications: Often used in conjunction with other fastening elements, such as washers and nuts, they have uniform threads that when fastened engage with corresponding threads in a tapped hole or nut, creating a secure mechanical connection between components

      10 – Mil-Spec Precision Shoulder Screws

      • Standards: MS51576 & MS51575
      • Styles: Hex and slotted drives
      • Available Sizes: Stock sizes range from 4-40 to 3/8-16 thread
      • Materials: 300/18-8 series stainless steel
      • Applications: Feature a cylindrical unthreaded shoulder that serves as a dowel or pivot point for rotating parts, also used to hold parts together within a precision assembly

      11 – Mil-Spec Hex Head Cap Screws/Bolts

      • Style: Hex head
      • Standards: MS35307, MS35308, MS90725, MS90726, MS90728G & MS90727F, B1821
      • Sizes: Stock sizes range from 1/4-20 through 1-1/4 diameter
      • Materials: Alloy steel, 300/18-8 Series Stainless Steel
      • Applications: Their hexagonal heads allow for the application of high torque using a wrench or socket, which enables a very tight and secure fastening for load-bearing structures in military vehicles, aircrafts and more

      12 – Socket Head Cap Screws

      • Style: Socket head
      • Standards: NAS1352C / MS16995, NAS1351C / MS16996, MS16997, MS16998, NAS1351N & NAS1352N, & MS24671
      • Sizes: Stock sizes range from 0-80 through 1-1/2 diameter
      • Materials: Alloy steel, 300/18-8 series stainless steel, A286
      • Applications: These screws have a cylindrical head with a hexagonal recess (socket) that allows for tightening with an Allen wrench/hex key. The socket head design allows for use in applications where there is limited space. The hexagonal socket allows for precise control during assembly, ensuring the screw is driven straight and accurately into the desired position

      Can’t find what you’re looking for in the list above? Send us an RFQ with the product description or part number that you are looking for and our MF Supply team of sourcing experts will help find what you need!

      Why Buy Mil-Spec Fasteners from MF Supply?

      When precision, compliance, and reliability are non-negotiable, MF Supply stands out as a trusted partner for mil-spec fasteners. Here’s why industrial buyers across aerospace, robotics, defense, and manufacturing sectors turn to MF Supply:

      Compliance and Certification: MF Supply’s mil-spec fasteners meet stringent U.S. Department of Defense (DoD) specifications, including MS51830, MS51831, and more. Each fastener is available with Material and Physical Test Reports, Certificates of Conformance, and DFARS/Domestic Statements—providing peace of mind for critical applications.

      Sourcing Expertise: MF Supply works with the best factories across fastener categories, offering tailored solutions based on your budget, delivery and certification needs.

      Reliability Across Critical Industries: Serving aerospace, defense, robotics, automotive, and manufacturing sectors for over 50 years, MF Supply is a trusted partner for industries where delivery times, precision and reliability are non-negotiable.

      Shop Over 3,000 Unique Mil-Spec Fasteners and Precision Hardware Directly on Our Website!

      Manufacturers working with us can expect timely deliveries, competitive pricing, and access to expert guidance to help optimize their fastener choices. Manufacturers eager to explore our Mil-Spec products’ catalog, including our other recently expanded product categories, are encouraged to visit our website at www.mfsupply.com, reach out to us at sales@mfsupply.com or request a quote. Our MF Supply team of sourcing experts will help you find what you need. “Finding the right screw for you” is our tag line after all!

      Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

      MF Supply Work With Us

      Your Purchasing Department’s Secret Weapon!
      Here are 5 reasons to buy from MF Supply

      • We Source and Deliver What Others Can’t, Faster Than You Imagined – With speedy solutions for elusive parts and lengthy delivery times – We’ve got you covered with both custom-made specials (send us your prints!) and hard-to-source options, quickly and at a fair price.
      • 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.  
      • Huge Selection of Certified and Commercial Hardware with Same-day Shipping Available for Countless Items – We source and stock standards, specials, commercial, Mil-Spec & OEM brands in inch and metric sizes. Standards include AN, NAS, MS, IFI, ASTM, ASME, DIN, ISO, JIS. We are sourcing experts for inserts, certified Mil-Spec parts and anything in stainless steel. Many parts are available with manufacturers’ certifications, including DFAR, ROHS and CoC. Trust us to ship on-time from our national distribution centers. 
      • A User-Friendly, 24/7 Online Shopping Experience – Enjoy a 24/7 online shopping experience with easy-to-use filters, detailed product information, and a constantly updated technical directory. Sign up now for a seamless experience! 
      • WBE/WOSB Certified Woman-Owned Small Business – As a certified Woman-Owned Small Business, we support your diversity goals. Trust us to meet your fastener and sourcing needs with expertise and efficiency [Cage Code 58QG4].  
      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.  

      Domestic Socket Products at www.mfsupply.com!

      Posted: January 11, 2024 | Author: | Filed under: American Sockets, Blue Devil, Brand equivalents, dowel pin, Fasteners, Inch, Metric, Metric Dowel Pins, PRECISION DOWEL PIN, Socket Head Cap Screw, Socket Products, Socket Set Screws, Socket Set Screws Cone Point, Socket Set Screws Cup Point, Socket Set Screws Flat Point, Socket Set Screws Half-Dog Point, Socket Set Screws Knurled Cup Point, Socket Set Screws Nylon Tip, Socket Set Screws Oval Point | Tags: , , , , , , , , , , , , , , , | Leave a comment

      Greetings to our precision manufacturing community!

      We are reaching out with an important announcement regarding our domestic sockets product lines. As we continuously strive to bring you the best in quality and service, we want to inform you of a significant change in our offerings.

      Did You Know That Blue Devil® Is Now American Sockets?

      Firstly, we want to address a key change: the Blue Devil® brand, a name many of you have come to trust and rely on for your domestic socket products needs, will no longer be produced. This marks the end of an era, but also the beginning of an exciting new chapter.

      We are thrilled to introduce American Sockets – a new brand of domestic socket products! This transition is more than just a change in name; it’s a reaffirmation of our continued commitment to quality and excellence.

      What This Means for You

      • Continuity in Quality and Manufacturing: While the brand name changes, what remains constant is the quality of the products. American Sockets are manufactured by the same esteemed US manufacturers that produced the majority of the Blue Devil products. This ensures that the products you’ve trusted for years will continue to be of the same high standards.
      • Seamless Transition: We understand the importance of consistency in your operations. Rest assured, that this transition from Blue Devil to American Sockets will be seamless, with no compromise in the product quality or variety that you have come to expect.

      Domestic Socket Products at MF Supply

      MF Supply is a WBE/WOSB woman owned business, and leading supplier of Domestic Socket Products including major OEM brands, such as American Sockets, and brand equivalents, in various sizes and materials. We offer options when it comes to made in the USA, DFAR compliant Socket Products. Many of our products are available with Certificate of Conformance and full certifications available upon request.

      Here are links to the American Socket brand of Inch Domestic Socket Product Lines:

      Here are links to the American Socket brand Metric Domestic Socket Product Lines:

      In addition to American Sockets brand Socket Products, we offer a vast choice of socket products, including Mil-Spec, OEM branded, standards and custom made specials. To search for what you need, use our Search bar, then filter by size, material, specification, or other qualities you are seeking. Alternatively, you can check out these handy links to view by category:

      Do you still have questions or would like to speak with a representative? Reach out to us, and our MF Supply team of sourcing experts will help you find what you’re looking for. “Finding the right screw for you” is our tag line after all!

      Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

      MF Supply Work With Us

      Six Reasons To Buy From MF Supply

      • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
      • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
      • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
      • Creatively Solve Problems – We are sourcing experts and specialize in hard to find parts. We offer custom manufacturing and reworking solutions at competitive pricing, reducing long deliveries.
      • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
      • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

      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. 

      Inch & Metric Nitronic Keenserts® Now Available at www.mfsupply.com!

      Posted: November 15, 2023 | Author: | Filed under: Brand equivalents, Fasteners, Inch and Mil-Spec Keensert, keensert, key-locking inserts, Metric Keensert, Nitronic 60 Keenserts, Threaded Bushing, Threaded Fasteners | Tags: , , , , , , , , , , , , , , | Leave a comment

      In the bustling world of manufacturing and engineering, where every component counts and the margin for error is slim, MF Supply recognizes the intricacy involved in sourcing materials that offer both superior performance and extended durability. This is where our friends, the Key-locking Inserts (AKA Keenserts®) become the stars of the show. Today, we’re turning the spotlight on an insert that’s been making waves in the industry: the Nitronic 60 Key-locking Insert!

      If you’re on the quest for Key-locking Inserts that promise to elevate the integrity of your projects, you’re in the right place. Nitronic 60 key-locking Inserts are not just components; they’re your peace of mind molded into high-performance alloy.

      Why Nitronic 60 Key-locking Inserts? The Vanguard of Resilience

      Picture a material that laughs in the face of wear, shrugs off corrosion, and doesn’t flinch under high torque. That’s Nitronic 60 for you — an alloy steel that’s as tough as they come. Crafted from this robust alloy, Nitronic Key-locking Inserts boast unparalleled wear and galling resistance. For those of you constantly battling the wear and tear that comes with mechanical demands, these threaded inserts are your knights in shining armor. Think of them as the silent guardians against the everyday wear-and-tear that can compromise your work.

      The Rust Doesn’t Sleep, But You Can

      Corrosion is the arch-nemesis of metal, lurking and waiting to undermine your structures. But with Nitronic 60’s exceptional corrosion resistance, rest easy knowing that your components are as steadfast as your ambition. Whether it’s the salty bath of marine environments or the demanding conditions of chemical processing, they’ve got you covered.

      Strength That Speaks Volumes

      Nitronic 60 Key-locking Inserts don’t just resist wear; they embrace strength. High stress, high torque — bring it on! The formidable might of Nitronic 60 makes these Key-locking Inserts the backbone for applications that can’t afford to falter, from the aerospace zeniths to the depths of automotive innovation.

      The Nitronic 60 Difference

      We hear you asking, “But how do they stack up against other materials?” Here’s the deal:

      Nitronic 60, as a material, is a high-performance stainless steel alloy known for its excellent strength and resistance to wear and galling. This versatile alloy provides exceptional resistance to high temperature oxidation, crevice corrosion and general corrosion, making it well suited to marine and chemical applications. Key-locking inserts made from Nitronic 60 are used in various applications where high strength and corrosion resistance are a must.

      • Carbon Steel Inserts: Compared to standard steel, Nitronic 60 offers superior resistance to corrosion and galling.
      • Stainless Steel Inserts: Among stainless steels, Nitronic 60 typically outperforms varieties such as 304 or 316 in wear resistance.
      • Inconel Inserts: Inconel excels in high-temperature applications but comes at a higher cost and greater machining difficulty than Nitronic 60.
      • 4140 Alloy Inserts: 4140 Alloy provides greater tensile strength and enhanced performance at high temperatures, although it falls short in corrosion resistance and often necessitates protective coatings. Nitronic 60 is better suited for applications involving friction at moderate temperatures.
      • A286 Inserts: A286 excels in high-temperature applications, maintaining higher strength at elevated temperatures, though it’s tougher to machine and more expensive than Nitronic 60.

      A Spectrum of Possibilities

      We’re not about “one-size-fits-all” because we know your engineering needs are as unique as your blueprints. That’s why we offer Key-locking Inserts in inch, mil-spec and metric sizes that are tailored to the scope and scale of your vision — common internal diameters include #2-56 through 1 1/2-6 for inch & mil-spec sizes, and M2 through M24 for metric sizes. And with varying lengths at your disposal, the only limit is the application and your imagination. Materials

      Compliance with stringent industry standards is not just a promise; it’s our practice. Our inserts meet or exceed critical aerospace and military specifications, ensuring that they deliver in applications where there is no room for error. Standards available include MS51830, MS51831, MS51832, NAS1394 and NAS1395. Series available include Miniature KNC, Thin Wall KN & KNM, heavy-duty KNH & KNHM, and extra heavy-duty series KNHXH.

      Whether you’re in aerospace, automotive, defense, or any field that demands unyielding materials, these inserts are ready to serve. They’re the go-to for applications that require repeated assembly and disassembly, ensuring longevity and reliability every step of the way.

      Discover More, Achieve More

      MF Supply is a WBE/WOSB certified business, and a trusted supplier of Nitronic 60 Key-locking Inserts (AKA Keenserts®) for manufacturers, government and industry. Eager to delve deeper into the world of Nitronic 60 Key-locking Inserts? Visit our website, where innovation is just a click away, and join the ranks of manufacturers and engineers who don’t just build, but inspire.

      With Nitronic 60 Key-locking Inserts, it’s not just about holding things together; it’s about unlocking possibilities. Discover the sizes, standards, and the success that our inserts can enable.

      Inch & Mil-Spec Nitronic 60 Key-locking Inserts

      Metric Nitronic 60 Key-locking Inserts

      Do you still have questions or would like to speak with a representative? Reach out to us, and our MF Supply team of sourcing experts will help you find what you’re looking for. “Finding the right screw for you” is our tag line after all!

      Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

      MF Supply Work With Us

      Six Reasons To Buy From MF Supply

      • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
      • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
      • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
      • Creatively Solve Problems – We are sourcing experts and specialize in hard to find parts. We offer custom manufacturing and reworking solutions at competitive pricing, reducing long deliveries.
      • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
      • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

      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. 

      MF Supply Expands Online Product Catalog to 22,189 Unique Items and Counting!

      Posted: October 26, 2023 | Author: | Filed under: Bolts, DFARS, Fasteners, Holo-Krome, Mil-Spec, Plastite Alternative Screws, Socket Head Cap Screw, Supply chain - manufacturing, Taptite Alternative Screws, Threaded Fasteners, Trilobular Fasteners | Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

      Greetings to our precision manufacturing community!

      MF Supply is a leading WOSB / WBE Certified distributor of commercial, mil-spec and custom made fasteners. With a legacy of over half a century and a reputation for continuously evolving to meet our customers’ needs, we are thrilled to announce the recent expansion of our online catalog to include a whopping 22,189 unique items! Our updated catalog now includes Holo-Krome branded products, non-standard, domestic and DFAR Socket Cap Screws, an extensive list of Bolts, and more Thread Rolling & Thread Forming Screws.

      We are constantly evolving to meet the changing needs of manufacturers. With this strategic expansion, we underscore our commitment to as a comprehensive one-stop shop for commercial and mil-spec fasteners and hardware for industrial and precision manufacturers, ensuring our customers have a seamless and efficient purchasing experience online and offline.

      New Product Highlights:

      1. Socket Cap Screws:  We have always stocked and sourced a variety of imported, domestic and mil-spec socket cap screws. Our recent expansion in this category include standard and nonstandard sizes, and a variety of standard and exotic materials. We are now offering more Button Head, Flat Head, Flat Head 100 degree, Low Head and Standard Socket head cap screws in a wider choice of materials including: A286, Brass, Inconel, Silicon Bronze, and 316 Stainless Steel, in addition to regular Alloy and 18-8 Stainless Steel. 

      2. Bolts: Our selection of bolts has undergone a significant enhancement and now includes 18 Bolt categories, in multiple sizes and materials. Materials offered include Steel, B7 Alloy, Stainless Steel, 316 Stainless Steel, Aluminum, Silicon Bronze, A2, A4, Brass, Inconel and Nickel-Copper. Our 18 bolts’ categories include:

      3. Holo-Krome Products: We are proud to announce the inclusion of Holo-Krome brand fasteners to our catalog. Holo-Krome, a reputable domestic OEM, is well known for their extensive offering of quality products within the Socket Products segment. We introduce the following Holo-Krome products that are now available for purchase directly in our website: Dowel Pins, Hex Socket Shoulder Screws, Socket Cap Screws, Allenuts, Socket Jam Screws, Socket Pressure Plugs, and Socket Set Screws. 

      4. Thread Rolling / Thread Forming Screws: We also expanded our online offering to now include over 2.7K alternatives to Plastite® & Taptite® Screws. Our recent expansion in this category include more Steel, Black Oxide and Stainless Steel screws. Our off the shelf products are ready to ship from multiple warehouses across the USA, and include:

      By bolstering our product offering in these key areas, we aim to be the preferred supplier for manufacturers in various sectors, including: aerospace, OEMS of instrumentation, equipment and machines, architectural metal and glass, sheet metal fabrication, contract manufacturers, lighting, furniture, and elevators.

      Manufacturers working with us can expect timely deliveries, competitive pricing, and access to expert guidance to help optimize their fastener choices. Manufacturers eager to explore our product catalog, including our recently expanded product categories, are encouraged to visit our website at www.mfsupply.com, reach out to us at sales@mfsupply.com or request a quote. Our MF Supply team of sourcing experts will help find what you need. “Finding the right screw for you” is our tag line after all!

      “At MF Supply, we understand the dynamic needs of the manufacturing industry, including the balance of price, quality, availability and certification paperwork. The expansion of our product catalog demonstrates our commitment to being a one-stop solution for all fastener needs. Whether it’s standard fasteners, specialized custom hardware, mil-spec parts or OEM brand names like the trusted Holo-Krome brand, we have it all under one roof.” – Robin Lieberman, President of MF Supply.

      Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.

      MF Supply Work With Us

      Six Reasons To Buy From MF Supply

      • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
      • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
      • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
      • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
      • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
      • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

      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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