“Heli-coils®” vs. “Keenserts®”: 3 differences you must know-Part 2 of 2

Welcome back to the second part of, “Heli-coils®” vs. “Keenserts®”: 3 differences you must know. As a refresher, both Helical Wire Inserts (AKA Heli-coils®) & Key-locking Inserts (AKA Keenserts®) are popular threaded inserts that are commonly used in precision manufacturing, transportation, and aerospace applications. Their uses overlap range from restoring/repairing stripped threaded holes, strengthening threaded holes in metals and other soft materials, providing high resistance to torque-out and pull-out, & to place threaded holes on materials too thin to accept them. The three main differences between Wire Inserts and Key-Locking Inserts lie in their strength, ease of installation & price. Today we will continue on from where we left of on our previous blog, and discuss about OEM brands, Mil-spec options, and how to order them!

Threaded Inserts’ Brands & Equivalents

A Helical Wire Insert, commonly known as “threaded wire insert,” is essentially a coil-wire made of stainless steel or other materials which, when installed, provide a new threaded hole surface. One of the most recognized brands for helical inserts is “Heli-Coil®,” but there are several others as well, including E-Z Lok, Bollhoff, Recoil, KATO, Perma-Coil, V-Coil and Time-Sert. Below is a list of some of the most well known brands for this category:

  • Heli-Coil®: Part of the Stanley Engineered Fastening brand, Heli-coil’s name is nearly synonymous with threaded wire inserts, and Heli-coil®is a registered trademark of Emhart® Teknologies, Inc.
  • Recoil®: Part of Howmet’s (previously Arconic, formerly Alcoa Fastening Systems) wire thread insert offering. Recoil offers helical wire inserts in bulk, replacement packets, kits and associated tools, taps and drill bits.
  • E-Z Lok®: Offering Wire Inserts under the E-Z Coil™ Helical Coil Insert brand, specializing in industrial and automotive .
  • KATO®: The Original Inventor & Manufacturer of the Bi-Directional Tangless Insert.

A Key-locking Threaded Insert, commonly known by the popular brand name “Keensert® and Keysert®,” is a solid bushing style threaded insert with unique external keys that get hammered into grooves through the threads—permanently locking the insert in place. Key-locking inserts are specifically designed for high-stress applications where strong, permanent threads are essential. Key-locking inserts offer exceptional resistance to vibration, torque-out and pull-out, making them suitable for critical components and assemblies that require a secure, immovable joint, or in scenarios where frequent assembly and disassembly might weaken the primary thread strength of the base material. While “Keensert®” is a trademarked name, tens of manufacturers and brands offer similar products in the solid threaded insert category including Acme, Camloc, Chrislynn, Clarendon, Fairchild, Loksert, Kaynar, Microdot and Tridair brands. Here is a list of the most popular brands:

  • Keensert®: is a registered trademark of Huck Patents, Inc. The trademark name is currently owned by the company that started it all, Howmet (formerly Arconic & Alcoa Fastening Systems).
  • Recoil®: The trademarked Keysert name belongs to Recoil, which is also part of the current Howmet family (formerly Arconic & Alcoa Fastening Systems).
  • Carr-Lane: Specializing in Tooling Components, Carr-Lane offers a large selection of Inch and Metric Key-locking inserts in steel and stainless steel.
  • Fairchild Fasteners®: Purchased by Arconic in 2002, Many original Fairchild part numbers are still produced and commonly used in the aerospace industry.
  • Acme – USA based manufacturers of inch, metric, Industrial Style and Mil-Spec key-locking inserts in a variety of materials and finishes.

Note: Various manufacturers and brands have their own designs, strengths, materials and applications for which they’re best suited. When choosing a threaded insert, it’s essential to consider factors like the material you’re working with, the stresses the insert will be under, and the expected lifecycle of the product. Industrial, automotive and aerospace industries each have their own requirements, which may include DFAR, First Article or other certifications. If you need assistance finding out what type of threaded insert is best suited for the project you’re working on, read part one of this blog, or reach out to us with your questions. MF Supply is an expert and leading supplier of Helical Wire Inserts and Key-locking Threaded Inserts—functional equivalents to top & expensive brands, such as Heli-Coil® & Keensert®.

Mil-Spec Options

Mil-spec Helical Wire Inserts (Heli-Coils®) are crafted to meet military specifications. They carry specific labels signifying their adherence to the rigorous standards established by the U.S. Department of Defense in order to guarantee that the inserts will fulfill the necessary requirements for military applications.

With that having been said, these threaded inserts often show up as free-running or self-locking inserts under their Mil-spec numbers, which can be crossed to commercial equivalents. Some common Mil-spec Helical Wire Inserts’ series include MS122076 through MS124831, MA1565, MA3276, MA3277, MA3278, MA3279, MA3280, MA3281, MA3329, MA3330, MA3331, , MS21208, MS21209, MS33537, NA0276, NAS1130

Mil-Spec key-locking threaded inserts (Keenserts®) adhere to distinct mil-spec (military specification) series. Options for these inserts include Miniature, Thinwall & Lightweight, Heavy Duty, Extra Heavy Duty, Keylocking Inserts in Stainless Steel, A286, and 4140 Alloy materials. Here are several prevalent mil-spec series associated with them: MS51830, MS51831, MS51832, NAS1394, NAS1395, NA0146, NA0147, NA0148, NA0149, NA0150, NA0151. The mil-spec parts will often have a commercial equivalent that is also known under the original Fairchild nomenclature, including the KN, KNC, KNH, KNL & KNCL Series.

Authentic Mil-spec parts will be available with documentation that confirm their compliance to the specification. Examples of certified paperwork might include a Certificate of Conformance, material traceability, DFAR statement, and chemical and/or physical tests reports.

How to Order

Now you know the differences between Helical / Heli-coils® and Key-locking / Keensert® / Keyserts®, the brands available, and the mil-spec series options.

To find the exact insert you are seeking on our website, there are currently four ways to proceed:

1. You can visit the Keenserts®, Threaded Inserts & Helical Wire Inserts category section of our website, and choose between Keenserts® for Manufacturers or Helical Wire Inserts. Once you select the desired category of products, you can then narrow down your search by selecting between metric or inch & mil-spec sizes, materials, etc.

2. You can also visit our website and enter the product standard, product number or keyword (e.g., MS51830, MS51830-101, “Keenserts,” “Helical Inserts,” etc.) in our search bar, and click the “Search” button. Once the list of available products are listed, you may use our product filters to search for the desired size, material, etc.

3. Alternatively, you could also use our newly added Product Finder tool! Select the desired Item Type, Subtype, Material, etc. And when you’re done selecting, simply click on the “Search” button, and the product finder will display a list of available products for you. 

4. Lastly, you could also reach out to us or Request a Quote. Our MF Supply team of sourcing experts are here to assist you and help you find the right product(s).

Once you find the insert you need, you can request a quote or buy online.

Key-locking Inserts (Keenserts®) & Helical Wire Inserts (Heli-Coils®) at MF Supply

MF Supply is a WBE/WOSB woman owned business, and leading supplier of Keenserts® & Helical Wire Inserts including major OEM brands and brand equivalents, in imperial, metric and mil-spec sizes and materials.

We stock a huge inventory including Miniature, Thinwall, Lightweight, Heavy Duty, Extra Heavy Duty, Locking, Non-Locking, Solid and Floating style Keenserts® in a variety of sizes and materials. Our mil-spec and certified insert products are DFAR compliant with COC and full certifications available upon request.

We Invite You To Request a QuoteDownload a Guide or a Line Card Today!

Do you still have questions or would like to speak with a representative to request a quote? 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, 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. 


“Heli-coils®” vs. “Keenserts®”: 3 differences you must know-Part 1 of 2 (Refreshed for 2023)

Today we will re-introduce you to our blog, “Heli-coils®” vs. “Keenserts®”: 3 differences you must know-Part 1 of 2, published back on 2020. We will compare these two fastener products that are used to repair damaged threads & threaded holes, or to strengthen/reinforce a weaker parent material like aluminum. Both Helical Wire Inserts & Key-locking Inserts are commonly used in precision manufacturing, transportation and aerospace applications. Their versatility, however, ensures their presence in nearly every industry that utilizes threaded fasteners.

What are the main uses of Threaded inserts?

Both “Heli-coil®” or Helical wire inserts and “Keensert®” or Key-locking inserts fall under the “Threaded Insert” category of fasteners.

Threaded insert, also known as a threaded bushing, is an insert that has internal threads, and is fastened into an object to add or reinforce a threaded hole.  Threaded inserts may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thread on a material too thin to accept it, mold or cast threads into a work piece thereby eliminating a machining operation, or simplify changeover from unified to metric threads or vice versa. Although Helical Wire inserts and Key-locking externally threaded inserts are used in similar ways, there are 3 main distinctions that we detail below. But first, let’s take a closer look at each of these fasteners:

What is a Helical Insert Wire Insert? (aka Heli-coil®)

Helical wire inserts are precision-formed continuous wire coils that provide permanent, wear-resistant threads which exceed the strength of the parent material. Often underestimated, the popular misconception is that Helical wire inserts are intended solely for thread repair, when, in fact, they have other significant uses.  Not to be confused with other types of threaded inserts or rivnuts, Helical wire inserts resemble springs and are sometimes referred to as “Screw Thread Inserts (STI)” ,“Helicals” or by the popular brand “Heli-Coil®” which is a registered trademark of Emhart® Teknologies, Inc.

Three typical applications for using Helical wire inserts are:

  • to repair damaged threads in parts that would otherwise have to be scrapped
  • to strengthen threads against failures due to stripping, seizing or corrosion
  • to convert threads between inch and metric sizes

What is a Key-locking insert? (aka Keensert® or Keysert®)

The Key-locking threaded insert is a solid bushing style insert that is threaded on both the inside and the outside and has wedges or “keys” attached to the top of the insert. These externally threaded inserts are used to distribute loads and repair or strengthen threads against failures due to stripping, seizing or corrosion. Key-locking inserts are commonly used in high torque and high temperature situations, and in applications where fasteners may be repeatedly removed and reassembled. Key-locking inserts are often referred to as Keenserts® and Keyserts®, which are registered trademarks for the most popular brand names for this part. (Keensert® is a registered trademark of Huck Patents, Inc. & Keysert® is a registered trademark of Alcoa Fastening Systems).

Typical applications are transmission housings, electronic equipment and suspension units. Key-locking inserts are commonly found in aerospace assemblies.

How do they work?

Helical wire inserts work because the diamond shaped helically formed wire coil screws into a threaded hole to form a mating internal thread for a screw or stud.  

Key-locking inserts are threaded into a pre-tapped hole, and then the keys are hammered into grooves through the threads, permanently locking the insert in place. Their “keys”, which are driven down into the tapped threads, provide a mechanical lock against rotation, especially when the mating stud or bolt will be removed frequently.

What materials, sizes and styles are available?

Key-locking Inserts/ Keenserts®

Key-locking inserts come in four main styles: Miniature, Thin Wall, Heavy Duty Wall (general purpose) and Extra Heavy Duty.

  • Miniature Key-locking inserts are used in electronic and aerospace applications where size and strength are critical. These inserts may be installed in sheet material as thin as 1/16″.
  • Thinwall inserts have smaller external threads than standard heavy-duty inserts and are ideal for tight spaces where less pull-out strength is acceptable.
  • Heavy Duty inserts have a thick, heavy-duty thread wall, suitable for most applications.
  • Extra-heavy duty inserts are used in oversized and overly worn holes.

Key-locking inserts can be internally self-locking or non-locking (the standard is non-locking and is sufficient for the most common applications).

Inserts with the internal self-locking feature are designed to securely lock a bolt when it is entered into the insert only a few turns. Even after repeated installations and removals of the bolt, the lock maintains sufficient locking torque to prevent the bolt from vibrating out.

Common Materials available include Carbon steel, Stainless Steel, Alloy 4140 and A286. Nitronic and other materials may be available with a lead time.

Internal Diameters available: American/Inch #2-56 to 1 ½-6 ” and Metric M2 to M24

Helical wire inserts / Heli-Coils®

Helical wire inserts come in 2 main styles: tanged and tangless (currently, MF Supply specializes in the tanged style).

The original and widely used tang style has a prong at one end to facilitate installation. The newer tangless style has no prongs to break off, retrieve, or lose. Tangless inserts are commonly used in electronic applications where loose tangs are might cause damage.

Helical wire inserts can be free-running or self-locking.

Free running is the most common style used for thread repair. The “free” diameter of the insert is larger than the installed diameter and this configuration generates balanced pressure distribution between the coils and threads.

Self-locking style inserts are recommended for applications that require constant torque, or are subject to stress or vibration. The locking style features a crimped turn that acts as a locking mechanism that grips the bolt or screw to prevent loosening from vibration, eliminating the need for lock wiring, lock-nuts, lockwashers, pellets/patches or other thread locking devices.

Common Materials available include Stainless Steel, Phosphorous Bronze, Inconel X-750 and Nitronic 60 and 90.

Internal Diameters available: American/Inch #2-56   to   1 ½-6” and and Metric M2   to   M24.  Standard inserts lengths measure from 1x to 3x the diameter. Note: larger sizes may be available by special order.

Why use a Key-locking insert vs. a Helical wire insert?

There are three main differences between Key-locking inserts and Helical wire inserts:

1) Strength: Key-locking inserts are stronger than Helical wire inserts

2) Ease of installation: Key-locking inserts are easier to install than Helical wire inserts

3) Price: Key-locking inserts are more expensive than Helical wire inserts!

So here is some direction on how to select the correct threaded insert for your application:  In heavy wear, high vibration and high heat situations where saving space is not a concern and hole depth is limited, Key-locking inserts are the best bet.

When reducing costs and minimizing space are priorities, Helical wire inserts are the way to go. They are particularly useful for creating permanent strong threads in softer materials such as aluminum, titanium and magnesium alloys, and are best suited to lower heat and lower torque environments.

Stay tuned for our next blog, where we discuss, brands and mil-spec options, how to order and installation options!

Key-locking Inserts (Keenserts®) & Helical Wire Inserts at MF Supply

MF Supply is a WBE/WOSB woman owned business, and a trusted supplier of Keenserts & Helical Wire Inserts for manufacturers, government and industry.

We Invite You To Request a Quote, Download a Guide or a Line Card Today!

  • Full ecommerce enabled website with technical manual available 24/7
  • Same day drop ship from factory for thousands of items.
  • Functional Equivalents to expensive brand name fasteners save money and reduce long lead times.
  • Creatively solve problems including hard to find parts and long lead times
  • WBE/WOSB Woman Owned Certified Small Business.

Do you still have questions or would like to speak with a representative to request a quote? 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, 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. 


Coiled Spring Pin!? What the heck is that?

Welcome back to 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. Today, we will introduce you to the Coiled Spring Pin! This mighty Non-Threaded Fastener, AKA Spiral Pin or Coiled Pin, is small in size, but it offers remarkable effectiveness in fastening and securing a wide range of components. The coiled structure of this fastener grants it flexibility and resilience, which in turn enables it to absorb shock, vibration, and lateral forces effectively. In general, this fastener is self-retaining, and will stay in place once installed;. This eliminates the need for additional retaining devices, simplifies the assembly process, and can reduce overall costs.

What are Coiled Spring Pins?

Also known as Spiral Pins or Coiled Pins, Coiled Spring Pins are headless & hollow pins with chamfered ends. They are usually made by shaping or wrapping a steel sheet into a slightly larger diameter than the standard size. This, in turn, results in a coiled design that allows them to distribute forces evenly along their entire lengths, mitigate stress concentration at specific points, and diminish the likelihood of component failure or fatigue when in use.

These pins are frequently used to join and fasten two or more components together. When the pins are inserted into pre-drilled holes, their spiral shape allows them to expand and exert radial pressure against the sides of the hole, which in turn creates a precise and secure connection. This is particularly crucial in applications subject to constant movement, such as machinery and automotive systems.

The versatility, ease of installation, and distinctive design distinguish Coiled Spring Pins from other pins in the same category. This is because, apart from their fastening functionalities, these pins can also serve as effective retaining features. They have the ability to secure various items, such as gears, pulleys, or bearings, onto shafts, effectively preventing axial movement or slippage. Hence, whether utilized in machinery, automotive systems, electronics, or countless other applications, Coiled Spring Pins excel in delivering dependable, long-lasting, and cost-effective solutions.

Who uses Coiled Spring Pins?

Due to their dependable nature and versatility, Coiled Spring Pins are extensively utilized across various industries and applications. Here are some of the industries where coiled spring pins are commonly used:

  • Aerospace Industry: In the aerospace industry, Coiled Spring Pins play a vital role in applications that require reliable fastening and long-lasting durability. They are utilized in aircraft structures/frameworks, electronic components, circuit boards, landing gear, engines—where Coiled Spring Pins play a crucial role in guaranteeing the secure attachment of vital components like turbine blades, compressor parts, and fuel system components—and other crucial systems. These pins demonstrate excellent resistance to vibration, fatigue, and extreme temperature variations, making them highly suitable for demanding aerospace applications.
  • Automotive Industry: Coiled Spring Pins are an integral part of the automotive industry. These pins are used in critical components such as brake systems, engine assemblies, transmissions, suspension systems, etc. Their exceptional capability to withstand high forces, resist loosening due to vibrations, and deliver dependable connections makes them highly suitable for the rigorous demands of automotive environments.
  • Electronics and Electrical Industries: Coiled Spring Pins hold significant importance within the electronics and electrical industries. They are essential for securing connectors, circuit boards, switches, and a range of electronic components. These pins ensure dependable electrical connections, protect against damage caused by excessive movement or shock, and withstand the thermal demands typically associated with electronic devices.
  • Defense and Military: Coiled Spring Pins are used in defense and military applications because of their exceptional reliability and durability. These pins are deployed in crucial systems such as military vehicles, weapons, and communications equipment. Their capability to withstand extreme conditions and ensure secure connections in demanding environments is vital for successful military operations.

Other industries that make use of Coiled Spring Pins include: the Medical Industry, where this pins are used to provide secure connections to surgical instruments, orthopedic implants, dental equipment, and diagnostic tools; the Consumer Goods Industry, where these fasteners are used in furniture, locks, hinges, power tools, toys, and other items that require secure and durable fastening; and the Machinery and Manufacturing Industries, where these pins provide secure fastening solutions for components such as gears, pulleys, shafts, and bearings.

What standards, materials and sizes are available?

Coiled Spring Pins are readily available off the shelf in Steel, with a Thermal Black finish, and in series 420 Stainless Steel.  Standard stock sizes for the head diameter are Inch from 1/16 to 3/8, and length from 1/4 to 3.

Commercial Standards include:

  • Inch: ASME B18.8.2, ASME B18.8.3M
  • Metric: ISO8748, ISO8750, ISO8751

Mil-Spec standards include:

  • MS39086, MS51923, MS51987, NAS1407, NAS561

Are there other factors to consider?

YES!! Installing Coiled Spring Pins requires a few essential tools to ensure proper placement and secure attachment. Below are a few tools that you might need in order to properly install them on a desired application.

  • Hammer/Mallet: To safely and accurately drive the Coiled Spring Pin into position, without causing distortion or deformation, it is necessary to use a hammer or a mallet, and to gently strike the coiled spring pin into position.
  • Pin Punch Tool: A pin punch tool could be used to drive the Coiled Spring Pin into a pre-drilled/tapped hole. This tool guarantees precise alignment and prevents any potential damage to the pin during the installation process.

Coiled Spring Pins at MF Supply

We currently offer:

  • A full range of commercial parts, including parts that are ROHS compliant.
  • Inch Coiled Spring Pins are now available for online purchase at our website!
  • Please send a Request for Quote for your Mil-Spec and Metric series needs.
  • Brand names and generic equivalents.
  • Custom made parts per print.

For more detailed information on Coiled Spring 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. 


Over 1.5K Dowel Pins, Cotter Pins, Spring Pins, and more Now in Stock!

Are you looking for Precision Dowel Pins, Cotter Pins, Spring Pins or Hair/Hitch Pin Clips?

If you are in need of any specific type of pins or clips for your next big project, you have arrived at the right place!

MF Supply is a WBE/WOSB woman owned business, and a trusted supplier of Functional Equivalent Pins & Clips to OEMs, Manufacturers, Industry, and Government. We offer a wide selection of over 1,500 inch, metric & Mil-Spec Pins, in Alloy Steel, Steel, and Stainless Steel materials, that are perfect for a myriad of applications. You’ll find in stock Pins in many sizes including major brands and equivalents to Blue Devil, Pic Design, WM Berg, Misumi and Unicorp; so you can choose the ones that best suit your needs.

Who uses Pins & Clips?

Pins & clips are commonly used on many industries, such as automotive, aerospace, electronic, machinery, tooling, agriculture, construction and many more where reliable and convenient fastening is a must. Continue reading to learn more about the characteristics of each pin or clip currently on our website, and how they could be of use on your next project.

Coiled Spring Pins: Coiled Spring Pins, also known as Spiral Pins or Coiled Pins, are headless, hollow pins with chamfered ends, made by shaping or wrapping a steel sheet into a slightly larger diameter than the standard size. Unlike the slotted pins variety, these pins are distinguished by their multiple walls.

Uses: These pins are frequently used to join and fasten two or more components together. When the pins are inserted into pre-drilled holes, their spiral shape allows them to expand and exert radial pressure against the sides of the hole. This creates a secure and snug fit/connection. Apart from their fastening functionalities, Coiled Spring Pins can also serve as effective retaining features. They have the ability to secure various items, such as gears, pulleys, or bearings, onto shafts, effectively preventing axial movement or slippage. Moreover, these pins can be utilized to accurately position and retain other components, ensuring precise alignment and preventing undesired movement.

Cotter Pins: Cotter Pins, also known as Split Pins, are double bodied pins formed from half-round wire, a loop at one end of which provides a head. The finished part has one end of the wire extending beyond the other end, with a chiseled point.

Uses: These pins are used to anchor various assemblies by inserting them into a drilled hole in the shaft or pin and spreading the points to hold the assembly in position. When used with castle or slotted nuts, it becomes a safety locking device. An 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 readily taken out by straightening or bending back the split end to its original position. This feature simplifies repair or maintenance operations.

Precision Dowel Pins: These pins are solid headless straight pins with a closely controlled diameter. Applications include a wide variety of uses, such as plug gage, hinge, or shaft. They are typically cylindrical in shape and made from materials such as hardened steel, stainless steel, or aluminum.

Uses: Precision Dowel Pins are widely utilized to achieve precise alignment and positioning of components. These pins undergo meticulous machining processes and are manufactured with strict tolerances to guarantee a snug and accurate fit. Precise tolerances of Dowel Pins make them excellent for achieving proper alignment of parts in high-speed assemblies, or as roller bearings in bus/truck wheel housings. By inserting them into corresponding holes in two or more parts, the dowel pins guarantee proper alignment and positioning of the parts in relation to one another. These dowel pins serve as reference points or datums, ensuring accuracy and precision throughout the assembly process.

Slotted Spring Pins: Sometimes referred to as Roll Pins, Expansion Pins, C-Pins or Tension Pins, Slotted Spring Pins are hollow, headless pins, slit longitudinally, having controlled lengths with chamfered ends, formed to a diameter somewhat greater than that of the hole into which they are to be assembled. These pins are cylindrical in shape and are able to compress and expand upon insertion into a hole. Additionally, they are commonly crafted from materials such as carbon steel or stainless steel.

Uses: Slotted spring pins are used for the purpose of securing and fastening components together. The slots present in the pin allow for compression during insertion and radial expansion, which generates outward pressure against the walls of the pre-drilled hole. This inherent self-retaining characteristic guarantees the pin’s retention and delivers a secure method of fastening. Spring pins are economical because they can simplify product design by replacing more expensive fasteners such as taper pins, set screws and straight pins. Stainless steel Spring Pins are commonly used in electronics and food industries.

Hair/Hitch Pin Clips: Hitch Pin Clips, also known as Hair Pin Clips, Bridge Pins or R-Clips, are double-bodied pins formed from round wires. These pins are formed in a way where one end is bent approximately 180° so that the two resulting sides meet or come close to meeting. The final pins have one side that remains straight, while the opposite side has one or more turns permanently formed into it.

Uses: Hair/Hitch Pin Clips are designed to serve as a mating part to several other pins. They provide a hassle-free way to attach and detach components without the need for additional tools or complicated fastening mechanisms. Hitch Pin Clips also act as a safety feature, ensuring that the connected components remain intact during operation. When the need arises to remove or replace a pin, Hitch Pin Clips present a simple and time-saving solution. By simply compressing the curved end and sliding it out of the hole, the clip can be easily removed. Hence, this allows for quick disassembly, maintenance, or component replacement without the requirement of specialized tools or lengthy procedures.

In-Stock Pins & Clips at MF Supply

We currently have in stock over 1,500 Pins & Clips in inch, metric & Mil-Spec sizes. The most common material options available are: alloy steel with bright or ebony black oxide finishes; steel with thermal black, mechanical zinc, zinc, and zinc phosphate finishes; and passivated stainless steel—including series A2, T321, 18-8, 300, 303, 316, 400 416, & 420.

Browse through the links provided below to find the Pins or Clips that you need, and that are currently available on our website.

  • Inch Coiled Spring Pins: Stock sizes include 1/16 to 3/8 in Steel with a Thermal Black finish, and in 420 Stainless Steel.
  • Inch Cotter Pins: Stock sizes include 1/16 to 1/2 in Steel with a Chisel Point and Zinc Plating, as per standard ASME B18.8.1 specifications.
  • Mil-Spec MS9245 Cotter Pins: Stock sizes include 1/32 through 5/32 in T321 Stainless Steel.
  • Inch Precision Dowel Pins: Interference / Press Fit & Slip Fit Dowel Pins in 300 Series Stainless Steel; Dowel Pins in 316 Series Stainless Steel; and Dowel Pins in Alloy Steel with Bright or Ebony Black Oxide finishes.
  • Metric Precision Dowel Pins: Stock sizes include M1 through M10 diameters in 18-8, 300, 303, A2 Series Stainless Steel; and M2 through M10 diameters in 416 Stainless Steel.
  • Mil-Spec Precision Dowel Pins: MS16555-1 through MS16555-145, MS16555-301 through MS16555-444 & MS16555-601 through MS16555-744, including between-spec sizes; and Mil-P-21143 Series in 303 Stainless Steel.
  • Inch Slotted Spring Pins: Stock sizes include 1/16 to 1/2 in Steel wth a Thermal Black or Mechanical Zinc Finish, 420 Stainless Steel, and Stainless Steel materials—as per standard ASME B18.8.2 specifications.
  • Metric Slotted Spring Pins: Stock sizes include M2 to M8 in Steel with a Thermal Black Finish, as per standard ISO 8752 specifications.
  • Mil-Spec MS16562 Slotted Spring Pins: Stock sizes include 1/16 through 1/2 in Steel Zinc Phosphate.
  • Inch Hair Pins / Hitch Pin Clips: Stock sizes include .028 to .243 in Steel Zinc.

Our Pins & Clips are competitively priced. Don’t wait! Visit our website today to place an order, or Request a Quote and we will follow up with you.

Can’t find what you’re looking for?

Can’t find what you are looking for on the list? Reach out to us today, and 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!


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. 


Over 2.6K Plastite® & Taptite® Alternative Screws Now in Stock!

Are you looking for Plastite® or Taptite® Brand Generic Alternative Screws?

If you are in need of Trilobular Plastite® or Taptite® Alternative Screws for your upcoming project, you have arrived at the right destination!

MF Supply is a WBE/WOSB woman owned business, and a trusted supplier of Functional Equivalents to Plastite® and Taptite® Brand screws. We offer a wide selection of over 2,600 inch and metric trilobular thread-rolling / thread-forming screws, in Steel or Stainless Steel materials, that are perfect for a variety of plastic/thermoplastic and soft metal applications. You’ll find in stock Plastite® and Taptite® Alternative Screws with different head styles, drives, thread sizes, and lengths; so you can choose the ones that best suit your needs.

Common Uses for Plastite® Alternative Screws

Plastite® Alternative Screws are used in many industries that rely on fastening solutions for plastic/thermoplastic applications. The main purpose for these screws is to create threads within the plastic material, as they are being driven in, in order to create dependable and secure fastening solutions for holding plastic components together.

Some of the industries that benefit from Plastite® Alternative Screws include the Consumer Goods Industry, where they utilize this fastening solution to secure plastic parts in furniture, plastic containers, toys, and sporting goods; the Appliances Industry, where these screws are used to assemble many plastic parts/components that contribute to the overall durability and functionality of the appliances, such as dishwashers, dryers, washing machines, refrigerators, and many other household appliances; the Electronics and Electrical Industries, where these screws are touted for their resistance to loosening due to vibration, and for their fastening use in circuit boards, cable management systems, electrical components, and other plastic surfaces. In addition to the previous industries, the Industrial Equipment Industry, Automotive Industry, Packaging Industry, and many more, also make great use of these handy fasteners!

Common Uses for Taptite® Alternative Screws

Taptite® Alternative Screws carry similar benefits to the ones Plastite® Alternative Screws offer, but with the added benefit that they can also be used on soft metal applications, such as aluminum, mild steel, brass, copper and magnesium. In this sense, these screws are used in many industries where secure and efficient fastening is a must!

Some of the industries that make use of Taptite® Alternative Screws are: the Aerospace Industry, where they use these screws in components that require resistance to vibration, such as aircraft components, and aerospace structures and equipment; the Electronics Industry, where they use many of these screws to secure electronics, such as smart phones, computers, circuit boards, electronic enclosures, and other consumer electronics; the Metal Fabrication Industry, where these guys do the job of fastening metal assemblies and metal structures securely in place. Other industries that make use of these screws are the Manufacturing and Assembly Industry, the Automotive Industry, and the Machinery and Equipment Industry—where Taptite® Alternative Screws are commonly used in the assembly of construction equipment, industrial and agricultural machinery, and other mechanical systems.

In-Stock Plastite® & Taptite® Alternative Screws at MF Supply

We currently have in stock over 2,600 Plastite® and Taptite® Alternative Screws in inch and metric sizes, and in a variety of head styles, drives, and lengths. The most common material options available are: steel—with a black oxide, black zinc, zinc, zinc green, or zinc yellow finish—A2 Steel, 410 stainless steel, and stainless steel materials.

Below is a list of the Trilobular Thread-Rolling / Thread-Forming Plastite® and Taptite® Alternative Screws currently available on our website!

Our Plastite® and Taptite® Alternative Screws are competitively priced. Don’t wait and visit our website today to place an order, or reach out to us to Request a Quote!

Can’t find what you’re looking for?

Can’t find what you are looking for on the list? Reach out to us today, and 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!


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. 


Taptite® Alternative Screws!? What the heck are those?

Welcome back to the next installment in our “what the heck is that” series, refreshed for 2023! In this series we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. Today, we will introduce you to Taptite® Alternative Screws! Like our friends, the Plastite® Alternative Screws, these fasteners are functional equivalents to a trademark registered branded product. Taptite®, Duo-Taptite®and Taptite Pro® are trademarked by REMINC/CONTI.

What are Taptite® Alternative Screws?

Taptite equivalent fasteners are high performance thread-rolling screws (sometimes called thread-forming or trilobular) that create reusable threads in soft metal materials, such as plastic, aluminum, mild steel, brass, copper and magnesium. Their design include a trilobular rolling or thread-forming tip that grants them thread-forming, thread-rolling action as they are driven into the material. This thread-forming action creates a tight and secure connection, which in turn enhances the holding power of the screws in the plastic and soft metal component.

These fasteners need pre-drilled holes, but they don’t need pre-tapped or pre-threaded holes. This is because, when their threads are driven into the application, they tend to displace the material on the walls, inside the holes, in order to form mating threads. These newly formed internal mating threads tighten the screws securely in place and provide resistance to loosening caused by vibrations. Hence, Taptite® Alternative Screws are designed for applications where stability is crucial, but also to help eliminate some of the assembly costs associated with tapping procedures.

It is also worth mentioning that Taptite Alternative screws come in inch & metric sizes, and in a variety of heads, drives, materials and finishes that are designed for a wide range of plastic and soft metal fastening solutions.

Who uses Taptite® Alternative Screws?

Taptite® Alternative Screws are designed with an optimized thread-forming / thread-rolling action that enables efficient engagement, provides increased holding power, clamp load retention, and resistance to loosening due to vibrations. Any plastic or soft metal application with a pre-drilled bore/hole that needs to reliably secure the mating of components, and that needs to eliminate the need for additional tapping, threading or locking operations is a great candidate for using this type of fasteners!

Taptite® Alternative Screws are widely used across various plastic and soft metal applications in many industries, including: aerospace, electronics, appliances, manufacturing, machinery and equipment, and many more. They are also very common in the automotive industry. For instance, many manufacturers have used these screws to assemble components onto the exterior and interior of aluminum engines.

What materials and sizes are available?

Taptite® Alternative Screws are readily available off the shelf in steel—with a black oxide, black zinc, zinc, zinc green, or zinc yellow finish—410 stainless steel, and stainless steel materials. In addition, inch Taptite® Alternative Screws follow the SAE J81 standard, and their metric counterparts follow the Din 7500 standards.

Standard stock sizes for the head diameter are Inch from 2-56 to 1/2-13, and Metric from M2-0.4 to M8-1.25. Popular thread classes include partial, SEMS, and full threads.

Are there other factors to consider?

YES! It is generally recommended to pre-drill or pre-punch holes, with an increased length of engagement, to hold the entire length of the screws in the plastic or metal material/application. This should be done in order to ensure proper thread formation, fastener fracture—if it is the preferred failure mode—and to minimize the risk of material damage.

Taptite® Alternative Screws at MF Supply

We currently offer:

  • A full range of commercial parts, including parts that are ROHS compliant.
  • Inch and Metric Din 7500 Taptite® Brand Generic Alternative Screws are now available for online purchase at our website!
  • Brand names and generic equivalents.
  • Custom made parts per print.

For more detailed information on Taptite® Alternative Screws or other Trilobular Thread-Rolling / Thread-Forming 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. 


Plastite® Alternative Screws? What the heck are those?

Welcome back to 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 introduce you to the Plastite® Alternative Screws. This fastener creates reusable threads in plastics. It goes by many monikers, and is AKA as a Thread-forming,  Thread-Rolling, Trilobular, and sometimes thread-cutting screws. Plastite® Alternative Screws require a drilled or punched hole to install.  In general, thread-forming screws press threads into material for a tight, vibration resistant assembly, while thread-cutting screws require less driving torque and cause less stress on material than thread-forming screws.

What are Plastite® Alternative Screws?

Plastite® Alternative Screws are trilobular thread-forming / thread-rolling screws specifically designed for plastic and thermoplastic applications. Their design include a cutting or thread-forming tip that grants them thread-forming, thread-rolling action as they are driven into the plastic material’s hole.

These fasteners do not need pre-tapped or pre-threaded holes because, when their threads are driven into the plastic application, they tend to displace the plastic within the internal sides of the hole and form a female thread. This newly formed internal thread is then used against the male thread of the screw to tighten it, with the right driver’s torque, securely in place.

It is also worth mentioning that they come in a variety of heads, drives, materials and finishes that are designed for specific or unique plastic and thermoplastic fastening solutions.

AKA – Also known as…..

Plastite® Alternative Screws are also called Plas-Fix®45 Alternative, Plastite® Alternative and EJOT® PT® Alternative Self-Tapping Screws. They are designed with an optimized thread-forming / thread-rolling action that enables efficient engagement and provides increased holding power when used exclusively in plastic applications.

Who uses Plastite® Alternative Screws?

Any plastic or thermoplastic application with a bore/hole that needs to reliably secure the mating of plastic components, and that needs to eliminate the need for additional tapping or threading operations is a great candidate for using this type of fasteners!

Plastite® Alternative Screws are broadly used across various plastic and thermoplastic applications in many industries, including: electronics, electrical engineering, packaging, appliances, industrial assemblies and equipment, and many more. Plastite® Alternative Screws are also very common in the automotive industry for fastening some of its plastic components, such as dashboard assemblies, door panels, and engine compartments.

What materials and sizes are available?

Plastite® Alternative Screws are readily available off the shelf in steel—with a black oxide, black zinc, zinc or zinc yellow finish—A2 stainless steel, 410 stainless steel, and stainless steel materials. In addition, some of these screws also follow the ASME B18.6.3 standard.

Standard stock sizes for the head diameter are Inch from #0-40 to #5/16-9, and Metric from M1.6-0.67 to M6-2.5. Popular Metric thread classes include full 30 & 45 degree thread flank.

Are there other factors to consider?

YES! It is generally recommended to pre-drill or pre-punch holes, that are deep enough to hold the entire length of the screws, in the plastic material/application. This should be done in order to ensure proper thread formation and minimize the risk of material damage.

Popular brands include: Plastite®, Plas-Fix®45 and EJOT® PT®.

Plastite® Alternative Screws at MF Supply

We currently offer:

  • A full range of commercial parts, including parts that are ROHS compliant.
  • Inch and Metric parts are now available for online purchase at our website!
  • Brand names and generic equivalents.
  • Custom made parts per print.

For more detailed information on Plastite® Alternative Screws or other Trilobular Thread-Rolling / Thread-Forming 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. 


How Precision Shoulder Screws are Used in Robotics and Automation

Precision shoulder screws have become an indispensable component in the realm of robotics and automation. Their unique design, combining the functionality of a fastener and a shaft, empowers engineers to achieve precise positioning, smooth motion, modularity, and stability within robotic systems. By incorporating shoulder screws, designers can elevate the performance of robots, making them more reliable, accurate, and adaptable to meet the growing demands of various industries. In this blog, we will explore how precision shoulder screws are used in robotics and automation, and what factors to consider when purchasing them for industrial applications.

What are Precision Shoulder Screws?

Precision shoulder screws are a type of fastener designed with a cylindrical shoulder that provides precise alignment and support, making them ideal for use in applications that require accurate positioning and secure attachment.

When selecting these screws for industrial applications, it is important to consider factors such as material, size and thread type, head type, and application requirements to ensure that the screws provide the necessary strength and support, and can withstand the forces and stresses involved in the application. With the right precision shoulder screws, robotics and automation applications can operate with precision, accuracy, and reliability. Our handy Buyer’s Guide (link to guide)can direct you to the most common off the shelf available options.

Precise Positioning & Alignment

One of the primary benefits of precision shoulder screws is their ability to provide precise alignment in robotic and automation applications. The shoulder of the screw acts as a guide for the mating component, ensuring that it is aligned precisely and securely. By using shoulder screws, engineers can achieve tight tolerances, eliminating any unwanted play or misalignment that could compromise the robot’s performance.

Secure Attachment

Another key benefit of precision shoulder screws is their ability to provide secure attachment. The shoulder of the screw creates a stop against the mating component, preventing it from moving or rotating. This is important in applications that involve high levels of vibration or stress, as it ensures that the components remain securely attached and in place.

Smooth and Reliable Motion

In robotics, smooth and reliable motion is essential for efficient and accurate operations. Precision shoulder screws facilitate this by reducing friction and ensuring smooth movement between connected parts. The shoulder section acts as a bearing surface, minimizing wear and tear while allowing the robot to perform intricate tasks with minimal resistance. This enhanced motion control enables robots to execute precise actions, such as pick-and-place operations, assembly tasks, or complex maneuvers, with exceptional accuracy.

Modularity and Flexibility

Robotic systems often require modular designs, allowing for easy maintenance, upgrades, or customization. Precision shoulder screws excel in such scenarios due to their modular nature. By utilizing shoulder screws, different components can be connected and disconnected swiftly and securely. The screws enable the easy removal and replacement of specific parts or modules, providing a flexible platform for reconfiguration or adaptation to changing operational requirements.

Vibration Damping and Stability

In many robotic applications, vibrations can adversely affect performance and accuracy. Precision shoulder screws play a vital role in dampening these vibrations and maintaining stability. The shoulder section acts as a barrier, absorbing and dissipating vibrational energy, thus reducing the impact on the overall system. This feature is particularly crucial in high-speed or precision-focused robots where even slight disturbances can lead to errors or malfunctions.

Conclusion: Precision shoulder screws have become an indispensable component in the realm of robotics and automation. Their unique design, combining the functionality of a fastener and a shaft, empowers engineers to achieve precise positioning, smooth motion, modularity, and stability within robotic systems. By incorporating shoulder screws, designers can elevate the performance of robots, making them more reliable, accurate, and adaptable to meet the growing demands of various industries.

How to order

Precision Shoulder Bolts often show up under their OEM 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.

Check out our Buyer’s guide for more info.

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.