“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.

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Six Reasons To Buy From MF Supply

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

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 

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