Get the Job Done with a Pneumatic Power Tool

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

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

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

What is a pneumatic power tool? 

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

How do I use a pneumatic power tool? 

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

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

The Rock Solid Hydro-Pneumatic Key-locking Insert Installation Tool (KEENTOOLPNEUMATIC-RS) is bound to save you valuable time and energy that could be put to better use in the installation of many more key locking inserts! 

What are you waiting for? Request a quote today! 

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

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

Keensert Installation Tool Kit

We offer the pneumatic power tool you need to quickly assemble your key locking inserts! Check them out here.

Learn More About MF Supply

MF Supply is your go-to for all of your hardware and safety needs! Continue to browse our website and contact us today if you would like to learn more!

Floating Inserts Now Available!

Floating Key-locking Inserts are often used to help compensate for uneven surfaces which need alignment, and where expansion and contraction are an issue. We offer the KNK series in both locking and non-locking styles from size 2-56 through 1/2-13 in A286, 300 Series Stainless Steel and 4140 Alloy Steel.

Floating Keenserts Available At MF Supply

Keensert Functional Equivalent Case Study

We had a customer who was bidding on a job for subassembly for a Defense Department manufacturer. Their bill of materials called for a floating insert in 8286 steel with an OEM part number: KNKDL428JT.

This part is an Alcoa part that would not have been delivered for over 29 weeks – that’s more than half of a year! Not only would these parts take way too long, but they were also very expensive.

Functional Equivalents for Keenserts

So, this customer came to us for a solution. We were able to take their print, cross-reference their BOM, and find the functional equivalents they needed.

  • Note: Supplying us with your print is extremely important so that we can determine the internal and external threats, the material in all of the specifications for this key locking insert.

We went to our manufacturer, who was able to provide this part in five weeks with full certifications and a certificate of conformance certifying that it was a functional equivalent to the KNK part.

Why Choose MF Supply for Functional Equivalents?

By providing the functional equivalent, we were able to shorten the delivery time from 29 weeks down to five weeks. We obtained a cost savings of 59%. Our customer won the job. Their work was completed on time. The job was more profitable due to the cost savings. The manufacturer was able to pass those savings on to the end-user, and the job has been a repeater, and it’s been profitable for everyone involved.

If you find yourself in this situation and you’d like to evaluate if a functional equivalent is available for your application, or if you’d like to explore if you can save time and money while maintaining quality by using functional equivalence, our team is here for you!

Learn More About MF Supply

We specialize in hardware solutions for many industries! If you have any questions about our products, please contact us today and continue to explore our website.

You can also read about other case studies for functional equivalents here:

Keensert Installation Tool Kits

Keenserts are very small but very strong key locking inserts used across many industries, especially in aerospace and precision manufacturing. While Keenserts are easy to install, it is essential to have all of the necessary tools to properly install them.

What Hole Size and Tools do I Need to Install My Keenserts Manually?

This is a common question we receive from manufacturers, so today, we are going to share everything you need to know to install your key locking inserts.

Prior to installing a key locking insert, you have to check with the supplier to make sure you have the proper drill and tap. Each part number has its own combination of drill and tap. This is really important, and it’s based on the outside and inside diameter.

Check out our Keensert Buyer’s Guide, Keensert Cross-Reference Guides, and How to Manually Install Keenserts.

Commercial or Military Key Locking Inserts?

It’s also important to note that each key locking insert has different types of thread depending upon their military or commercial. So, prior to installing the inserts, you need to have the following information…

  • Nose assembly.
  • Drill and tap size for the insert you’re installing.
  • The fastener you’re installing.

Tools For Keensert Installation:

  • Drill
  • Drill Bit
  • Drill or Tap Wrench
  • Tap
  • Countersink Tool
  • Keensert Installation Tool
  • Hammer

What is a Broaching Tool, and When Will I Need One?

A broaching tool is an extra installation tool that is used for very hard parent materials such as A286 or A4140. The purpose of the broach is to create slots for the keys in the parent material when the regular tools won’t cut it.

Hydro-Pneumatic Keensert Installation Tool

If you are installing key locking inserts by the 1,000s, then the pneumatic tool is a better option for installation. Learn more here.

Learn More About Keensert Installation

If you would like to learn more about our key locking inserts or any of our other hardware products, continue to browse our website and contact us today!

Installing Key Locking Inserts with Pneumatic Power Tools

In last week’s blog, we discussed when and how to install key locking inserts manually. If you have a few hundred inserts to install, the manual process is fine. However, if you are installing these Keenserts by the thousands, then you will want to use a pneumatic power tool to speed up the processes.

How to Install Keenserts with a Pneumatic Tool

  • The beginning of the installation process is the same as a manual installation.
  • Drill and Countersink the Material
  • Tap the Material
  • Manually Insert the Key Locking Insert
  • The next step is to use the power tool to simply screw the key into place.

You can see how this process can save you so much valuable time if you are installing the key locking inserts by the thousands!

Keensert Installation Tool Kit

We offer the pneumatic power tool you need to quickly assemble your key locking inserts! Check them out here.

Learn More About MF Supply

MF Supply is your go-to for all of your hardware and safety needs! Continue to browse our website and contact us today if you would like to learn more!

How to Manually Install Key Locking Inserts

What is a Keensert?

A Keensert or key locking insert is a solid bushing style insert that is threaded on both the inside and the outside and has wedges or “keys” attached at the top. These inserts are used to distribute loads and repair or strengthen threads against failures due to stripping, seizing or corrosion. They are commonly used in precision manufacturing and aerospace applications.

Check out our Buyer’s Guide to Keenserts!

What is the Best Way to Install Keenserts?

There are a few methods used to install key locking inserts. Manual installation is best for assemblies that are in the hundreds, but if you are installing a lot of Keenserts, pneumatic installation is the way to go.

Keensert Manual Installation

  1. Drill and Countersink the Material
  2. Tap the Material
  3. Manually Insert the Key Locking Insert
  4. Use the Installation Tool to Drive the Keensert

Here is the full installation clip from the video.

Stay Tuned and Learn More

If you are interested in learning more about our hardware, check out our other blogs and browse our products online. If you would like to learn how to install Keenserts with pneumatic tools, stay tuned for next week’s blog!

Metric Keenserts

What is a Keensert?

A keensert is a small, bushing style insert that is threading on the inside and outside, with external wedges called keys. Keenserts are a piece of hardware used to distribute loads and to strengthen or repair threads against failure due to stripping, seizing, or corrosion. They are often used in high vibration environments such as instrument panels on airplanes.

Metric Keensert Style

Metric keenserts come in a variety of styles, each with many sizes and materials.

  • Miniature Keenserts
  • Thinwall Keenserts
  • Heavy Duty Keenserts
  • Solid Keenserts

Keensert Cross-Reference

Keensert® Cross-Reference – 4140 Alloy, A286, & Mil-Spec
Keensert® Cross-Reference – Stainless Steel

Quantities of Keenserts from MF Supply

We sell our keenserts in orders as small as 5 pieces all the way 2,500 or more. The more you buy, the more you save!

Learn More About Hardware with MF Supply

MF Supply is your one-stop-shop for all of your hardware needs! Contact us today if you have any questions about our keenserts!

Keenserts: Inch and MIL-SPEC Keylocking Inserts

What is a Keensert?

A Keensert is a small bushing style insert that is threaded both inside and out, with wedges or little keys that are attached to the top of the insert. This small piece of hardware is generally used to distribute loads and to strengthen or repair threads against failure due to stripping, seizing, or corrosion.

When is a Keensert Used?

They are used in environments that have a lot of vibration, torque, and even in high-temperature applications. They are also sometimes used in applications where a fastener has to be taken out, replaced, or it has to be reassembled.

What Size and Material Keenserts Does MF Supply Sell?

Our Keenserts come in a variety of sizes and materials; you can view our entire selection on our online store here.

Need to cross your part number to find the right Keensert for your needs? Use our Mil-Spec & Inch Keensert Cross Reference charts!

Why Choose MF Supply for Your Keenserts?

We specialize in the military version of Keenserts, so we carry the MS51830 series, which is an equivalent to the KN and KNC series. These are a high demand Keensert.

They come with full paperwork and traceability. The majority of those our Keensert are stainless steel, but you can get them in a variety of materials and sizes.

Another huge benefit is that we stop-limit our distribution centers around the country so we can drop ship them at a moment’s notice, so there is no delay.

Learn More About Fasteners from MF Supply

If you are looking for a quick and reliable fasteners distributor, MF Supply is a leading supplier of Inch & Mil-Spec keylocking inserts. Contact us today to learn more!

“Heli-coils” vs. “Keenserts”: 3 differences you must know-Part 1 of 2

Today we will compare 2 popular fastener products that are used to repair damaged threads or strengthen a weaker parent material like aluminum: Helical Wire Inserts and Key-locking Inserts.  Both are commonly used in precision manufacturing and aerospace applications.

What are the main uses of these threaded inserts?

Both “Heli-coil” or Helical wire inserts and “Keensert” or Key-locking inserts fall under the “Threaded Insert” category of fasteners. A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They 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 1) to repair damaged threads in parts that would otherwise have to be scrapped; 2) to strengthen threads against failures due to stripping, seizing or corrosion; 3) 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 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.

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

Helical wire inserts

Helical wire inserts come in 2 main styles: tanged and tangless (currently, MF Supply spcializes 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 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.

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.

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

  1. Full ecommerce enabled website with technical manual available 24/7
  2. Same day drop ship from factory for thousands of items.
  3. Functional Equivalentsto expensive brand name fasteners save money and reduce long lead times.
  4. Creatively solve problems including hard to find parts and long lead times
  5. WBE/WOSB Woman Owned Certified Small Business.
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Brand Equivalent Case Study: Achieving faster delivery & lower costs using functional equivalents

October 9, 2018

Here at MF Supply we spend a lot of time sourcing hard to find, back-ordered or out of stock OEM hardware brands for our customers. Much like brand-name pharmaceuticals such as Tylenol and Advil are available generically (as acetaminophen and ibuprofen), some brand name fasteners are also available as “generics,” “crosses,” “alternatives” or “functional equivalents.”  In the world of fasteners, a functional equivalent fastener is a part that is the same as the brand-name product in form, fit and function, including material and plating specifications.  Using equivalents and alternatives to OEM brand names can be a smart way to reduce long lead times and/or cut expenses.

Check out this Case Study where an OEM brand was substituted with a functional equivalent, reducing costs by 59% and shaving lead time by over 20 weeks.  This time and money savings gave the manufacturer an advantage over their competition, which helped them win the job.

Smart Manufacturers use equivalents to shorten delivery times and win business


A Tier 3 aerospace manufacturer of subassemblies is bidding on a job for a large international Aircraft OEM where the bill of materials calls for 172 pieces of a 1/4-28 x 1/2-20 Floating Key-Locking Insert in A286 stainless steel with a Fairchild/Alcoa Keensert® part number KNKDL428JT.  As the part is in nonstock status at Alcoa, the delivery time is 28-29 weeks (yes that is half of one year which can be standard for aerospace related and mil-spec parts).  Here is the dilemma – based on this delivery schedule, the manufacturer cannot meet their prospective client’s two month delivery requirement.


MF Supply gets a print of the part and is able to cross it to an exact functional equivalent for an alternative brand we distribute.  Our factory can manufacturer and deliver the part in 4-5 weeks at 1/2 the cost of the OEM brand fastener.  The alternative parts will be manufactured with full lot traceability and manufacturer’s test reports, a certificate of conformance and a DFARS statement.  The client (Aircraft OEM) approves the substitution and awards the manufacturer the business based on their ability to make the 2 month delivery requirement.  A Purchase Order for the Floating Key-Locking Insert is issued to MF Supply.  As promised, within 5 weeks, the complete 172 inserts, with full paperwork, are delivered to the manufacturer.  The subassemblies are produced and delivered to the end client on time and underbudget.


-MF Supply functional equivalent fasteners shorten delivery time from 28-29 weeks to 5 weeks.


-KNKDL428JT price = $200 each.  Total cost $34,400.
-MF equivalent price = $82.00 each. Total cost $14,104.


-Cost savings of $20,296 or 59% (not a typo!).
– Tier 3 aerospace manufacturer wins bid and is awarded job.
-Work is completed on time.
-Job is more profitable due to cost savings realized on inserts.
-Job has been a repeater and a money maker for Tier 3 aerospace manufacturer.

In summary, if your bill of materials calls for an OEM brand fastener or component, find out if you must have the brand name product.  In cases where a generic or equivalent alternative part will work, there might be an opportunity to save money and shorten delivery time.

How can I determine if I must use the brand name or if I can cross to a generic part?

Before you shop, check the bill of materials to see if it specifically calls out a particular brand name along with the part number. If no specific manufacturer’s name is listed, then you can typically use a  generic alternative or equivalent product?.  For more complete info, check out our July 27 blog for your 4 point checklist on determining if functional equivalents will work for your business.

For more information about MF Supply contact:

Robin Lieberman, President