Floating Keensert® Style Key-Locking Inserts — Ideal for Off-Center Holes
Posted: July 2, 2025 Filed under: Brand equivalents, Fasteners, Floating Keenserts, floating key-locking inserts, keensert, key-locking inserts, Threaded Bushing, Threaded Fasteners | Tags: Alloy Steel Floating Keenserts, Floating Inserts, Floating Keenserts, Floating Keenserts Distributor, Floating Keenserts Supplier, Floating Key Locking Inserts, Floating Keylocking Inserts, inch keenserts, Inserts, inserts for manufacturers, Keenserts, manufacturing, Stainless Steel Floating Keenserts, threaded bushing, threaded fastener Leave a commentMF Supply is an expert and a leading supplier of Floating Key-Locking Inserts—commonly known in the industry as Floating Keenserts®, Floating Key Locking Threaded Inserts, Floating Key Locking Inserts, and Floating Keylocking Inserts—for manufacturers, engineers, government and industry.
Shop Floating Keensert® Style Key-Locking Inserts at MF Supply!
In this blog, we will showcase a comprehensive overview of what Floating Keenserts® are, their benefits, where they are used, available styles, sizes, and materials—and when they’re the go-to solution for aerospace, defense, or demanding industrial manufacturing applications.
What Is a Floating Keensert®?

A Floating Keensert® is a specialized fastener engineered to correct and accommodate thread misalignments. The Keensert®, supplied as a one-piece unit, is ideal for use where mating panel holes may be off-center. Unlike the conventional rigid Keensert®, a Floating Keensert® integrates an internal floating nut element that “floats” within the insert’s outer housing. This unique floating feature allows internal threads to self-align during installation, reducing the risk of binding or misfit issues, which can occur with other Keenserts® or conventional threaded inserts.
This insert automatically compensates for misalignment:
- .015” for miniature size 2-56
- Up to .040” for heavy-duty size #10 and larger
In What Series, Sizes and Materials are Floating Keenserts® Available?
Floating Keenserts® are available in Miniature and Heavy Duty series—both in locking and non-locking options. Standard sizes and materials are noted below. Special materials, such as A286 Stainless Steel, may be available as a special order and may involve a lead time or a minimum.
Miniature Floating Keenserts® Series (KNK & KNKL)
- Sizes: Available in inch/imperial sizes ranging from 2-56 through 8-32 inches.
- Material: Crafted from 303 corrosion resistant stainless steel (CRES).
- Finish: Passivated.
- Keys: These inserts are furnished with two locking keys only.
- Tolerances: ±.010 inch unless specified otherwise.
Heavy Duty Floating Keenserts® Series (KNK, KNKD & KNKDL):
- Sizes: Available in inch/imperial sizes ranging from 10-24 through 1/2-20 inches.
- Material: Made from durable 4140 Alloy Steel.
- Finish: Cadmium Plating.
- Keys: These inserts are furnished with four locking keys for internal thread size of 5/16 and larger, and two locking keys for all smaller sizes.
- Tolerances: ±.010 inch unless specified otherwise.
Locking and Non-Locking Features
- Both, Miniature and Heavy Duty Floating Keenserts® feature self-locking options/variants, which are always denoted by an “L” in the series or product codes (e.g., KNKL0256J, KNKL, and KNKDL). These self-locking inserts are also treated with dry-film lubricant, which usually appear darker in finish than non-locking models, simplifying installation and providing amazing thread-locking capabilities.
Check out our Floating Keensert® Style Key-Locking Inserts cross-reference chart to find your ideal insert!
What Are the Benefits and Possible Applications for Floating Keenserts®?
Floating Keenserts® provide significant benefits by automatically compensating for thread misalignment, facilitating easier and more accurate fastener installations, and enhancing reliability in scenarios where standard rigid inserts could lead to thread binding, misalignment, or failure. Typical applications include:
- Curved surfaces where precise alignment is challenging
- Flat head screw/bolt installations
- Assemblies involving multiple hole alignments
- Environments subject to thermal expansion and contraction
Their one-piece assembly design ensures easy installation and optimal thread alignment, minimizing downtime and improving overall project reliability.
MF Supply Is Your Source for Floating Keensert® Style Key-Locking Inserts!
MF Supply is a WBE/WOSB certified business, and a leading supplier of Floating Keensert® Style Key-Locking Inserts for manufacturers, engineers, government and industry. At MF Supply, we understand the dynamic needs of the industry, including the balance of price, quality, availability and certification paperwork, such as DFAR and COC. Most popular sizes are in stock and ready to ship within 24 hours. Ready to see how we can help you?
Do you still have questions or would like to speak with a representative? Reach out to us or send us an RFQ below, 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.
Six Reasons To Buy From MF Supply
- Creatively Solve Problems – We are sourcing experts and specialize in hard to find parts. We offer custom manufacturing and reworking solutions at competitive pricing, reducing long deliveries.
- Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
- 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.
- 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, with an expertise in inserts, military fasteners and stainless steel hardware. 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.
Carbon Steel Key-Locking Inserts (AKA Keenserts®) at www.mfsupply.com
Posted: January 26, 2024 Filed under: Brand equivalents, Carbon Steel Keenserts, Fasteners, Inch and Mil-Spec Keensert, keensert, key-locking inserts, Metric Keensert, Threaded Bushing, Threaded Fasteners | Tags: Carbon Steel, Carbon Steel Keenserts, Carbon Steel Key-Locking Insesrts, Fasteners, inch keenserts, Inserts, inserts for manufacturers, Keenserts, manufacturing, metric keenserts, mil-spec keenserts, RKK, RKK Keenserts, threaded bushing, threaded fastener Leave a commentMF Supply is an expert and industry leader when it comes to key-locking inserts, commonly known by the popular brand name Keensert®. We stock and source key-locking inserts in a wide variety of materials, platings and sizes, including Inch, Metric, Commercial and Mil-Spec options.
In today’s blog, we will showcase a comprehensive overview of Carbon Steel Key-Locking Inserts, covering their benefits, uses, styles, standards, sizes, and comparison with other key-locking inserts made from other materials — so you are all set before jumping off to procure them for your next project.
What are Carbon Steel Key-Locking Inserts?

Carbon Steel Key-Locking Inserts, often referred to in industry vernacular as Carbon Steel Keenserts®, are precision-engineered threaded inserts predominantly fabricated from high-grade carbon steel.
Featuring both internal and external threads, these inserts are adept at providing wear-resistant thread interfaces in substrates that are inherently susceptible to thread degradation or are insufficiently robust for the intended mechanical loads. The external threading of these inserts exhibits a larger diameter and pitch compared to the internal threads, ensuring a secure engagement with the parent material.
These components are specifically designed for thread reinforcement and repair applications across a broad spectrum of parent materials. Their key-locking mechanism involves the deployment of keys integrated into the insert body. Upon installation into a pre-tapped hole, these keys are driven outward into the parent material, thereby affording a secure mechanical lock that resists rotational and axial forces. Hence, this feature is pivotal in applications where vibrational loads or cyclic stresses are prevalent.
The versatility of Carbon Steel Key-Locking Inserts makes them beneficial for any sector requiring durable, reliable threaded connections, especially where materials are subject to wear, high stress, or require thread repair and reinforcement.
What Styles, Standards & Sizes Are Available?
Carbon Steel Keenserts®, or Key-Locking Inserts, have different styles in order to cater to a wide range of application requirements and material conditions. The distinct styles are designed to address specific challenges such as load capacity, space constraints, installation requirements, and the physical properties of the base material. Below is a list of all the styles available for these Key-Locking Inserts:
- Thin Wall | RKKA | KNM: These are used when minimal space is available or in applications where less material needs to be removed. They offer a good balance between strength and size. Available off the shelf in Internal Thread 10-24 through 1/2-20 and Metric M5-M12. Often referred to by their original Fairchild part numbers: RKKA
- Heavy Duty | RKK | KNHM: Designed for higher strength and durability, these are suitable for applications subject to high stress or where a stronger thread is required. Available off the shelf in Internal Thread 8-32 through 1-1/2, and Metric M4-M24. Often referred to by their original Fairchild part numbers: RKK
- Extra Heavy Duty | KNHXH: These inserts are used in extremely demanding applications where very high pull-out and torque resistance is needed. Available off the shelf in Internal Thread 6-32 through 1-12. No standard Metric option available. Often referred to by their original Fairchild part numbers: KNHXH
- Solid | KNJ: Unlike other types have both internal and external thread, solid inserts have only external thread. Once installed, they can be drilled and tapped as required. These solid inserts can be used to relocate misplaced holes, customize the internal threads, or plug existing holes. They are extremely durable but might require more installation space. Available off the shelf in External Thread 3/8-16 through 1-1/4 and Metric M8-M32. Often referred to by their original Fairchild part numbers: KNJ.
Commonly available in diameters from 6-32 through 1-1/2, Carbon Steel Key-Locking Inserts can be used in a wide range of applications from small electronics to heavy machinery. The thread pitch varies accordingly, with finer pitches for delicate applications and coarser pitches for heavy-duty applications.
Carbon Steel Key-locking inserts are generally offered as commercial parts, and don’t have a Mil-Spec equivalent. They come standard with a phosphate finish.
*Note – Carbon Steel Key-locking Inserts do not come with a Self-Locking option, which is a standard option with Stainless Steel Keenserts®.
The Carbon Steel Difference!
How do Carbon Steel Key-Locking Inserts stack up against other materials? Here’s the breakdown:
- Stainless Steel: Stainless Steel Keenserts® are known for their corrosion resistance, especially in marine and chemical environments. However, Carbon Steel Key-Locking Inserts are generally stronger and more wear-resistant, which is beneficial in applications where the primary concern is strength rather than exposure to corrosive elements.
- 4140 Alloy Steel: This is a high-carbon alloy steel that provides excellent wear resistance and strength. While 440 Alloy Steel Keenserts® offer superior hardness, Carbon Steel Key-Locking Inserts typically excel in toughness and are more ductile, making them less likely to crack under high stress.
- A286: A286 is an iron-nickel-chromium stainless steel alloy known for its high strength and corrosion resistance at elevated temperatures. Carbon Steel Key-Locking Inserts may not match the high-temperature performance but are significantly more cost-effective for applications where extreme temperatures are not a concern.
- Nitronic 60: This material provides excellent galling and wear resistance. While it is superior in environments where these factors are critical, Carbon Steel Key-Locking Inserts offer a better balance of strength and cost-efficiency for general-purpose use.
- Inconel: Known for its ability to withstand extreme temperatures and corrosion, Inconel is often used in high-temperature applications. Carbon Steel Key-Locking Inserts, on the other hand, are more widely used in applications where high temperature and corrosion are not as critical but where high strength and lower cost are important.
Hence, Carbon Steel Key-Locking Inserts offer an excellent balance of performance and value, making them a preferred choice for applications where the benefits of higher-cost, specialized materials are not required. They stand out for their strength, toughness, and cost-effectiveness, providing a reliable and affordable solution for thread reinforcement and repair.
Carbon Steel Key-Locking Inserts at MF Supply!
MF Supply is a WBE/WOSB certified business, and a leading supplier of Carbon Steel Key-locking Inserts (AKA Keenserts®) for manufacturers, government and industry. At MF Supply, we understand the dynamic needs of the industry, including the balance of price, quality, availability and certification paperwork. Ready to see how we can help you make a difference?
Visit our website or browse through the links provided below to discover the perfect Carbon Steel Key-Locking Inserts for your next project!
Inch Carbon Steel Key-locking Inserts:
- Miniature & Thin Wall Styles Series
- Heavy Duty & Thick Wall Style Series
- Extra Heavy Duty Style Series
- Solid Style Series
Metric Carbon Steel Key-locking Inserts:
Note – Installation requires a drill bit, a standard tap, an installation tool, and a hammer. Feel free to ask us about Keensert® Kits available for many Carbon Steel sizes. Kits include a minimum of 2 inserts, a drill bit, a tap and an installation tool.
Do you still have questions or would like to speak with a representative? Reach out to us, and our MF Supply team of sourcing experts will help you find what you’re looking for. “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.
Six Reasons To Buy From MF Supply
- Creatively Solve Problems – We are sourcing experts and specialize in hard to find parts. We offer custom manufacturing and reworking solutions at competitive pricing, reducing long deliveries.
- Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
- 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.
- 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, with an expertise in inserts, military fasteners and stainless steel hardware. 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.
Inch & Metric Nitronic Keenserts® Now Available at www.mfsupply.com!
Posted: November 15, 2023 Filed under: Brand equivalents, Fasteners, Inch and Mil-Spec Keensert, keensert, key-locking inserts, Metric Keensert, Nitronic 60 Keenserts, Threaded Bushing, Threaded Fasteners | Tags: Fasteners, inch keenserts, Inserts, inserts for manufacturers, Keenserts, manufacturing, Mechanical Fasteners, metric keenserts, Mil-spec fasteners, mil-spec keenserts, Nitronic 60, Nitronic 60 Keensesrts, Nitronic Keenserts, threaded bushing, threaded fastener Leave a commentIn the bustling world of manufacturing and engineering, where every component counts and the margin for error is slim, MF Supply recognizes the intricacy involved in sourcing materials that offer both superior performance and extended durability. This is where our friends, the Key-locking Inserts (AKA Keenserts®) become the stars of the show. Today, we’re turning the spotlight on an insert that’s been making waves in the industry: the Nitronic 60 Key-locking Insert!
If you’re on the quest for Key-locking Inserts that promise to elevate the integrity of your projects, you’re in the right place. Nitronic 60 key-locking Inserts are not just components; they’re your peace of mind molded into high-performance alloy.
Why Nitronic 60 Key-locking Inserts? The Vanguard of Resilience

Picture a material that laughs in the face of wear, shrugs off corrosion, and doesn’t flinch under high torque. That’s Nitronic 60 for you — an alloy steel that’s as tough as they come. Crafted from this robust alloy, Nitronic Key-locking Inserts boast unparalleled wear and galling resistance. For those of you constantly battling the wear and tear that comes with mechanical demands, these threaded inserts are your knights in shining armor. Think of them as the silent guardians against the everyday wear-and-tear that can compromise your work.
The Rust Doesn’t Sleep, But You Can
Corrosion is the arch-nemesis of metal, lurking and waiting to undermine your structures. But with Nitronic 60’s exceptional corrosion resistance, rest easy knowing that your components are as steadfast as your ambition. Whether it’s the salty bath of marine environments or the demanding conditions of chemical processing, they’ve got you covered.
Strength That Speaks Volumes
Nitronic 60 Key-locking Inserts don’t just resist wear; they embrace strength. High stress, high torque — bring it on! The formidable might of Nitronic 60 makes these Key-locking Inserts the backbone for applications that can’t afford to falter, from the aerospace zeniths to the depths of automotive innovation.
The Nitronic 60 Difference
We hear you asking, “But how do they stack up against other materials?” Here’s the deal:
Nitronic 60, as a material, is a high-performance stainless steel alloy known for its excellent strength and resistance to wear and galling. This versatile alloy provides exceptional resistance to high temperature oxidation, crevice corrosion and general corrosion, making it well suited to marine and chemical applications. Key-locking inserts made from Nitronic 60 are used in various applications where high strength and corrosion resistance are a must.
- Carbon Steel Inserts: Compared to standard steel, Nitronic 60 offers superior resistance to corrosion and galling.
- Stainless Steel Inserts: Among stainless steels, Nitronic 60 typically outperforms varieties such as 304 or 316 in wear resistance.
- Inconel Inserts: Inconel excels in high-temperature applications but comes at a higher cost and greater machining difficulty than Nitronic 60.
- 4140 Alloy Inserts: 4140 Alloy provides greater tensile strength and enhanced performance at high temperatures, although it falls short in corrosion resistance and often necessitates protective coatings. Nitronic 60 is better suited for applications involving friction at moderate temperatures.
- A286 Inserts: A286 excels in high-temperature applications, maintaining higher strength at elevated temperatures, though it’s tougher to machine and more expensive than Nitronic 60.
A Spectrum of Possibilities
We’re not about “one-size-fits-all” because we know your engineering needs are as unique as your blueprints. That’s why we offer Key-locking Inserts in inch, mil-spec and metric sizes that are tailored to the scope and scale of your vision — common internal diameters include #2-56 through 1 1/2-6 for inch & mil-spec sizes, and M2 through M24 for metric sizes. And with varying lengths at your disposal, the only limit is the application and your imagination. Materials
Compliance with stringent industry standards is not just a promise; it’s our practice. Our inserts meet or exceed critical aerospace and military specifications, ensuring that they deliver in applications where there is no room for error. Standards available include MS51830, MS51831, MS51832, NAS1394 and NAS1395. Series available include Miniature KNC, Thin Wall KN & KNM, heavy-duty KNH & KNHM, and extra heavy-duty series KNHXH.
Whether you’re in aerospace, automotive, defense, or any field that demands unyielding materials, these inserts are ready to serve. They’re the go-to for applications that require repeated assembly and disassembly, ensuring longevity and reliability every step of the way.
Discover More, Achieve More
MF Supply is a WBE/WOSB certified business, and a trusted supplier of Nitronic 60 Key-locking Inserts (AKA Keenserts®) for manufacturers, government and industry. Eager to delve deeper into the world of Nitronic 60 Key-locking Inserts? Visit our website, where innovation is just a click away, and join the ranks of manufacturers and engineers who don’t just build, but inspire.
With Nitronic 60 Key-locking Inserts, it’s not just about holding things together; it’s about unlocking possibilities. Discover the sizes, standards, and the success that our inserts can enable.
Inch & Mil-Spec Nitronic 60 Key-locking Inserts
- Miniature & Thin Wall – KN, KNL, KNC & KNCL Series
- Heavy Duty – KNH & KNHL Series
- Extra Heavy Duty – KNHXH & KNHXHL Series
Metric Nitronic 60 Key-locking Inserts
Do you still have questions or would like to speak with a representative? 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.
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 and specialize in hard to find parts. We offer custom manufacturing and reworking solutions at competitive pricing, 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.




