What the heck is Mil-spec DFARS? 2019Posted: July 29, 2019
Welcome to our ongoing “What the heck is that” series, where we discuss some of the unique fasteners and electronic hardware that precision manufacturers use in the design and assembly of their products. If you sell to the military either directly or indirectly, then you are probably aware of today’s topic: “DFARS” and “Mil-spec fasteners”.
What does Mil-spec mean anyway?
Before we get into the nitty gritty of DFARS, let’s discuss what makes a “Mil-spec” fastener. Mil-spec is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment. 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. For example, the MS24693C pictured above is a fastener produced according to military standards.
Mil-spec fasteners look a lot like their civilian cousins, but, these little guys are made to a specific standard that defines in detail, the screw’s attributes, including: dimensions, tensile strength, hardness, threads, drive type, material qualities and plating, just to name a few. Mil-spec fasteners are even traceable by lot to designated manufacturers. The government maintains a list of factories and suppliers who are qualified to manufacture and distribute Mil-spec fasteners. These suppliers have met all the government’s requirements and pass the highest quality control standards. This designation is called the Qualified Suppliers List for Manufacturer’s [QSLM].
Who uses Mil-spec Fasteners?
Mil-spec fasteners are used by anyone manufacturing or servicing military equipment. Often, the bill of materials calls for specific Mil-spec grade fasteners in accordance with a part number, drawing or procurement requirement. Some of the most common uses of Mil-spec fasteners include aerospace and naval vessels.
Now, tell me 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.
The Defense Federal Acquisition Regulation Supplement declares the following:
- Provides specific acquisition regulations that must be followed in the procurement process for goods and services for the Department of Defense and its contactors.
- FAR 252.225-7014 specifies “A Preference for Domestic Specialty Metals” in the manufacturing of fasteners. Berry Act, Buy American.
- The Specialty metals must be melted and manufactured in the United States or a “Qualifying country.”
What is a Qualifying Country?
Qualifying country” means a country with a reciprocal defense procurement memorandum of understanding or international agreement with the United States in which both countries agree to remove barriers to purchases of supplies produced in the other country or services performed by sources of the other country, and the memorandum or agreement complies, where applicable, with the requirements of section 36 of the Arms Export Control Act (22 U.S.C. 2776) and with 10 U.S.C. 2457.
Qualifying countries include the following 27: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Egypt, Estonia, Finland, France, Germany, Greece, Israel, Italy, Japan, Latvia, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom of Great Britain and Northern Ireland.
To keep up to date with DFARs requirements, visit
What is a Specialty Metal?
Title 48 – Federal Acquisition Regulations System, 252.225-7014 Preference for domestic specialty metals.
SPECIALTY METAL DEFINITION
(I) WHERE THE MAXIMUM ALLOY CONTENT EXCEEDS ONE OR MORE OF THE FOLLOWING LIMITS: MANGANESE, 1.65 PERCENT; SILICON, 0.60 PERCENT; OR COPPER, 0.60 PERCENT; OR
(II) WHICH CONTAINS MORE THAN 0.25 PERCENT OF ANY OF THE FOLLOWING ELEMENTS: ALUMINUM, CHROMIUM, COBALT, COLUMBIUM, MOLYBDENUM, NICKEL, TITANIUM, TUNGSTEN, OR VANADIUM;
(2) METAL ALLOYS CONSISTING OF NICKEL, IRON-NICKEL, AND COBALT BASE ALLOYS CONTAINING A TOTAL OF OTHER ALLOYING METALS (EXCEPT IRON) IN EXCESS OF TEN PERCENT;
(3) TITANIUM AND TITANIUM ALLOYS; OR
(4) ZIRCONIUM AND ZIRCONIUM BASE ALLOYS.
Specialty Metals Include:
- Stainless steel
- High alloy steel like Grade-BD
- Cobalt Chrome Alloys or Grade 5 Chromium steel with high chromium content
- Nickel Alloys
Aluminum, Carbon Steel & Copper Alloys are not specialty metals and cannot be DFARS.
What is the difference between Domestic & DFARS?
This is a great question! There are 3 main factors used to determine the country where a fastener is made and how they are classified. 1) The origin of the metal 2) the country of melt and 3) the country of manufacture.
DFARs only related to specialty metals, and the country of melt & manufacture. Check with your customer before making any assumptions about what “domestic” means to them. 100% Domestic (metal origin, melt & manufacture) is becoming harder and harder to find. Many products are not available off the shelf and are “made to order” if DFARS or domestic is needed. This will involve a lead time and may have a minimum lot charge.
Lessons Learned: Considerations when purchasing MS24693C or other Mil-spec DFARs fasteners
- Always ask for “full certifications”. This includes part name, part description, date of manufacture, lot number, chemical composition of material, and treatment of material including plating or passivation.
- At point of purchase, make sure the screws are DFARS. If you do not specifically ask for DFARS-compliant screws, you might receive screws that don’t meet the DFARS requirements, in which case, they won’t meet military standards. We’ve learned this the hard way so hopefully you don’t have to!