Buyer’s Guide to One and done Keensert® Ordering

keenserts installation

Your 5 point checklist to getting it right the first time

What is a Keensert®?

Keenserts® are solid bushing style inserts that are threaded on both the inside and the outside, and have wedges or “keys” attached at the top. They are generically called key-locking inserts, and 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.

Although the name Keensert® is often used generically (like Band-Aid® or Kleenex®), Keensert®  is the registered trademark of Huck Patents (its close cousin, the Keysert® is a registered trademark of Alcoa Fastening Systems.).

How do I simplify my buying process to get what I need to complete the job on time and right?

We are all familiar with that classic adage “Measure twice, cut once”.  Nowhere is this more relevant than in the world of manufacturing.  If you are involved in procurement, you are challenged with making sure you have the right parts available at the best price  so your factory can deliver on time and on budget.   Missing tools, incorrect paperwork and long delivery times can cause major headaches and negatively impact service levels.

Our goal is to help you make the Keensert buying process easier, which in turn will eliminate stress, reduce multiple shipments and potentially increase your profits.  The result?  Happier customers (and finance departments too)!  So here it goes…..

  1. Make sure to order the correct part.

Due to the price, availability and high minimum order requirements of Huck or Alcoa branded Keensert® parts,  using functional equivalents including Mil-Spec parts has become a common practice.   Request that your supplier makes reference to the part number listed on your bill of materials on their sales order and packing slip. This will ensure you are getting the functional equivalent that you need.

If you are not ordering by part number, make sure to call out both the internal and external thread including the thread class (UNC, UNF, UNJ), the material and plating, and any special finish you need.

  1. Place blanket orders for your total project needs to get the best price and ensure availability of parts when you need them.

Most standard size non-locking miniature and thin wall / light weight Keenserts® are readily available off the shelf in 303 stainless steel or carbon steel.  However, some locking style, nonstandard diameters, 4140 alloy, A286, heavy duty, extra heavy duty, solid and floating style Keenserts® are available only by special order and usually involve a long lead time.  Make sure to get current price and delivery and order parts as early as possible.  Many suppliers allow you to order now and ship later, which can prevent delivery delays.

If you have an ongoing project, calculate your total needs and place your order with staggered delivery dates.  This will get you the best available pricing and ensure you have the parts when you need them.  Remember, price breaks can start at as few as 100 pieces.

  1. Order (the correct) installation tools with Keenserts® for maximum efficiency.

Whereas most common size and material installation tools are readily available off the shelf, less popular sizes and materials might involve a lead time.  Parent materials harder than RC30 or Anondized Aluminum may require that the tapped holes be broached for the keys, which requires the use of broach blades.


broaching tool

In addition, there are manual and power installation tools to choose from, so consult with your supplier on which tool is correct for your job.  Note:  manual tools work well for jobs up to 999 Keenserts®.  For installations of 1000 Keenserts® or more, a pneumatic tool is recommended.

  1. Order the Correct drills and taps for proper installation

Although Keenserts® are installed with standard drills and taps (plus the installation tool and a hammer) each part has a specific hole/tap dimensional recommendation. The drills used are often oversized for the external thread size.  When purchasing key-locking inserts, check with your production department to make sure you have everything you need for proper installation. Note: Drill is oversize see charts for proper dimensions.

Kits are handy to have in the shop and are available for most common sizes.  These kits include 2+ Keenserts®, the associated drill, tap and manual installation tool along with instructions for correct installation.

  1. Request COC, MTRs, DFAR and all required paperwork on your RFQ and PO.

Since using functional equivalents including Mil-Spec parts is a common practice, make sure you have dotted your i’s and crossed your t’s when it comes to paperwork.  Ask your supplier to reference the branded part number listed on your bill of materials on their COC and packing slip to make sure you are getting the functional equivalent that you need.  In most cases, a Certificate of Conformance or a COC referencing the part number you ordered is all the paperwork you need.  Certain aerospace customers need a complete Manufacturer’s Test Report (MTR) package including DFAR statement and passivation certs with full lot traceability.  This might involve a fee, so include it in your RFQ.  Whatever your requirement, include it on your Purchase Order to make sure you have what you need to satisfy your customer’s needs.

In summary, follow this handy 5 point guide when ordering Keenserts® and watch your costs decrease and your service levels soar!

For more information about MF Supply contact:

Robin Lieberman, President

Four things you need to know when buying Captive Panel Screws

Captive Panel Screws New Jersey

Captive Panel screws are a type of screw that remains attached to the parent material when separated from the mating part. These special screws are used to fasten PC boards, cabinets, drawers, furniture, equipment panels and more. But, what exactly are they and what should you know before getting a quote or buying them? We’d like to help you out with this four-point buyer’s guide.

  1. What are Captive Panel Screws?

Captive Panel Screws provide simple and secure mounting of hardware to panels and other assemblies. These special fasteners reduce the risk of lost parts and damage from loose screws falling into moving parts. They allow for speedy repeated assembly and disassembly operations. Used along with retainers, washers, nuts or springs, these screws come in a variety of sizes, styles and materials.

  1. What information should I provide to get an accurate quote?

The easiest way to order is by manufacturer part number. The most popular manufacturers of Captive Panel Screws are: Amatom, Concord, Globe, Grainger, H.H. Smith, Lyn-tron, Misumi, McMaster Carr, MSC Industrial, RAF and Unicorp. If you don’t have a part number, you’ll need to specify the style and there are many! Styles are generally represented by a number (1 through 6) or a letter (A, B, C, D, E). Other than style, you’ll need the head style, drive type, shank length, thread, point type, material and plating. For example, a popular Captive Panel Screw is a 1/4 -20 x 1” Long Hex Socket Drive Captive Panel Screw in 18-8 stainless steel.

  1. What sizes and materials are available off the shelf?

Depending on the manufacturer and style, Captive Panel Screws are available off the shelf in inch sizes starting as small as 4-40 thread up to 3/8-16 in both coarse and fine thread. Metric Captive Panel screws are available from M3 through M6 and are most common in coarse thread.

Common materials are brass, steel and 18-8 stainless steel.

Threads, head sizes, shank sizes, screw lengths and screw tips are related to the style of the Captive Panel Screws and all sizes may not be available in all materials and styles.

As always, special lengths, sizes and materials are available but may involve a lead time – just ask!

  1. Are there other factors to consider?

YES! One surefire way to save money and shorten delivery time is to cross the OEM brand part on your bill of materials to a functional equivalent.

Finally, although Captive Panel Screws can be installed easily with thumb pressure, and many times don’t require specialized equipment for installation, methods to attach the screw to the parent material include using split washers, springs, nuts and retainers.  Make sure you order the proper mating parts to complete your Captive Panel Screw assembly.

For more detailed information about Captive Panel Fasteners, to request a line card or to send an RFQ, visit our website. And if you don’t see what you need listed, as always, ask us. “Finding the right screw for you” is our tag line after all!

Contact me at with your questions, comments or helpful hints!


Buyer’s Guide to Ordering Custom or Reworked Parts per Print

Custom made fasteners

4 Things you need to know

when buying

Custom Made & Special Fasteners

Precision manufacturers and OEMs regularly use custom or designed and engineered-in fasteners and machined parts in the manufacturing process. These “per print” parts may be for a prototype of a new product, a replacement of an existing part, or for a large-scale production run. No matter the reason, this guide will help simplify your process for procuring quotes and ordering custom parts.

1) What are custom parts “per print”?

Fasteners and components that are non-standard and not commercially available and must be manufactured to a print or a drawing are considered “per print” fasteners. Although you’ll find thousands of variations of fasteners, the most common reasons to custom make a part include: a need for an unusual diameter or in-between length, an uncommon material or plating, or a special head size or drive type. For example, an M6 x 1.0 x 37 metric socket cap in A286 material would need to be custom made since the length and the material are nonstandard.

2) What information should I provide to get an accurate quote?
For the most accurate quotes, provide the following six pieces of information:

  • A print with dimensional and tolerance requirements
  • Details of the material and plating specification
  • Quantity levels including EAU for possible price breaks
  • Paperwork needs, which might include: Certificate of conformance, material test report, ROHS or DFAR requirements, domestic or country of origin, first article or PPAP
  • Delivery needs, including desired deliver by date
  • A price target if you have one

If you have any special labeling or bagging requirements, include that information on your RFQ as well.

3) What are reworked parts and how are they different from per print parts?
Reworking parts usually involves taking a commercially available screw and performing a secondary service, that is, removing or adding something to the screw. Common secondary services include, broaching a drive socket into a screw product, slotting a fastener head, adding grooves, special threads, trimming, cutting, drilling or captivating a fastener. Adding special platings, heat treatments, patches, pellets and other locking elements are also considered secondary processes. The majority of “per print” parts involve a secondary service, hence they are manufactured in several steps usually involving several different factories.

4) Are there other factors to consider when selecting a vendor for per print and reworked parts?
We suggest you work with a vendor experienced with established ISO certified factories that specialize in the specific category of part you need. An experienced vendor can help identify the factory best suited for your requirements, and they can compare quotes from their top sources domestically and abroad. The benefits to working with an experienced fastener supplier include:
• One point of contact
• One bill to pay
• Quality control of multiple factories and secondary services
• Stock and release options

And many other benefits that mean you get the right part fast and accurately.

For more detailed information about custom made parts, visit our website. And if you don’t see what you need listed, as always, ask us. “Finding the right screw for you” is our tag line after all!

For more than 40 years, MF Supply has helped American manufacturers streamline operations, saving them time and money with our sourcing expertise and unique supply chain strategies. We are a WBE/WOSB certified stocking distributor of fasteners and electronic components.

We work with the best-established factories in the United States and DFARS-certified countries, and stock a huge inventory including all major brands and equivalents. MF Supply provides solutions including: same-day drop ship direct from the factory; custom sizes, materials and plating options; and DFARS parts with full paperwork and Certificates of Conformance.

We creatively solve common problems including hard-to-find parts and long lead times. Our sourcing and reworking expertise includes fast turnaround for modification of existing parts, hard to find standards and specials, special threads, non-standard diameters and lengths, exotic materials, special platings and short runs. We provide functional equivalents to expensive brand name fasteners and help our customers save money while reducing lead times.

MF Supply is a leading supplier of custom parts per-print specializing in the following categories of specials, custom, and reworked hardware: socket products, aero-space and mil-spec parts, tamperproof, electronic, spacers and standoffs, washers, nuts and thread-forming fasteners.

Follow our blog at

To request a Custom Quote, email yout print to




Keensert® Buyer’s Guide

Keensert® Buyer’s Guide

5 Things You Need to Know

If you are a precision manufacturer working in high-torque and high-temperature situations, you might already be familiar with Keensert® key-locking inserts.  Common uses include thread repair applications or to provide thread durability in situations such as aerospace assemblies, electronic equipment and suspension units.

But, what exactly are they and what should you know before buying them? We’d like to help you out with this quick buyer’s guide.

  1. What is a Keensert®?

A Keensert® 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. They are generically called key-locking inserts, and are used to distribute loads and repair or strengthen threads against failures due to stripping, seizing or corrosion.

Although the name Keensert® is often used generically (like Band-Aid® or Kleenex®), Keensert®  is the registered trademark of Huck Patents (its close cousin, the Keysert® is a registered trademark of Alcoa Fastening Systems.).

Before you shop, check to see if the bill of materials specifically calls out Huck or Alcoa brand as the Keensert®  manufacturer. If no specific manufacturer’s name is listed, then you can typically use an alternative like Rock Solid brand, a generic equivalent or cross to a MIL-SPEC part.  This becomes important due to price and availability of the brand name parts.

  1. What materials and sizes are available?

Keenserts are available off the shelf in 303 stainless steel or carbon steel. Standard diameters are: American #6-32 to 1 ½” and Metric  M4 to M24. Other diameters (starting at 2-56 and M2) and materials (including 316 stainless steel, and alloys 4140 and A286) are available for special order and usually involve a lead time.

  1. What information do I need for ordering?

To order, you’ll need the manufacturer’s part number or the internal and external thread and material. Alternatively, key-locking inserts often show up under their MIL-SPEC numbers, which can often be crossed to commercial equivalents. Common MIL-SPEC numbers include: MS51830, MS51831, MS51832, NAS1394, NAS1395, NA0146, NA0147, NA0148, NA0149, NA150, and NA0151.

  1. Do I need to buy special installation tools?

When purchasing key-locking inserts, check with your production department to make sure you have the tools you need to properly install inserts. You can buy kits that include a tap, drill, and installation tool.

  1. What level of certification is required?

Generally, a Certificate of Conformance or a COC is sufficient. Full certification with material certs and test reports are often available for a fee.

In summary, in order to have the most efficient Keensert shopping/buying experience, be prepared with the following information before you shop:  Do you need the Alcoa or Huck brand product or can you use a generic or MIL-SPEC alternative?  Make sure to have the manufacturer’s part number, MIL-SPEC part number or the internal/external thread and material.  Do you need an installation tool? Finally, check to see if you require a standard COC or full certs.

For more information about MF Supply contact:

Robin Lieberman, President


Newsletter – January / February 2016


Volume 18
February 12, 2016
January / February News
Greetings and Happy February!  We started 2016 fast out of the gate and are ramping up for a strong Q1, despite a PMI index of 48.2%, reports of contraction in the manufacturing sector and the volatility that sometimes occurs during election years.  I hope you are experiencing growth!
Today, I am continuing our discussion on thought leadership within the American Manufacturing community. Additionally, I am glad to get back to our “What the Heck Is that” roots and put the spotlight on one of our best-selling products, the Socket Head Cap Screw.
Since graduating on October 27, I have been introduced to many amazing resources.  One exciting development I wanted to share with you is that MF Supply was selected as a case study class for Rutgers Business School. What does that mean, you ask?  Well, between now and April 20th, a group of smart and creative Rutgers MBA candidates are analyzing MF Supply and our marketplace. They will use BIG DATA and other tools, and present recommendations including an ROI on where we should focus our energies to grow. One of their initial thoughts was that MF Supply should be targeting companies with Set-Aside needs or Diverse buying initiatives.  If you hadn’t heard, MF Supply is a WBE and WOSB certified business, which means if your customer has Set Aside needs, we should be talking!  I am so excited for this project and am thankful to the SBA for connecting me to Rutgers and other resources.
If you are curious to know more about the SBA-EL program (in NJ or your state), or think you or someone you know might benefit from participating, please check out these two articles about the program inNJBIZ and American Entrepreneurship Today to find out more. To apply, please email and tell him I sent you!

Socket Head Cap Screws or socket caps, which are sometimes referred to by their trademarked name “Allen” screws, have become the standard among high strength fasteners needed to withstand the faster speeds and higher pressure of today’s machines, instruments and assemblies.  They are externally threaded, with a cylindrical head with a flat chamfered top, and a hexagonal recess for internal wrenching.
Who uses Socket Head Cap Screws?
Because of their cylindrical shaped heads and internal wrenching installation method, socket cap screws need less space than alternative fasteners.  This makes socket caps ideal for precision assembly work with close tolerances and applications that need a well tooled appearance.
Common uses include machine parts, die fixtures and assemblies.
Why use a Socket Cap vs a Hex Head Cap Screw?  
We don’t want to play favorites, but here are a few advantages of using socket caps:
Size matters– The smaller socket head enables driving where there is not sufficient space for wrenches or sockets. In addition, Socket caps are available off the shelf starting as small as 0-80 diameter and are commonly available to diameter 1-1/2-6.  Hex Head Cap screws start at 1/4-20 diameter.
Strength – Alloy Steel Socket Caps, though not measured in grades, provide greater tensile strength than equivalent size Grade 5 or Grade 8 steel Hex Head Cap screws.  i.e. 1/4-20 Socket cap=180k psi min, 1/4-20 Hex Head Grade 5 =120k psi min,  1/4-20 Hex Head Grade 8 =150k psi min.
Torque  – The 6 flat surfaces within the recess allow for high torquing without damaging the head,  and with no side clearance restrictions or additional wrench space.
Thread fit- Socket products generally have a 3A thread fit.  3A threads have restrictive tolerances often used where safety is a critical design consideration. Hex Head Cap Screws are generally class 2A.  2A threads offer a combination of performance, economy, and convenience. Nearly 90% of all commercial and industrial fasteners have a 2A fit.
Economy –  Socket Cap heads are smaller, hence, the size of the component parts can be reduced, reducing material costs.  Smaller parts cost less to drill and tap, take less energy to drive, and weigh less than alternatives.
What options are available?
The most common variables are the head style, diameter and thread, length, material and plating or finish.  Socket caps can also be captivated, vented, patched or pelleted.  Below are some of the most common options:
There are 4 main available head styles, and each serves a slightly different purpose. All commercial Socket Caps conform to ASME B18.3.
Standard Head  – the standard in Socket Head Cap Screws (ASTM A574, F835, DIN912)
Low Head – Use in parts too thin for standard height heads and where clearance is limited (DIN7984)
Flat Head  – Countersunk heads at 82 degrees provide maximum flushness and side wall contact  (ASTM F835, F879, DIN7991)
Button Head – For use in materials too thin to countersink (ASTM F835, F879, DIN7380)
The most common and readily available drive style is a hexagonal socket drive, however, Socket Caps may also be available in security pin-in-hex, pin-in-torx, or six-lobe torx versions in certain sizes and materials.
Are there other factors to consider?
Of course!  “Steel” Socket Caps off the shelf are alloy steel black oxide through heat treatment and come oiled. If you need greater corrosion resistance or a different look than black, consider stainless steel or zinc plating.
If you are considering zinc plated Socket Caps, proceed with caution! Because of their tight tolerances and 3A fit, zinc plating a Socket Cap will often change the thread fit to a commercial nut fit.  If you need a 3A fit, you must specify that on your purchase order so the factory can meet your thread fit needs when creating and plating your screws.
Beyond color and plating, there are always other factors to consider, such as: domestic or import, commercial or mil-spec, with or without sprinkles :). And remember, Socket Head Cap Screws can also show up under their most popular domestic brand names (Holo-krome) and mil-spec number (MS16995, MS16996, NAS1351 and NAS1352).    If you have any questions, please reach out and ask!
Socket Head Cap Screws available at MF Supply
Here at MF Supply, we offer:
  • The full range of commercial and mil-spec parts, including parts that are DFARS and ROHS compliant.
  • Brand names (Holo-krome), generic equivalents, domestic and import.
  • Custom made parts per print in non-standard and exotic materials and finishes.
  • Inch and Metric sizes.
  • Stainless steel in 18-8, 316, A286, A2 and A4 (ASTM F837, F879).
For more detailed information on Socket Head Cap Screws, visit us at
Did you ever get an invitation that piqued your interest, and show up at an event wondering if it would be worth your time?  On January 27, I said yes to an NJMEP invitation to a Manufacturers Roundtable, hosted by Bergen Community College. I am so glad I went!
Assemblyman Gary Schaer, along with 30 manufacturers, educators and other advocates discussed ways we can support manufacturing in NJ.  Many connections were made, and last week, a group of 10 of the students from Bergen’s current CNC training class visited MF Supply to learn more about the Supply chain. They were a bright, motivated and very impressive group of students.  If you are hiring, great!  I’d love to connect you to the team at Bergen Community College.
And get yourself on the NJMEP (or if you are outside of NJ, contact your state’s MEP) email list to find out about relevant events and programs that just might be a difference maker for your business.
On November 1, 2015  we were officially welcomed into the DPA Industrial family.  What does this mean for our customers?  We can now help you with more product categories and pass along fabulous savings on many more items including:
  • Industrial
  • Safety Equipment & Clothing
  • Packaging
  • Janitorial/Sanitorial
Please contact me to set up a meeting to see if we can help save you time and money by becoming a single source for more of your industrial needs.
Since our core values include striving for achievement, self improvement and growth, we are exploring Lean certification. Is being Lean one of your initiatives? Check out this inspirational video about how Lean processes lead to immediate improvements in a NYC foodbank.   Enjoy the video by clicking here!
Robin Lieberman
P.S. We are closed on February 15 in observance of President’s Day. Wishing you and yours a happy and healthy long weekend and Valentine’s Day from the entire team here at MF Supply.

What the heck is that fastener? The year in review – 2014.


Volume 12  

December 17, 2014

What the heck is that fastener?

Welcome to 2014’s final edition of our “What the heck is that” newsletter and blog where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products.

December is a great time to reflect on all we have learned so far this year and get educated on topics that impact manufacturers. So keep reading for a chock-full of fastening info!

Take a read down memory lane as we review our previous blogs and reacquaint you with some of our most popular topics.  Visit our blog directly at  for full articles and information.

Cage Nut

A Cage Nut contains a free floating threaded square nut retained within a spring steel cage. The spring steel cage has two Mounting legs or wings that, when pressed together, lock the fastener in place within a rack hole.

Cage Nuts are commonly used to mount lighting systems, electrical equipment or instruments onto rail racks.

Mil-spec DFARS

Mil-spec is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment and supplies.   The government maintains a list of qualified factories [QSLM] and suppliers [QSLD] that pass the highest quality control standards for screw attributes, including: dimensions, tensile strength, hardness, threads and drive type, just to name a few.

DFARS pertains to fasteners made from “specialty metals” including: stainless steel, high alloy steel like Grade-BD, or Grade 5 Chromium steel . For a fastener to be DFAR Compliant, the metal used to make the fastener must be melted and manufactured in the United States or a qualifying country. To keep up to date with DFARs requirements, visit section 252.225.

Wire Insert

Wire inserts are precision-formed continuous helical wire coils that provide permanent, wear-resistant threads which exceed the strength of the parent material.

Wire inserts are used for 3 main reasons: 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.

Sometimes referred to by the brand name “Heli-coil”, wire inserts can be locking or nonlocking, tanged or tangless.

Standoffs and Spacers

Often classified as Electronic Hardware, or Panel Hardware, Standoffs are hex or round shaped fasteners which have a body and two threaded ends. Spacers are similar to Standoffs, however, Spacers are unthreaded with an inside clearance hole.

Both are commonly used to mechanically support, connect and position components within assemblies.

Standoffs and spacers are often ordered by their brand name, including: RAF, Amatom, Concord. Globe, HH Smith and Keystone.

Precision Shoulder Screws

Precision Shoulder Screws are tight tolerance screws which are comprised of 3 main parts: the head, the shoulder and the thread.

Used to locate or hold parts together within a precision assembly or a fixture, when installed, the unthreaded shoulder acts as a shaft for rotating items such as bearings and bushings, precision spacing, machinery support, and motion guiding.

Common brands are PIC and WM Berg, RAF, Mcmaster-Carr and MSC.\

Dowel Pins

Dowel Pins are solid, headless cylindrical shaped straight metal pins with a centerless ground finish.

Often used as a hinge, shaft or pivot to locate or hold parts together within a precision assembly or a fixture, Dowel pins can be Standard, Oversized or Undersized.

Common brands are Holo-krome and PIC and WM Berg.

Retaining Rings

Shaped like an open ring and made of metal, Retaining Rings can be coiled from wire, stamped or laser cut.

Retaining Rings work together with a bore or a shaft by snapping into a groove or being pushed into place to create a high strength shoulder to retain parts.

Common brands are Rotor-Clip and Waldes,Truarc.

Keensert® Key-locking insert

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.

Generally, Key-locking inserts are used to distribute loads and strengthen or repair 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.

 Set screws

Set screws are externally threaded fasteners with a drive (commonly hex socket) on one end and one of 7 (yes 7!) point styles on the other.

Designed to fasten one object inside another, set screws are commonly used within assemblies with rotating items such as pulleys or wheels where a component is locked onto a shaft.

And that’s all she wrote……

You might have noticed an important theme here.  Many fasteners are used as part of an assembly that involves a shaft with moving parts.  And in the fastener world, we’ve got options.  Lots and lots of options.

If there are fasteners that you would like us to profile, please be in touch.  And if you need help finding the right screw for you and your application, you know where to find us.  See you in 2015!

Warm Regards,


The Screw Lady

Cage Nut

Cage Nut

Cage Nuts!