Top 17 Keensert® Questions: Expert Answers to Common Questions (Part 3)

In the final installment of our Top 17 Keensert® Frequently Asked Questions series, we’re diving into some of the most advanced topics in the world of key-locking inserts. We’ll compare Keensert® style inserts with alternatives like Helical Inserts (Heli-Coils®), explore the unique advantages of floating key-locking designs, unpack the performance benefits of dry film lubrication, and explain why high-performance materials such as A286 superalloy may come with longer lead times. Our aim is to equip manufacturers with the knowledge they need to make confident, informed procurement decisions.

13. What is the difference between a Keensert® and a Heli-coil®?

Both “Heli-coil®” or helical wire inserts and “Keensert®” or key-locking inserts fall under the “Threaded Insert” category of fasteners. Both helical wire and key-locking inserts are used to repair damaged threads or to strengthen/reinforce a weaker parent material.

A key-locking insert (Keensert®) is a solid bushing style insert that is threaded on the inside and the outside with keys on the top. A helical wire insert (Heli-coil®) is a spring-like precision form wire coil that provides a permanent thread that’s stronger than the parent material.

The main differences between helical wire inserts and key-locking inserts lie in their strength, ease of installation and price.

Here are some directions on how to select the correct threaded insert for your application:

• Keenserts are the best bet in heavy wear, high vibration and high heat situations where saving space is not a concern and the hole depth is limited.
• Helical wire inserts are the way to go when reducing costs and minimizing space are priorities. Helicals are useful for creating permanent strong threads in softer materials, in lower heat and lower torque environments, or to convert threads between inch and metric sizes.

Checkout our blog, “Heli-coils” vs. “Keenserts”: 3 differences you must know-Part 1 of 2, to learn more!

14. Which Keenserts® have dry film lube?

Dry film lube is a lubricant applied to reduce friction, which is available on some Keenserts® for applications requiring reduced torque or where liquid lubricants are impractical.

Note: Self-locking Keenserts® are often treated with a dry-film lubricant that makes them easier to install and can result in a darker appearance compared to non-self-locking types.

15. What are floating Keenserts® used for?

Floating Keenserts® allow for slight misalignment in bolt holes. They’re not typically off-the-shelf due to their specialized application, often requiring a custom order with a minimum buy and a lead time.

16. Why is there such a long lead time on A286 Keenserts®?

Compared to more commonly used materials such as carbon steel and stainless steel, A286 has a limited pool of suppliers. Keenserts® made from A286 superalloy are known for their strength and corrosion resistance at high temperatures, which makes them ideal for many aerospace applications. However, due to their specialized nature, the availability of A286 Keenserts may be limited and may involve longer lead times and minimum buys compared to other more common materials. Plan accordingly.

17. What is the difference between Keysert® and Keensert®?

Keysert® and Keensert® are both brand names for key-locking inserts. Keensert® is a registered trademark of Huck Patents, Inc. & Keysert® is a registered trademark of Alcoa Fastening Systems.

You now have a comprehensive understanding of the advanced features and practical considerations that drive strategic decisions when sourcing for Keensert® style inserts. From material selection and installation nuances to balancing cost and efficiency with alternatives like Helical Inserts (Heli-Coils®), these insights empower you to make informed, strategic decisions when sourcing Keenserts® for your projects.

At MF Supply we specialize in supplying Keensert® Style Threaded Inserts to manufacturers, industry, and government, including major brands and equivalents to Acme, Alcoa, Camloc, Clarendon, Fairchild, Kaynar, Microdot, Tridair Keenserts®, Chrislynn, McMaster-Carr, Carr-Lane, Jergens, Howmet & Keyserts. Where applicable, our products are DFAR compliant with COC and full certifications available upon request.

If you have any questions, feel free to connect with our team or send us a request for quote and our team of sourcing experts will help you find what you need. “Finding the right screw for you” is our tag line after all!

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.

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

Top 17 Keensert® Questions: Expert Answers to Common Questions (Part 2)

In this second part of our three-part series, Top 17 Keensert® Frequently Asked Questions, we dive deeper into selecting the ideal key-locking inserts (a.k.a. Keenserts®) for your specific application. We’ll cover available insert materials—ranging from stainless steel and carbon steel to specialty alloys like 4140—and explain key sizing and thread-fit considerations. You’ll discover why key-locking inserts feature slightly oversized OD, and whether different lengths are available for various sizes. We will also share a simple visual trick that makes it easy to distinguish between self-locking and non-self-locking Keenserts®. Finally, we’ll offer practical advice for choosing the right key-locking insert material for your projects.

8. In what materials are key-locking inserts available off-the-shelf?

Key-locking inserts are commonly available off the shelf in carbon steel (black-phosphate steel) and 303 stainless steel. Additional materials include A4140, A286, and Nitronic 60, which may require a lead time and/or a minimum order.

Note: All sizes may not be available in all materials.

9. Do key-locking inserts come in different lengths?

Yes, key-locking inserts come in different lengths to accommodate various application requirements. The length of each key-locking insert is preset and is a function of the insert’s internal and external diameter. This ratio is usually determined by the manufacturer and can vary based on the thread size, material thickness, and the desired strength of the threaded connection.

Note: When selecting a key-locking insert, the length is usually chosen based on the thickness of the parent material and the load requirements. Thinwall key-locking inserts are often shorter, while heavy-duty or solid inserts may be longer to provide greater thread engagement and strength.

10. Why are the measurements of the outer diameters of Keensert® style key-locking inserts slightly larger than the standard UNC or UNF thread tolerances?

The outer diameter of key-locking inserts is slightly larger to ensure a tight fit and sufficient thread engagement in the parent material, compensating for tapped hole variations.

11. Why are self-locking Keenserts® a darker color than non-self-locking Keenserts®?

Self-locking Keenserts® are often treated with a dry-film lubricant that makes them easier to install and can result in a darker appearance compared to non-self-locking types.

12. How do I select the correct key-locking inserts material for my application?

The material choice for a key-locking insert depends on the application’s requirements, such as strength, corrosion resistance, temperature tolerance, parent material and environment. Generally speaking, 303 and Nitronic 60 stainless steel are more common for harsh environments, and carbon steel (i.e., black-phosphate steel) is used for general applications. We recommend reaching out to us or consulting a fastener engineer as a best practice.

Stay tuned for the next and final installment in this series, where we’ll cover advanced topics including how Keenserts® style key-locking inserts stack up against alternative threaded inserts, such as helical inserts (AKA HeliCoil®), and clarify common misconceptions.

Remember, expert advice is just a click away. If you have any questions, feel free to connect with our team or send us a request for quote and our team of sourcing experts will help you find what you need. “Finding the right screw for you” is our tag line after all!

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.

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