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

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. 


Precision Dowel Pins for Manufacturers: A Comprehensive Guide

Considering Precision Dowel Pins for Your Next Project?

When you’re in the heart of the manufacturing industry, precision is not just a luxury; it’s a necessity. Components like dowel pins may seem small and inconsequential, but in this realm of precision manufacturing, they are paramount to ensuring accurate alignment and fit. Precision dowel pins, in particular, play an indispensable role in guaranteeing accurate alignment and secure fastening in a broad spectrum of applications. But with various tolerances, standards, materials, and sizes available, how do you make the right choice? It is important to know and understand these factors in order to make informed decisions that will meet your expectations & manufacturing needs.

What are Precision Dowel Pins?

At their core, precision dowel pins are simple cylindrical rods. The term “precision” implies that these pins are manufactured to very tight tolerances in order to ensure accurate fit in assemblies. Tolerances refer to the acceptable variation in dimensions from the specified value. The tighter the tolerance, the less variation there is—meaning that their dimensions are incredibly accurate. This precision ensures that dowel pins fit snugly into corresponding holes in two components, ensuring their exact/accurate alignment.

Standards & Tolerances

Several standards are followed in the production of precision dowel pins. The prevalent standard specifications come from the International Organization for Standardization (ISO), the Deutsche Industrie Norm (DIN), the American National Standards Institute (ANSI), and the Military Standard (MS/MIL-SPEC) of the United States. At a minimum, these standards specify the pin shape, and the diameter and length tolerance. These standards might also specify the pin hardness and surface finish. OEM branded dowel pins are handled separately and are addressed later in this blog.

ISO Standard: ISO 2338A & ISO 2338B (for unhardened pins) and ISO 8734 (for hardened pins) are common standards for dowel pins. Under these standards, precision dowel pins can be manufactured to either “M6” or “M5” tolerance classes, with “M6” being the more common of the two.

  • For example, an “M6” tolerance for a 5 mm dowel pin might have a diameter tolerance of -0.014 to 0 mm. So, the pin could be anywhere from 4.986 mm to 5 mm in diameter.

DIN Standard: DIN 7 (for unhardened, solid dowel pins) and DIN 6325 & DIN 6325H (hardened, solid dowel pins). Similar to ISO standards, the typical tolerance for precision dowel pins under DIN standards is designated as “M6.” This is the standard fit for dowel pins and ensures a tight fit that might require light pressing or can sometimes be hand-driven depending on the exact material and hole conditions.

  • For example, for a 5 mm dowel pin under the DIN 7 or DIN 6325 standard, the typical diameter tolerance might have and upper limit of 5.000 mm & a lower limit of 4.986 mm.

ANSI Standard: ANSI standard for dowel pins is ASME/ANSI B18.8.2. This standard defines sizes and tolerances for standard dowel pins, with the “Standard Series” being the most common.

  • For example, for a 1/4 (.25) inch interference fit diameter pin, the diameter tolerance might be +0.0002 to 0.000 inch. So, the pin diameter could be anywhere from 0.2500 inches to 0.2502 inches in diameter.

MIL-SPEC Standard: MIL-SPEC standard for dowel pins, particularly those conforming to MS16555 and MIL-P-21143 have very specific tolerances to ensure reliability and consistency in critical military and aerospace applications.

  • The MS16555 specifies a straight headless pin with a radius on one end and a chamfer on the other. The material can be Carbon or Alloy Steel or CRES 410 or 416 Stainless Steel. Available diameters range from 1/16 (.0626-.0628) through 1 inch (1.0003-1.0001). Lengths range from 3/16 to 6 inches long. Standard diameter tolerances are +.0002 over the nominal size.
  • The M21143 specifies a a straight headless pin made of CRES 303 Stainless Steel. The Mil-P-21143/1 series has a tolerance up to +.0002 over the nominal size. The M21143/2 series has tolerance of .0002 Under its nominal size.

Material Choices

Different applications may require Precision dowel pins made from different materials. The most common materials in the market include:

  • Stainless Steel: Offers corrosion resistance and is suitable for applications exposed to moisture or corrosive substances.
  • Alloy Steel: Known for its strength and durability, it’s ideal for heavy-duty applications.
  • Brass: Often used when there’s a need to avoid sparking or in applications with lower strength requirements (less common).
  • Aluminum: Lightweight and resistant to corrosion, aluminum precision dowel pins are suitable for applications where weight is a concern (less common).

Sizes Available

The diameter of precision dowel pins usually varies from 1/32″ to more than 1″, and their lengths span from 3/16″ to multiple inches. Hence, precision dowel pins come in a wide range of sizes, but certain sizes are more commonly used across various manufacturing applications due to their adaptability and compatibility with standard components. Selecting the appropriate size for your specific application is essential for achieving a snug fit, best performance, cost-effectiveness, and durability.

OEM Branded Precision Dowel Pins

Precision Dowel Pins – OEM branded “Precision” dowel pins are manufactured by precision component brands such as Pic Design, WM Berg, Unicorp and others who have their own technical specifications and are not governed by DIN, ISO or ANSI / ASME standards. They are usually only offered in stainless steel through distributors of precision components.

What to Consider Before Buying

  • Tolerance: Precision dowel pins have tight tolerances. Ensure that the pins you buy meet the specific tolerances required for your application.
  • Environment: Consider the environment in which the pins will be used. If they’ll be exposed to corrosive substances or high temperatures, material choice becomes crucial.
  • Custom Needs: If your application requires non-standard sizes or materials, you might need custom-made precision dowel pins.
  • Quantity: Depending on the scale of your manufacturing, you may need precision dowel pins in bulk. Purchasing in larger quantities often results in cost savings!
  • Supplier Reputation: Always source your precision dowel pins from reputable suppliers known for their quality and consistency.

Precision Dowel Pins at MF Supply

MF Supply is a WBE/WOSB woman owned business, and a trusted supplier of Functional Equivalents, including precision dowel pins, to OEMs, manufacturers, industry, and government. We are precision dowel pin experts, offering the full catalog of dowel pins in Inch, Metric, Military and OEM branded options in a wide selection of materials, sizes and specifications. As stocking distributors, many precision dowel pins are available and ready to ship today from our national distribution centers.

Browse through the links provided below to find the precision dowel pins that you need:

  • Mil-Spec Precision Dowel Pins: The full range of commercial and MIL-SPEC parts (M21143, MS16555, MS9390), including parts that are USA made, DFARS and ROHS compliant.
  • Inch Precision Dowel Pins: inch sizes to ASME ANSI B18.8.2 standards in alloy steel, stainless steel 18-8, 316, 400 series and hardened. Domestic and Imported options are available.
  • Metric Precision Dowel Pins: Metric sizes including DIN 7, DIN 6325, and ISO 2338 and 8734 in alloy steel, A2 & A4 stainless steel
  • Precision Series and OEM branded equivalents to PIC, BERG, both Inch & Metric precision dowel pins including Press-Fit A, B and Slip-Fit C series and all MD series pins in 416 and 303 stainless steel.
  • Please send us a Request for Quote for any other dowel pins not listed.
  • Custom made parts per print.

Your next step?

If you have additional questions or need help in selecting the right precision dowel pins for your next project, don’t hesitate to reach out to us or send us a quote request. Our team of sourcing experts is always ready to assist you on your journey to manufacturing excellence. 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, 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. 


Cotter Pin!? What the heck is that?

Welcome back to the next installment of our “what the heck is that” series, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. This week, we are introducing you to our friend, the Cotter Pin!

Cotter Pins, AKA Split Pins, R Clips or R Pins, Hitch Pins or Hitch Clips, Safety Pins, Circle Cotters, Retaining Pins or Locking Pins, may not be the most renowned piece of hardware, yet they have been quietly holding together our world in more ways than you might imagine. For starters, these pins are non-threaded fasteners, which means that they do not have the risk of loosening due to vibrations as is the case in some screw or bolt connections. Furthermore, Cotter Pins are easy to install/remove and are inexpensive to produce—making them valuable & cost-effective components that guarantee the stability and functioning efficiency of numerous mechanisms across a variety of industries. Keep reading to learn more about these pins and to see if they would be a great fit for your next big project.

What are Cotter Pins?

Cotter Pins are double-structured pins crafted from semi-round wires, that have a loop on one end that serves as a head. The completed component showcases one wire end extending past the other, ending with a chisel-like point.

At the most basic, cotter pins are fasteners that are used to secure various assemblies in place. Typically, they are shaped like a “T” or an “R”, and are inserted into holes that run through the parts to be connected. They are then split into two prongs at the opposite ends, which are then bent to prevent the pins from slipping out and to securely hold the assemblies together.

One key advantage of cotter pins is their inherent simplicity. With their straightforward design, they can be easily installed and detached without the necessity for any specific tools. Furthermore, they offer robust links that prevent the secured pieces from becoming loose or disassembled. When used with castle or slotted nuts, they become a safety locking device.

Another important benefit offered by cotter pins is their ease of removal, which enables swift disassembly or maintenance tasks. When the need arises to dismantle/disassemble components, cotter pins can be easily taken out by straightening or bending back their split ends to their original position. This feature simplifies repair or maintenance operations.

Cotter pins also allow for a certain degree of motion (pivot) depending on how they are installed. This is beneficial in applications like bicycle crank arms where you want the crank to remain secure while also allowing it to rotate.

Who uses Cotter Pins?

Cotter Pins are widely used across a range of industries due to their simplicity, reliability, and versatility. The following are some primary industries where cotter pins are frequently employed:

  • Aerospace Industry: Cotter Pins play a vital role in the aerospace industry, where safety and reliability are paramount. They are used to secure critical components such as landing gear, engine parts, and control linkages, ensuring that they remain in position during flight. For example, control linkages encompass control surfaces such as ailerons, elevators, and rudder, as well as the cockpit controls, all of which have numerous pivot points requiring both security and mobility. Cotter Pins are perfectly suited for these uses.
  • Automotive Industry: In the automotive industry, cotter pins are utilized in various components, particularly in suspension systems, steering linkages, transmission linkages, wheel assembly, brake system, etc. They secure ball joints, tie rod ends, and other critical parts to ensure safe and reliable vehicle operation.
  • Agriculture Industry: In the agricultural sector, cotter pins serve the purpose of fastening elements in various farming machinery, including plows, harrows, and cultivators. Cotter pins also find use in several components of tractors, including anchoring the joint connections in the steering mechanism, maintaining components in the transmission system, and fastening parts in the hydraulic systems.
  • Marine Industry: Within the marine industry, Cotter Pins are widely employed to secure clevis pins, turnbuckles, and various fittings in rigging systems and boat hardware. For instance, within marine engines, cotter pins are often used to secure various components and assemblies, such as linkages, connections, and valves. Offering a swift and secure fastening solution, these pins demonstrate reliability even in corrosive marine environments.
  • Military and Defense: In the military and defense industries, cotter pins are used to fasten components in weapons, vehicles, aircrafts, naval assets, and communication equipment. In addition, Cotter Pins are deployed in a wide array of other portable gear and systems utilized by military personnel in operational settings. These can encompass everything from temporary bridges and fortification structures.

Other industries that make use of Cotter Pins are: the Industrial and Machinery Industry, where Cotter Pins are used for securing components, such as pulleys, gears, and levers; the Mechanical and Electrical Engineering Industry, where they are used to to fasten parts, such as bolts, nuts, and shafts; the Recreational and Sports Equipment Industry, where they secure various moving parts and components found in recreational equipment, such as bicycles, motorcycles, and sports gear; the Construction and Heavy Equipment Industry, where these pins are used for various applications, including securing hitch pins, linkages, and hydraulic connections; and the Furniture and Manufacturing Industry, where these pins are utilized to secure joints, hinges, and other components in conveyor systems, furniture assembly, and .

What standards, materials and sizes are available?

Materials: Cotter pins can be manufactured from different materials like steel, stainless steel, brass, and aluminum. Steel cotter pins are often enhanced with a zinc coating for added resistance to corrosion. Stainless steel pins are favored for their superior strength and corrosion resistance, particularly in harsh environments.

Sizes: Cotter pins come in a spectrum of sizes, generally ranging from 1/32″ to 3/4″ in diameter and 1/2″ to 6″ in length. The appropriate size is dictated by the application and the dimensions of the hole where the pin will be placed.

Standards: Various nations and regions adopt their own standards for cotter pins. Some of the most frequently used ones include the American Society of Mechanical Engineers (ASME), American National Standards Institute (ANSI), British Standards (BS), Military Specification (Mil-Spec) Standard, and the Deutsches Institut für Normung (DIN).

Commercial Standards include: ASME B18.8.1

Mil-Spec standards include: MS9245

Are there other factors to consider?

YES!! The efficacy of cotter pins are greatly influenced by their proper installation and maintenance. The following list has crucial points to keep in mind.

  • Selection: Opt for cotter pins that fit into the hole securely without being overly tight. The length should be sufficient for the prongs to be bent appropriately without leaving excessive overhang.
  • Installation: During installation, ensure the prongs are split and bent sufficiently to secure the pins. Tools like pliers or a cotter pin puller can aid in the process of installation and removal.
  • Inspection: Regular checks on cotter pins are crucial, particularly in applications under high-stress or where safety is paramount. Look out for signs of wear, corrosion, or distortion, indicating potential need for replacement.
  • Replacement: When extracting cotter pins, it’s typically advised to substitute them with new ones, as the bending and straightening process can fatigue the metal, undermining their strength.

Cotter Pins at MF Supply

We currently offer:

  • A full range of commercial parts, including parts that are ROHS compliant.
  • Inch Cotter Pins are now available for online purchase at our website! Stock sizes include 1/16 through 1/2 in Steel with a Chisel Point and Zinc Plating, as per standard ASME B18.8.1 specifications.
  • Mil-spec Cotter Pins MS9245 are also available for online purchase. Stock sizes include 1/32 through 5/32 in T321 Stainless Steel , with Manufacturers Certifications.
  • Please send a Request for Quote for any other Cotter Pin not listed on our website.
  • Brand names and generic equivalents.
  • Custom made parts per print.

For more detailed information on Cotter Pins or other products, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can 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

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. 


Precision Shoulder Screws!? What the heck are those?

What the heck are Precision Shoulder Screws?

Here we go again, with our “what the heck is that” series refreshed for 2023, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. Today, we will re-introduce you to the Shoulder Screw!

What is a Precision Shoulder Screw? 

Shoulder Screws, which are sometimes called Shoulder Bolts or Stripper Bolts, are (generally) hex socket screws with an enlarged, unthreaded cylindrical shoulder under the head.  They are comprised of 3 main parts: the head, the shoulder and the thread.  They come in two basic categories, “Commercial” and “Precision”.

Commercial Shoulder Screws are made to inch standard ANSI ASME B18.8.2.  The size range for the shoulder diameter is from ¼ to 2”.  The thread class is 3A and the tolerance on the shoulder is +.005 /  -.005.

Precision Shoulder screws are sometimes referred to as “tight tolerance” shoulder screws. They are not governed by any official ANSI or ASME standard. The size range for the shoulder diameter is from 3/32 to ½.  The thread class is 2A and the tolerance on the shoulder diameter varies from +.000/-.001 to  -.0005 to -.0015 depending upon the manufacturer. Now that’s precise!

Who uses Shoulder Screws?

Just as Dowel Pins and Retaining Rings are used to locate or hold parts together within a precision assembly or a fixture, so are Precision Shoulder Screws.

Yet shoulder screws are more versatile. When installed, the unthreaded shoulder acts as a shaft for rotating items such as bearings and bushings, precision spacing, machinery support, and motion guiding. Precision Shoulder screws exacting tolerances make them ideal for use with other precision components.

They are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more.

What do I need to consider when selecting Shoulder Screws?

Although Shoulder Screws are offered in a multitude of materials and styles, when it comes to the main commercial and precision offerings, there are a few main issues to consider.

Which Drive and Head Style?

Precision shoulder screws are readily available in hex socket and slotted drives.  Philips drives are available in certain sizes. Torx and Star are available for special order. Typical head styles are a modified fillister with a flat top where the head diameter is about twice the head height. Low head fillisters are available in certain sizes

Which material do I need?

Precision shoulder bolts are readily available in Type 18-8/303 Stainless Steel and 416 Stainless Steel.  316 Stainless Steel, Alloy and other exotic materials are available for special order.

Are there other factors to consider?

When ordering Precision Shoulder screws, specify the Shoulder Diameter, Shoulder length, thread size, material and drive type. For example, an example of a typical Precision Shoulder screw is a ¼ shoulder x ½ long x 10-32 thread in SS18-8 with a hex-socket drive. Non-locking is the most popular style, but locking may also be available.

Precision Shoulder Bolts  often show up under their brand name.  Some of the most popular brands include: BERG, Concord, Globe, PIC, Lyn-tron and RAF. A comprehensive selection of Shoulder Screws is also offered by McMaster-Carr (tight tolerance series), MSC and Grainger.

Finally, Precision Shoulder Screws can also show up under their Mil-spec numbers, which include MS51575 & MS51576 and are DFARS compliant with full paperwork.

Precision Shoulder Screws at MF Supply

We currently offer:

  • The full range of commercial and mil-spec parts, including parts that are DFARS and ROHS compliant.
  • MS51576 Now available for online purchase!
  • Brand names and generic equivalents.
  • Custom made parts per print in non-standard and exotic materials and finishes.
  • Inch, Metric and Mil-Spec sizes.

For more detailed information on Precision Shoulder Screws, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can 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

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. 


Mil-Spec DFARS!? What the heck is that?

Welcome to the second edition of our “What the heck is that” series, refreshed for 2023, where we discuss some of the unique fasteners and electronic hardware that 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. For example, the MS24693C pictured above is a fastener produced according to strict military standards that are maintained by the DLA (Defense Logistics Agency). (https://www.dla.mil/) INSERT THIS LINK I DONT KNOW HOW

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 Mil-spec fasteners.  These suppliers have met all the government’s requirements and pass the highest quality control standards. This designation is called Qualified Suppliers List for Manufacturer’s [QSLM].

AKA – Also known as…..

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.  An example of one of the most common and popular Mil-spec machine screws is the MS24693C.  Its commercial equivalent is a Phillips Flat 100 degree Machine Screw in 300 series stainless steel.  Below, we’ll tell you more about this popular fellow.

Who uses Mil-spec Fasteners?

Mil-spec fasteners may be 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, naval vessels and weapons systems.

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.

Qualifying countries include: 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.

Important Note:  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.

Visit the DPC website, section 252.225, to keep up to date with DFARs requirements, which were updated January 2023. Click here: https://www.acq.osd.mil/dpap/dars/dfars/html/current/252225.htm.

An example of a DFARS Mil-Spec Screw please!

As we’ve learned, the MS24693C is actually Phillips Flat 100 degree Machine screws in 300 series stainless steel.   The MS24693-C4 is a 4-40 x 3/8 Phillips Flat 100 Degree Machine Screw in 302 Stainless Steel, and it is one of the most widely used sizes.  Interestingly, the MS24693C superseded the AN662C series, so you might come across the AN662C on an older print of bill of materials.  Keep in mind, with any design or manufacturing decision, the reason for using a specific screw generally rests in the hands of engineering.

Features of the MS24693C

  • Strict military standards ensure performance and reliability
  • Made/melted in the USA or other DFARs-approved country
  • Materials and dimensions meet Federal standard FF-S-92
  • Inspected per Mil-I-45208
  • Full lot traceability, manufacturer’s certification and chemical and physical certification
  • Available in diameters from #0 through 1/4 inch in coarse and fine thread and various lengths

Lessons Learned

Considerations when purchasing MS24693C or other Mil-spec DFARs fasteners.

  1. 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 directly from the manufacturer.
  2. When purchasing Specialty metal screws that qualify for DFARS, 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!

MS24693C and other Mil-spec DFARS Fasteners in Stock!

Here, at MF Supply, we stock some of the most common Mil-spec Fasteners, including the following: Machine Screws, Socket Screws, Hex Head Cap screws, Nuts, Flat washers and Standoffs and Spacers. Checkout our instock Military Line of fasteners. (LINK HERE https://www.mfsupply.com/mil-spec-fasteners-s/1823.htm) . If you don’t what you need listed, send us an RFQ, as we are sourcing experts!

Visit our website for more detailed information on Mil-spec Fasteners. Also, checkout our military linecard!

And, as always, if you don’t see it listed, ask us.  “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, 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. 


Buyer’s Guide to Metric Dowel Pins Refreshed for 2023!

7 Things to Know When Buying Metric Dowel Pins

This guide is a follow up to our Dowel Pin Buyer’s Guide published last week, on February 23, 2023.  This post is specifically written to share with you the available options when it comes to procuring precision Metric dowel pins.

Our goal is to help simplify the buying process and guide you in the critical selection factors for this sometimes complex and confusing category of fasteners.

1. What standards are Metric Dowel Pins made to? 

Metric dowel pins are tricky because they fall into two buckets:

  1. DIN / ISO standard – These metric Dowel pins are readily available in the commercial marketplace and in addition to your suppliers, can be procured through national catalogers like Mcmaster-Carr, Grainger and Holo-Krome. They come on steel and stainless steel.
  2. Precision Metric Dowel Pins – These “Precision” dowel pins are manufactured by precision component brands such as Pic Design, WM Berg and Unicorp who have their own technical specifications and are not governed by DIN or ISO standards. They are usually only offered in stainless steel through distributors of precision components.

2 . What are the specific criteria I can select for Metric dowel pins?

Here is a list of the criteria and available options available:

  • Size
  • Material
  • Hardened or Unhardened
  • End style
  • Tolerances

3 . Can you list the standard and precision dowel pins available off the shelf?

4. Which types of metric dowel pins are available in which sizes and materials? 

Use this handy grid to understand the sizes and materials available in each Metric dowel pin style.

Standard
Ends
Materials
Tolerances / Fit
Hardness
Diameters
DIN7
ISO 2338
ISO 2338A
Rounded or beveled 
Steel (least common)
 
300 Series Stainless Steel including
A1=18-8, 303, 304
A4=316
M6 diameter tolerance
Slightly Oversized
 
aka Press Fit
Unhardened
M.8-M20
ISO 2338B
Rounded or beveled
300 Series Stainless Steel
A1=18-8, 303, 304
H8 diameter tolerance
Unhardened
M1.5-10
DIN 6325
DIN 6325H
ISO 8734A
ISO 8734
 
Rounded on one end
Beveled on one end
Alloy Steel
M6 diameter tolerance
Slightly Oversized
 
aka Press Fit
Hardened to
RHC 52-62
M1-M25
Precision Unhardened
Rounded
300 Series Stainless Steel
M6 diameter tolerance
Slightly Oversized
 
aka Press Fit
Unhardened
M1-M12
Precision Hardened
Rounded on one end
Beveled on one end
416 Stainless Steel
M6 diameter tolerance
Slightly Oversized
 
aka Press Fit
Hardened to
RHC 36-42
M2-M10

Important note:  All pin options may not be available in all sizes and materials.

5. When ordering, do I need to specify the dowel pin tolerance or call out attributes such as standard, undersized or oversized fit? 

Metric dowel pins can show up under DINs and ISO numbers, including : DIN 7, DIN 6325, and ISO 2338 and 8734. When ordering DIN/ISO dowel pins it is best to include the Diameter, Length, Material, DIN or ISO and tolerance.  For non DIN/ISO Precision metric dowel pins, you can order by the manufacturer part number, such as Pic (MDP series), WM Berg (DM Series), or Holo-Krome.

6. Can I specify if I need radius (round) or chamfer (bevel) on the pin ends?

The pin style will depend upon the spec and the material. Precision dowel pins may come with either a double chamfer, double radius, or a radius on one end and a chamfer on the other end.  Check with the handy grid above for guidance.

Important note:  The configuration of the ends of unhardened metric dowel pins are at the discretion of the manufacturer.  If you have a specific style requirements, you might need to special order which usually involves a minimum and a lead time.

7. What if I need domestic or DFAR certified Metric dowel pins? 

If you are ordering by a Precision Manufacturer part number, you are in luck!  Most of the stainless steel pins produced by Pic, WM Berg and Unicorp qualify as DFAR compliant and full certifications with material certs and test reports are often available for USA made parts for a fee.

Metric Dowel Pins at MF Supply

We offer:

  • The full range of commercial Metric Dowel pins including parts that are USA made, DFARS and ROHS compliant.
  • Metric sizes including ASME ANSI B18.8.2, DIN 7, DIN 6325, and ISO 2338 and 8734
  • Metric Precision Dowel pins including Press-Fit Series and all MD series pins in 416 and 303 Stainless Steel.
  • Brand names and generic equivalents.
  • Custom-made parts per print in non-standard sizes and exotic materials and finishes.
For more detailed information about Metric Dowel Pins, to request a line card, or to send an RFQ, visit our website. And if you don’t see what you need listed, as always, ask us. “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, 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. 


The Buyer’s Guide to Dowel Pins You Must Have Today!  Updated for 2023!

MF Supply is a trusted Supplier of Precision Dowel Pins for manufacturers. Through our extensive assortment of Inch, Metric, Commercial, Mil-Spec and OEM brand names and equivalents, we offer our customers quality imported and domestic dowel options. Our products are competitively priced with fast delivery from multiple distributions centers across the USA. Our goal is to help simplify the buying process for this sometimes complex and confusing category of fasteners.

8 Things to Know When Buying Dowel Pins

If you are a manufacturer working with complex assemblies or fixtures, then you’re likely very familiar with precision dowel pins. Commonly used as a hinge, shaft or pivot to locate or hold assembled parts together, dowel pins can withstand frequent insertion and removal without distortion. They are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more.

Our goal is to help simplify the buying process for this sometimes complex and confusing category of fasteners.

1. What is a precision dowel pin? 

Dowel pins are solid, headless cylindrical shaped straight metal pins with a centerless ground finish. Manufactured to precise fractional diameters and lengths, dowel pins come in a variety of sizes, styles, designs and materials. This variability can cause confusion among buyers, engineers and end-users alike.

2. What materials and platings are available?

Precision dowel pins are available off the shelf in alloy steel (typically hardened) and stainless steel grades 18-8/303, 316 and 416 (typically hardened). Other exotic materials or special finishes are available for special order with a lead time.

3. What sizes are available?

Standard sizes include inch from 1/16″ to 1″ diameter, and metric from M1 to M20 diameter. Length options vary by diameter. Other diameters and special lengths are available for special order and usually involve a lead time.

4. When ordering, do I need to specify the dowel pin tolerance or call out attributes such as standard, undersized or oversized fit? 

Precision dowel pins often show up under their MIL-SPEC numbers, MS16555, MS16556 and Mil-P-21143. Metric dowel pins might show up under the following DINs and ISO numbers: DIN 7, DIN 6325, and ISO 2338 and 8734. Dowel pins might also show up under a manufacturer part number such as Pic, WM Berg, Unbrako or Holo-Krome.

If you are ordering by MIL-SPEC, manufacturer’s part number or DIN, then the general attributes including tolerance and style are known. Here are a few of the other options that will help you order the correct pin:

  • The most common standard inch or imperial sized precision dowel pin is made to the ASME ANSI B18.8.2 spec and has a diameter tolerance of -0.00 / +0.0002 and length tolerance of +/-0.010. For example, a ¼” (0.25) diameter standard dowel pin will have a diameter between 0.2500–0.2502″.
  • The standard metric tolerance is related to the DIN. Both DIN 7 and DIN 6325 have a standard m6 diameter tolerance of +0.012mm / +0.004mm and a length tolerance related to the specific pin length.
  • Undersized series dowel pins are used for inconsistent holes. They have a basic diameter 0.0002″ under the nominal diameter. For example, a ¼” (0.25) diameter undersized dowel pin will have a diameter between 0.2500–0.2498″. The Mil-P-21143/2- falls into the undersized category.
  • Important note:  All pin options may not be available in all sizes and materials.
  • OEM branded pins have their own tolerances and specifications.
  • Finally, the Oversized series of dowel pins are usually used to fit into worn holes and are generally used in the aftermarket for repairs. These pins are only available off the shelf in steel in a small range of sizes.

5. Can I specify if I need radius or chamfer on the pin ends?

The pin style will depend upon the spec and the material. Precision dowel pins may come with either a double chamfer or a radius on one end and a chamfer on the other end. Specific style requirements are available for special order and usually involve a lead time.

6. What information do I need to request a quote?

The easiest way to order is by either the manufacturer or MIL-SPEC part number. To order by description, you need the diameter, length and material and if applicable, and any special tolerance, plating or style requirements.

7. Do I need to buy special installation tools?

Just remember, no hammers! When installing dowel pins, never drive the pin into the hole with force. Always press it in for best results. And production favors pins since they require no extra fastening hardware for insertion, no secondary operations, and no mating parts. This ease-of-use adds up to speedier production, which makes everyone in the food chain happy!

8. What level of certification is required?

Generally, a Certificate of Conformance or a COC is sufficient for your customer. Full certification with material certs and test reports are often available for USA made and MIL-SPEC parts and might have an additional fee.

Available Dowel Pins Categories

We are Dowel Pin experts, offering the full catalog of standard Dowel Pins in Inch, Metric, Military and OEM branded options in a wide selection of materials, sizes and specifications. As stocking distributors, many dowel pins are available and ready to ship today from our national distribution centers.

  • The full range of commercial and MIL-SPEC parts (M21143, MS16555, MS9390), including parts that are USA made, DFARS and ROHS compliant.
  • Inch sizes to ASME ANSI B18.8.2 standards in Alloy Steel, Stainless Steel 18-8, 316, 400 Series and Hardened
  • Metric sizes including DIN 7, DIN 6325, and ISO 2338 and 8734 in Alloy Steel, A2 & A4 Stainless Steel
  • Precision Series and OEM branded equivalents to PIC, BERG, both Inch & Metric Precision Dowel pins including Press-Fit A, B and Slip-Fit C series and all MD series pins in 416 and 303 Stainless Steel.

In addition to our vast selections of standards, we offer Custom-made parts per print in non-standard sizes and exotic materials and finishes made here in the USA with full certifications. Minimums and lead times will apply.

Seeking parts not listed for purchase on our website? We’ve got you covered! Submit your Dowel Pin RFQ and our team of experts will return your quote quickly!


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. 

Read More conta.cc/3wxQF8E


Get the Job Done with a Pneumatic Power Tool

Now introducing the Rock Solid Hydro-Pneumatic Key-locking Insert Installation Tool

A single button is all it takes to operate this tool and to get the job done. No need to use a hammer and a drill to drive the key locking insert into place. 

Don’t know what a pneumatic power tool is or how to use one? Read on!

What is a pneumatic power tool? 

Pneumatic tools are designed to speed up the installation process of key locking inserts—also known as keenserts. They provide you with increased precision and control, improved torqueing, reduced vibration and noise, and more versatility for your projects.  

How do I use a pneumatic power tool? 

Using a pneumatic power tool is very simple and bound to give you some peace of mind in the process! To use a pneumatic power tool, simply set up or prepare the material to be used in the key locking insert (Keensert) installation process and: 

  1. Drill and countersink the material. 
  1. Tap the hole in the material. 
  1. Insert the key locking insert (Keensert) into the hole. 
  1. Screw the key locking insert down into the material with the aid of the pneumatic power tool!  

Keensert Installation Tool Kit

We offer the pneumatic power tool you need to quickly assemble your key locking inserts. Check them out here. Request a quote today, and our team of experts can help source your needs! 

Do you need more details on why you need a pneumatic power tool? Watch the video below!  

Optionally, you might also be interested on reading our previous blog posts about pneumatic power tools, and on how to manually install key locking inserts (Keenserts)


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

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. 


The Buyer’s Guide to Dowel Pins You Must Have Today!

MF Supply is a trusted Supplier of Precision Dowel Pins to manufacturers with our extensive assortment of Inch, Metric, Commercial, Mil-Spec and OEM brand names and equivalents.

Read More conta.cc/3wxQF8E


What the heck is Mil-spec DFARS? 2019

phillipsflat100degreemachine-new

MS24693C

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

www.acq.osd.mil/dpap/dars/dfars/html/current/225_0.htm

What is a Specialty Metal?

Title 48 – Federal Acquisition Regulations System, 252.225-7014 Preference for domestic specialty metals.

SPECIALTY METAL DEFINITION

(1) STEEL

(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.

http://www.gpo.gov/fdsys/pkg/CFR-1996-title48-vol3/xml/CFR-1996-title48-vol3-sec252-225-7014.xml

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
  • Titanium

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!