Case Study: Avoiding a 26-Week Delay with Stocked DFARS Screws
Posted: December 16, 2025 Filed under: DFARS, Domestic Fasteners, keensert, key-locking inserts, Mil-Spec Fasteners, Socket Head Cap Screw, Socket Products | Tags: Case Study, Certificate of conformance, COC, DFARS Compliant, Domestic Fasteners, manufacturing, Mil-spec, Mil-spec fasteners, Mil-Spec Fasteners Cross-Reference, Mil-Spec Fasteners Distributor, Mil-Spec Fasteners Supplier, Mil-Spec Socket Cap Screws, MTRs, Precision Engineering, Precision Manufacturers, Socket Head Cap Screw Leave a comment
A Buyer’s Case Study on Compliance + Speed
If you sell into the defense or aerospace industry, “finding a screw” is never just finding a screw. The part has to be dimensionally and chemically correct and compliant, with the documentation to prove it.
This is where many procurement teams get stuck: the hardware exists, but the paper trail doesn’t… or the lead time blows up the schedule.
The MF Supply Value Proposition
If you have a commercial part on a BOM that now needs DFARS / Buy American + documentation, MF Supply helps you do one of two things:
- Convert the requirement into the correct Mil-Spec / spec-controlled equivalent (form/fit/function + compliance + paperwork).
- Source or produce a DFARS-compliant version of a commercial catalog part with shorter lead times and with the right cert package.
You get the part you need, on time, with the compliance paperwork you need without playing supplier roulette.
What DFARS/Buy American Actually Means for Fasteners
For fasteners made from specialty metals (including many stainless and high-alloy steels), DFARS requires qualifying melt/manufacture origin. But the “gotcha” is simple: If you can’t document it, it doesn’t count.
Typical documentation packages include:
- Manufacturer Certificate of Conformance (COC)
- Country-of-origin / DFARs specialty metal compliance statements
- Material Test Reports (MTRs)
Visit the DPC website, section 252.225, to keep up to date with DFARs requirements, which were updated January 2023. Click here and scroll to 7009 for more information: 252.225-7000 Buy American Act – Balance of Payments Program Certificate.
The Challenge: Compliant Part, Short Lead Time, Complete Documentation
Many “available” fasteners on the market are:
- Not DFARS compliant
- Not available with COC/MTR
- Not stocked (or stocked without the right chain-of-custody), leading to long lead times
The Situation: “We Need It Now… and It Needs To Pass Audit.”
A manufacturer supporting a defense aerospace assembly needed a 10-32 x 3/4 socket head cap screw in 300-series stainless. The Bill of Materials (BOM) required:
- DFARS-compliant specialty metal
- Manufacturer COC
- MTRs / test reports
- Documented material origin
Their incumbent supplier quoted 26–30 weeks. That was a hard no.
The Solution: Cross-Reference to an In-Stock Mil-Spec Option (With Paperwork)
The buyer searched for DFARS-compliant 10-32 x 3/4 socket head cap screws in stainless steel and landed on MF Supply’s product page for: NAS1351C3-12 (10-32 x 3/4) Mil-Spec socket head cap screw, stainless, DFARS
MF Supply worked with the buyer to:
- Confirm the correct spec-controlled requirement
- Pull active inventory from a qualified supply chain
- Provide COC + MTR documentation
- Confirm DFARS specialty metal origin with documentation
The result
- 26+ week production delay avoided
- Compliance risk eliminated
- Audit-ready paperwork shipped with the order
When Cross-Referencing Helps (And When It Doesn’t)
Cross-referencing can reduce lead times and risk when it’s validated upfront:
- Form/fit/function confirmed
- Spec requirements verified (AN/MS/NAS/NASM, etc.)
- Documentation requirements confirmed (COC, MTR, COO/DFARS statements)
Substitution only works when the part and the paperwork both match the requirement.
Buyer Takeaway: In-Stock + Paperwork=Shorter Lead Times, No Surprises
If your customer needs DFARS / Buy American compliance, always ask:
- Can you provide a COC?
- Can you provide DFARS specialty metal documentation?
- Is material origin documented?
- Is it in stock, or are you quoting a 20–30 week lead time?
At MF Supply, inventory is backed by documentation, so you don’t have to choose between speed and compliance.
Need DFARS-compliant screws fast and with paperwork?
Send your part number, drawing, or BOM requirements. We’ll confirm the right spec, validate compliance, and quote the fastest safe path.
And yes, “finding the right screw for you” isn’t just our tagline. It’s our favorite sport.
Related:
- MF Supply Cross-reference playbook
- Buyer’s Guide to Mil-Spec Fasteners
- Mil-Spec DFARS!? What the heck is that?
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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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].
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.
How to Use MF Supply’s Cross-Reference Tables to Find Equivalent Fasteners Faster
Posted: November 18, 2025 Filed under: Branded Fasteners, Commercial Fasteners, Cross Reference Charts, dowel pin, E-Z LOK, Functional Equivalents, helical wire inserts, keensert, key-locking inserts, Metric Fasteners, Mil-Spec, Mil-Spec Electronic Hardware, Mil-Spec Fasteners, Precision Shoulder Screws, Threaded Inserts | Tags: Hardware, Helical Inserts Cross Reference, Keenserts, Keenserts Cross Reference, manufacturing, Metric Fasteners Cross-Reference, Mil-Spec Fasteners Cross-Reference, MS51830, ms51831, MS51832, Precision Engineering, Precision Manufacturers, Precision Shoulder Screws Cross Reference, threaded inserts Leave a comment
Many popular fastener brands, from Keensert® key-locking inserts to precision shoulder screws, have alternative form-fit-function equivalents available in Mil-Spec, commercial or generic versions. The fastest way to identify the right alternative without guessing is by using cross-reference tables.
At MF Supply, we’ve built and curated multiple product-specific cross-reference tables so buyers can confidently match OEM brands, Mil-Spec part numbers, and generic equivalents, saving time, money, and lead time risk, while maintaining quality and compliance.
Below is your quick-start playbook.
What Product Categories Have Cross-Reference Tables?
We currently publish, maintain, or reference cross-reference data for high-demand categories. On our website, the Inch, Mil-Spec & Metric Fasteners Cross-Reference Charts category serves as your central hub. Once there, you can drill down into specific product families:
- Helical Inserts
- Hex Head Cap Screws
- Keensert® style threaded inserts
- Knurled Thumb Screws
- Precision Dowel Pins
- Precision Shoulder Screws
- Retaining Rings
- Self-Clinching Fasteners (nuts, studs & standoffs)
- Spacers (round & hex)
- Standoffs (round & hex)
- Threaded Inserts for Metal (E-Z LOK equivalents)
Each product family/category links to cross-reference charts that map:
- OEM brand part numbers/products
- Mil-Spec (MS, NAS, MA, NA) series (if applicable)
- Generic functional equivalents
- Sizes, materials and other specifications
Popular product categories include adhesives and sealants, anchors, bits and nutsetters, cage nuts, flex type lock nuts, handles, Keenserts®, knurled thumb screws, nylon insert stop nuts, precision shoulder screws, retaining rings, rivets & blind threaded inserts, self-clinching, fasteners, spacers and standoffs, speed clips, spring nuts, weld nuts, weld studs, and woodworking screws.
Brands Commonly Included in Cross-Reference Comparisons
3 STAR RIVETS USA, ABBATRON®, ALCOA, AMATOM®, APEX®, ARCONIC®, ATLAS®, AVDEL®, AVK®, B. F. GOODRICH, BOLLHOFF, BUCKEYE, CAPTIVE, CELUS®, CHERRY®, CONCORD, EZ-Lok, FASTENAL, GESIPA®, GRIPCO®, GLOBE ELECTRONICS, GRAINGER, H. H. SMITH, HOWMET, HUCK, INDUX, INTERFAST, KEENSERT®, KEYSTONE, LOCTITE®, LYN-TRON, MACLEANESNA®, MARSON®, MCMASTER-CARR, MISUMI, MSC INDUSTRIAL, PEM®, PIC DESIGN®, POP®, POWERS®, QUICKSCREWS, RAF, RED HEAD®, ROTOR CLIP®, SHEREX, SIMPSON, SOUTHCO®, SPS TECHNOLOGIES, TINNERMAN®, UNICORP, U. S. ANCHOR. VIP, W. M. BERG, W. W. GRAINGER, WALDES TRUARC® and many more.
How to Use Our Cross-Reference Tables (5-Step Method)
When you’re chasing cost savings, cutting lead time, or finding a compliant alternative, our cross-reference charts make it fast and fail-proof. Here’s the playbook:
- Visit our Cross-Reference Hub
Head to the Inch, Mil-Spec & Metric Fastener Cross-Reference Charts on mfsupply.com. - Select Your Product Category
Pick the family you’re working with (Keenserts®, shoulder screws, dowel pins, etc.). - Locate Your Identifier
Find the OEM brand part number or Mil-Spec/NAS/MA/NA code inside the chart. - Match the Technical Requirements
Click through to the referenced item and verify the functional equivalency: material, plating/finish, thread/diameter, length, fit/series, and any spec callouts. - Order or Request a Quote With Requirements
Purchase online or submit an RFQ — and let us know if you need COC, MTR, DFARS, REACH/RoHS, Country of Origin, or other compliance docs.
When to Cross vs. When to Stay On Brand
Fastener buyers often ask: How can I determine if I must use the brand name or if I can cross to a generic part?
Use this handy 4 point checklist as your guide:
- Does your bill of materials specifically call for the OEM brand-name fastener or component?
- Can you live with the lead time or will having parts sooner improve delivery of the final product?
- Will your supplier provide a certificate of conformance?
- Will saving money help you be more competitive?
Do not cross when:
- The BOM mandates the OEM brand, and the end customer may not be flexible
- Traceability or contract terms prohibit substitution
Case Studies Proving It Works
| Product Type | Result | Savings | Lead-Time Impact |
| Precision Shoulder Screw | Crossed to 8 valid equivalents | Major cost reduction | Immediate availability |
| Keensert® Key-Locking Insert | Crossed to Mil-Spec equivalent | 59% saving | 28 weeks → 5 weeks |
Need Help? We’ll Build the Cross For You
If you’re unsure, send us the part number, drawing, photo, or BOM section. We’ll match it, validate compliance, and offer your best-value, best-availability option.
Email RFQs to: sales@mfsupply.com
“Finding the right screw for you” is our tagline 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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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].
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.
Mastering Mil-Spec Dowel Pins: Fit, Material, and Series Made Simple
Posted: October 28, 2025 Filed under: dowel pin, M21143, Mil-Spec, Mil-Spec Fasteners, Mil-Spec Precision Dowel Pins, MS16555, MS16555, MS16556 and Mil-P-21143., MS16556, PRECISION DOWEL PIN | Tags: Fasteners, Guide, M21143, Mil-Spec Dowel Pins, Mil-spec fasteners, Mil-Spec Fasteners Distributor, Mil-Spec Fasteners Supplier, Mil-Spec Precision Dowel Pins, Military Dowel Pins, Military Fasteners, Military Fasteners Supplier, MS Dowel Pins, MS16555, MS16556 Leave a comment
What Makes Mil-Spec Dowel Pins Different?
Mil-Spec (Military Standard) dowel pins are precision-ground, solid headless fasteners engineered for exact alignment, location, and secure assembly of components in aerospace, defense, and precision manufacturing.
They are produced under strict Mil-Spec specifications to ensure dimensional accuracy, repeatability, and conformance. Unlike commercial pins, Mil-Spec versions must be tested and certified for mechanical properties, hardness, and finish supported by documentation packages that may include Material Test Reports (MTRs), Certificates of Conformance (COCs), Heat Treat Certifications and DFARs compliance statements.
Dowel pins are commonly used as hinges, shafts, pivots, or locating devices to align or secure parts within precision assemblies or fixtures.
Four Common Mil-Spec Dowel Pin Series
Not all dowel pins are created equal. Each Mil-Spec series follows strict guidelines for fit, tolerance, material and other attributes to ensure accuracy and repeatability in demanding applications. Whether double-chamfered or featuring a radius and chamfer combination, these pins play a vital role in precision alignment. Below we deconstruct the taxonomy and attributes of the four series most frequently used in military and aerospace manufacturing.
1 – MS16555 — Standard Headless Dowel Pin (Press Fit)
Equivalent: Similar to ASME B18.8.2 standard series
- Design: Straight, solid headless dowel pin normally made with a chamfered crown on one end and a chamfer on the other
- Fit Type: Provides a standard interference/press fit
- Tolerance: -0 / +0.0002 over nominal size
- Material Options:
- MS16555-1 to -145: Steel (Carbon or Alloy), hardened
- MS16555-301 to -444: Phosphate-coated Steel, hardened
- MS16555-601 to -744: CRES 410/416 Stainless Steel, hardened and passivated
- Diameter Range: 1/16″ (.0626–.0628) to 1″ (1.0001–1.0003)
- Length Range: 3/16″ to 6″ (lengths over 3″ may be limited)
- Applications: Ideal for vibration-resistant, high-strength alignment in aircraft and defense assemblies
➡️ Available for purchase online or RFQ
2 – MS16556 — Oversize Headless Dowel Pin (Extended Length / Oversize Fit)
Equivalent: Similar to ASME B18.8.2 oversize standard series
- Design: Straight, solid headless dowel pin normally made with a chamfered crown on one end and a chamfer on the other (Similar to MS16555 with oversize tolerance)
- Fit: Oversize interference fit
- Tolerance: -0 / +0.001 over nominal diameter
- Material Options:
- MS16556-1 to -144: Steel (Carbon or Alloy), hardened
- MS16556-301 to -444: Phosphate-coated Steel, hardened
- MS16556-601 to -744: Stainless Steel, hardened and passivated
- MS16556-801 to -944: Cadmium-plated Steel, hardened
- Diameter Range: 1/16″ to 1″
- Length Range: 3/16″ to 6″ (extended per spec; over 3″ limited)
- Applications: Ideal for worn holes and to replace pins that no longer fit securely.
➡️ Now available for RFQ at mfsupply.com
MIL-P-21143 Series
3 – M21143/1 — CRES 303 Stainless Steel Dowel Pin (Press Fit)
Specification: MIL-P-21143
- Design: Straight, headless pin with .015/.010 x 45° chamfer on both ends
- Fit: Press fit — standard interference fit (referred to as “Oversize” in spec)
- Tolerance: -0 / +0.0002 over nominal
- Material: CRES 303 Stainless Steel
- Diameter Range: 1/16″ to 1″
- Applications: Used to join moving components or in high-precision assemblies requiring corrosion resistance and tight alignment
➡️ Available for RFQ at mfsupply.com
4 – M21143/2 — CRES 303 Stainless Steel Dowel Pin (Slip Fit / Undersize)
- Design: Produced similar to M21143/1, straight, headless dowel pin with precision-ground surfaces, generally produces with a .015/.010 x 45° chamfer both ends
- Fit: Slip fit — slightly undersized for easy removal or adjustment
- Tolerance: +0 / -0.0002 under nominal diameter
- Material: CRES 303 Stainless Steel.
- Applications: Used in assemblies requiring frequent disassembly or maintenance; ideal for prototypes or variable-fit applications
➡️ Available for RFQ at mfsupply.com
Choosing the Right Material
| Material | Key Traits | Common Uses |
| Alloy/Carbon Steel (Plain, Cadmium, Phosphate) | High strength, durable | Heavy-load or high-temp applications |
| CRES 410/416 Stainless Steel | Hardened, corrosion-resistant | Aerospace and defense |
| CRES 303 Stainless Steel | Corrosion-resistant, easy to machine | Slip-fit and/or precision alignment |
All Mil-Spec dowel pins from MF Supply include Manufacturer’s Certificates of Conformance. Full certification packages — MTRs, Dimensional Reports, Heat-Treat, Passivation, and DFARS statements — are available upon request and may incur a fee.
👉 Checkout our Mil-Spec Precision Dowel Pins Cross-Reference Charts
Checklist: Sourcing the Correct Mil-Spec Dowel Pin
Before placing your RFQ or order, confirm:
- Specification / Part Number – e.g., MS16555, MS16556, M21143/1, M21143/2. Check the diameter, length, tolerance, material and all specs to the Mil-Spec print.
- Material & Finish – Match environment and strength needs.
- Fit / Tolerance – Choose standard press fit, oversize, or slip fit as required.
- Documentation – Determine your paperwork requirements at every stage of the process from initial RFQ to receiving inspection to insure audit readiness.
Mil-Spec Dowel Pins from MF Supply
MF Supply is your WBE/WOSB-certified U.S. distributor for certified, commercial, and custom dowel pins, including:
- MS16555, MS16556, M21143/1, and M21143/2 series
- Alloy and CRES Stainless Steel options
- Certification packages (MTRs, COCs, Passivation, DFARS, Heat-Treat)
- Fast RFQ turnaround and domestic stock for quick delivery
- Made to order option for parts that are not COTs or for special sizes, materials and tolerances
We’re proud to announce that MS16556 dowel pins are now available for RFQ — joining our comprehensive Mil-Spec, metric, and precision dowel pin lineup.
👉 Visit MF Supply to request a quote or browse our catalog.
We are your Purchasing Department’s Secret Weapon for Mil-Spec hardware!
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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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].
Mil-Spec Socket Cap Screws: A Complete Buyer’s Guide
Posted: September 22, 2025 Filed under: Mil-Spec, Mil-Spec Fasteners, MS16995, MS16996, MS16997, MS16998, MS24671, NAS1351, NAS1352, Socket Head Cap Screw | Tags: Fasteners, Guide, Mil-spec fasteners, Mil-Spec Fasteners Distributor, Mil-Spec Fasteners Supplier, Mil-Spec Socket Head Cap Screws, Military Fasteners, Military Fasteners Supplier, MS16995, MS16996, MS16997, MS16998, MS24671, NAS1351, NAS1352, Socket Cap Screws Leave a comment
When it comes to aerospace, defense, and mission-critical industrial applications, not all socket cap screws are created equal. While commercial socket cap screws can be sufficient for general manufacturing, Mil-Spec socket cap screws are engineered, tested, and certified to meet the stringent requirements of the U.S. military and defense supply chain.
In this guide, we’ll cover:
- The variations of Mil-Spec socket cap screws
- Materials, platings, and optional features
- The part number taxonomy (MS, NAS, NASM, AN designations)
- How Mil-Spec differs from commercial socket caps
- Typical applications and industries
- MF Supply’s Mil-Spec socket cap screw catalog offerings
Variations of Mil-Spec Socket Cap Screws
Mil-Spec socket cap screws (sometimes called MS or NAS socket head cap screws) come in multiple variations to meet specific performance requirements: The 2 main Mil-Spec standards are:
- Standard socket head cap screws – Cylindrical head, hexagonal drive. Designed for high-strength fastening where space is limited.
- Flat socket cap screws – Used in clearance-sensitive applications where flush mounting is critical.
Note: Low Head and Button Head socket cap screws do not have a Mil-Spec equivalent.
Mil-Spec socket head cap screws come in several varieties, including:
- Drilled heads (safety wire holes) – Feature cross-drilled holes in the head to allow safety wiring, preventing loosening in high-vibration environments like aircraft engines.
- Thread-locking (pre-applied patch) – Includes a nylon or chemical locking element on the threads, providing resistance to vibration loosening.
- Vent/drilled-through screws – Designed to eliminate trapped gas or contamination in vacuum or cleanroom environments.
Note: Varieties including threadlocking, drilled heads and vented options are less common and may only be available per special order with minimums and lead times.
Materials & Platings
Mil-Spec socket cap screws are offered in specific materials and platings with mechanical properties that meet or exceed ASTM/SAE standards. Common options include:
- Alloy Steel – High tensile strength, black oxide or cadmium plated for corrosion resistance
- CRES Stainless Steel (18-8/300 series stainless steel) – Corrosion resistance, often used in aerospace and marine environments
- CRES A286 Stainless Steel superalloy – Extreme temperature resistance, high strength and with excellent corrosion & oxidation resistance
Note: SS316 stainless steel is less common and may only be available by special order with minimums and lead times.
Platings and Coatings:
- Black Oxide (MIL-C-13924, Class 1) – Standard corrosion resistance
- Cadmium Plating (QQ-P-416) – Excellent corrosion resistance and lubricity. Widely specified in legacy Mil-Spec standards.
- Passivation (for stainless steels, QQ-P-35) – Removes surface contaminants and improves corrosion resistance.
Part Number Taxonomy
Military grade fasteners or “Mil-Spec” fasteners are usually designated by an AN, MS, NAS or NASM prefix followed by a part number. Each of these prefixes is an abbreviation: NAS stands for National Aerospace Standard and MS stands for Military Standard.
The Defense Supply Center Philadelphia (DSCP), part of the DLA (Defense Logistics Agency), has a Qualified Suppliers List for Manufacturers (QSLM) identifying pre-qualified sources for certain products purchased by DSCP. Referred to also as the QPL (Qualified Products List), manufacturers on this list are recognized by DSCP as meeting all necessary criteria, particularly regarding quality control and paperwork.
Each part number defines key parameters: head style, material, finish, thread class, and whether features like drilled heads or locking elements are included.
The main core part numbers identifying standard Mil-Spec socket head cap screws are MS16995, MS16996, MS16997, MS16998, NAS1351, and NAS1352. Flat head socket head cap screws fall under parts MS24671 and MS24672.
- MS (Military Standard) – Legacy part numbers (e.g., MS16995), still widely used in aerospace and defense
- NAS (National Aerospace Standards) – High-performance standards developed for aerospace (e.g., NAS1351, NAS1352)
- NASM – Updated versions of NAS standards under SAE governance
- AN (Army-Navy) – Older standards, often superseded by MS or NAS numbers
The base part is followed by a Material Code:
- “-” = Alloy Steel
- “C” = Corrosion Resistance Steel (18-8 stainless steel)
- “N” = Heat-Resistant Steel (A286)
- Let’s further break down a common Mil-Spec socket cap:
- For example: NAS1352N028, sometimes written as NAS1352N02-8
- 2-56 X 1/2 Mil-Spec Socket Head Cap Screw A286 Stainless Steel DFAR
- NAS1352 = Coarse thread Socket Head cap screw
- N = Heat-Resistant Steel (A286)
- 02 = 2-56 Diameter
- 8 = .500 or 1/2 screw length
Note: The Aerospace Industries Association maintains an updated list of NAS parts available to members and/or for purchase.
Why Mil-Spec Socket Caps Are Different from Commercial
Commercial socket caps may look identical to Mil-Spec socket caps. However, commercial fasteners may lack the controlled processes, documentation, and certifications required for military or aerospace projects.
Differences between Mil-Spec and commercial socket head cap screws may include:
1. Certification & Paperwork
Available Paperwork may include:
- Manufacturer’s Certificate of Conformance (C of C)
- Lot and heat traceability
- Dimensional testing
- Material Test Reports (MTRs)
- DFARS compliance certification for defense projects
2. Testing
Mil-Spec socket caps undergo rigorous mechanical, dimensional, and sometimes nondestructive testing to verify hardness, tensile strength, shear strength, plating thickness, and more.
3. Authorized Manufacturers
Manufacturers listed on the QPL (Qualified Products List), the Qualified Suppliers List for Manufacturers (QSLM), or those approved under aerospace quality systems (AS9100, NADCAP for plating, etc.) are authorized to produce Mil-Spec socket caps. This ensures supply chain integrity and reliability in defense applications.
Applications
Mil-Spec socket head cap screws are commonly used in:
- Aerospace & Defense – Aircraft structures, engines, avionics, and ground support equipment
- Military Vehicles & Marine – Tanks, ships, submarines, and defense electronics
Other industries use Mil-Spec fasteners because of their quality and traceability. Two examples include Precision Manufacturing where vibration, temperature extremes, or strict compliance require certified fasteners, and Medical & High-Tech Industries where cleanrooms, vacuums, or corrosive environments require traceability is essential.
MF Supply’s Mil-Spec Socket Cap Offerings
At MF Supply, we stock and source a broad catalog of Mil-Spec socket head cap screws including:
- NAS1351 & NAS1352
- MS16995, MS16996, MS16997, MS16998
- MS24671 & MS24672
- Variants with drilled heads, vent holes, and locking elements
- Multiple materials, platings, and DFARS-compliant options
We partner with only qualified U.S. and global manufacturers and provide full certification packages upon request.
Beyond strength and performance, the real differentiators are the certifications, testing, and compliance requirements that ensure supply chain integrity.
MF Supply has over 50 years of experience supplying Mil-Spec, DFARS-compliant, and certified hardware. Whether you need a handful of parts or long-term stocking solutions, we’re Your Purchasing Department’s Secret Weapon.
👉 Explore Our Catalog of Mil-Spec Socket Cap Screws or Request a Quote today.
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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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].
A286 Stainless Steel Keenserts®: Stronger Threads for High-Temperature & Corrosive Applications
Posted: August 19, 2025 Filed under: A286 Keenserts, Fasteners, keensert, key-locking inserts, Threaded Bushing, Threaded Fasteners, Threaded Inserts | Tags: A286, A286 Keenserts, A286 Keylocking Inserts, A286 Stainless Steel, A286 Stainless Steel Keenserts, Inserts, inserts for manufacturers, Keenserts, Key Locking Inserts, manufacturing, Metric A286 Keenserts, Mil-Spec A286 Keenserts, threaded bushing, threaded fastener Leave a comment
If your next thread reinforcement or repair project involves corrosive, high-load, or high-temperature conditions, A286 stainless steel Keenserts® (key-locking inserts) may be your best choice.
In this guide, you’ll learn:
- What A286 Superalloy is
- Key benefits of using A286 Keenserts®
- How to identify A286 in part numbers
- Available series and styles
- Industries and applications that rely on A286 Keenserts®
What Is A286?
A286 is an iron–nickel–chromium stainless steel superalloy known for:
- High strength (maintains properties at up to 1300°F / 700°C)
- Excellent corrosion & oxidation resistance
- Performance in both extreme heat and low-temperature environments
It is widely used in gas turbines, aerospace components, and assemblies that face frequent exposure to extreme conditions. This alloy can also be age-hardened to improve ductility in notched sections.
Why Choose A286 Keenserts®?
Keenserts® are solid, one-piece threaded inserts designed for permanent, high-strength threads—especially in softer materials or under intense heat and torque.
Here’s why A286 stainless steel Keenserts® stand out:
1 – High-Temperature Strength
A286 retains its strength where others fail—ideal for exhaust zones, turbines, and engine bays. Its oxidation resistance and heat-treat response ensure long-lasting performance.
2 – Mechanical Locking Keys
Drive keys lock the insert into the parent material, resisting torque-out and rotation even in vibration-heavy assemblies. This ensures reusable, secure threads during multiple maintenance cycles.
3 – Aerospace-Grade Quality
With minimum tensile strength of 140 ksi, finishes meeting AMS 2700 / ASTM B700, and 302 CRES keys, these inserts meet stringent military and aerospace specs.
4 – Simple Installation
Uses standard drills and taps—no STI tap required. Just tap the hole, insert, and drive in the keys. For parent materials harder than RC30, a broaching tool is recommended to cut key slots.
Note: A286 can be costlier and harder to machine, with potential long lead times.
How to Identify A286 in Part Numbers
Look for these designators:
- Mil-Spec: CA (e.g., MS51831CA204, NAS1395CA6)
- Commercial: JT (e.g., KNH624JT)
- Metric Commercial: T (e.g. KNCM4x0.7T)
- Metric Mil-Spec: NA Series NA0147, NA0149, & NA0151
Example:
- MS51831CA204, NAS1395CA6, and KNH624JT all describe the same insert:
3/8-24 ID x 9/16-12 OD Heavy-Duty A286 CRES Key-Locking Insert.
A286 Keenserts® Series & Styles
Beyond their core benefits, A286 Keenserts® key-locking inserts come in a range of specialized series designed for specific applications:
- Miniature (KNC) & (NA0147): Ultra-lightweight for electronics & avionics. Inch/Mil-Spec (2-56 to 1/4-20), Metric (M2–M4).
- Thin Wall (KN/KNM) & (NA0149): For tight spaces; precision engineering. Inch/Mil-Spec (10-24 to 1/2-13), Metric (M5–M12).
- Heavy-Duty (KNH/KNHM) & (NA0151): For high-stress uses—automotive, heavy machinery. Inch/Mil-Spec (1/4-20 to 7/8-14), Metric (M4–M24).
- Extra Heavy-Duty (KNHXH): For extreme load and torque; industrial & military. Inch/Mil-Spec (1/4-20 to 7/8-14). No Metric Option.
Other Series and styles, including Floating (KNK) Key-locking inserts may be available for special order.
In general, A286 Keenserts® will be manufactured to meet aerospace and military standards: MS51830CA, MS51831CA, MS51832CA, NAS1394CA, NAS1395CA, NA0147, NA0149, NA0151.
Industries That Rely on A286 Keenserts®
- Aerospace: Structural components exposed to heat, load, and vibration.
- Oil & Gas: Equipment facing high heat and corrosion.
- Automotive & Defense: Frequent assembly/disassembly in performance and military systems.
- Power Generation: Turbines and engine components under oxidative stress.
MF Supply, Your Trusted Source for A286 Keensert® Style Key-Locking Inserts
MF Supply is a WBE/WOSB-certified supplier of A286 Keensert® style key-locking inserts, serving manufacturers, engineers, government, and industry.
We balance cost, quality, availability, and certification needs (DFARS, COC, etc.), and most popular sizes ship within 24 hours.
Browse Our Selection & Shop A286 Keenserts® Now!
Please plan ahead as less popular sizes may involve minimum order and long lead times.
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.
Why Use Nitronic Keenserts vs. Nitronic Helicoils?
Posted: July 29, 2025 Filed under: Brand equivalents, Fasteners, keensert, key-locking inserts, Nitronic 60 Keenserts, Threaded Bushing, Threaded Fasteners, Threaded Inserts | Tags: Inserts, inserts for manufacturers, Keenserts, Key-Locking Inserts, manufacturing, Mil-Spec Nitronic Keenserts, Nitroinc, Nitronic 60, Nitronic 60 Keenserts, Nitronic Keenserts, Nitronic Keylocking Inserts, threaded bushing, threaded fastener Leave a comment
If you need Nitronic material for your thread repair or thread reinforcement project, you might be deciding between helical and/or key-locking inserts. Here are some considerations to help you evaluate which product will best solve for your needs.
But first, let’s take a closer look at Nitronic 60…
What Makes Nitronic Special?
Nitronic 60, the most commonly used Nitronic material used to manufacture inserts, is a high-performance stainless steel alloy enriched with nitrogen, renowned for its exceptional wear, galling, and corrosion resistance. It provides exceptional resistance to crevice corrosion, general corrosion and high temperature oxidation, This makes it ideal for applications that require durable and reliable thread repair or reinforcement in marine environments, chemical processing equipment, and assemblies that require frequent disassembly.
Nitronic Keenserts® vs. Helicoils
Helicoils (helical inserts) are used for thread repair and reinforcement. They are considered the simplest way to repair stripped or damaged threads. 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.
So what’s the the catch?
Helicals have certain limitations that Keenserts® (key-locking inserts) overcome. 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.
If your project calls for Nitronic inserts, below are four reasons why you should consider choosing Keensert® style key-locking inserts vs. Nitronic helical inserts:
- Superior Strength and Stability: Nitronic key-locking inserts have locking keys that mechanically lock the insert into place, offering superior resistance to vibration and torque-out compared to helical inserts, which rely solely on friction.
- Enhanced Durability: The durable design of key-locking inserts provides greater resistance against thread stripping and wear, making them suitable for repeated assembly and disassembly without compromising the integrity of the threads.
- Corrosion and Galling Resistance: Both helical inserts and key-locking inserts made from Nitronic 60 offer excellent corrosion resistance. However, key-locking inserts provide additional structural integrity, especially crucial in harsh environments where component failure is not an option.
- Easier Installation and Maintenance: Nitronic key-locking inserts require no special taps or tools for installation beyond standard equipment—a pneumatic power tool is recommended if installing key-locking inserts in the thousands—reducing downtime during maintenance or initial assembly. Their solid, one-piece design simplifies handling and reduces the likelihood of installation errors.
Unsure which Nitronic 60 insert is ideal for your next thread-repair or reinforcement project? Send us your questions, we’re here to help!
Shop Nitronic Keensert® Style Key-Locking Inserts at MF Supply!
Nitronic Keenserts® Series and Standards Available
In addition to the previous reasons, Nitronic Keenserts® style key-locking inserts are also available in a variety of specialized styles/series and standards that are tailored for specific applications:
- Miniature (KNC): Ideal for lightweight applications where space and weight constraints are critical, such as electronics or avionics. Available inch/imperial and Mil-Spec sizes run from 2-52 through 1/4-20 inches.
- Thin Wall (KN & KNM): Excellent for limited-space installations, providing strength without adding significant bulk, commonly used in precision engineering. Available inch/imperial and Mil-Spec sizes run from 10-24 through 1/2-20 inches, and metric sizes run from M5 through M12.
- Heavy-Duty (KNH & KNHM): Designed for high-stress applications where structural integrity and robust fastening capabilities are essential, such as automotive and heavy machinery. Available inch/imperial and Mil-Spec sizes run from 1-8 through 7/8-14 inches, and metric sizes run from M4 through M24.
- Extra Heavy-Duty (KNHXH): Engineered for extreme load-bearing and high-torque scenarios, perfect for heavy industrial and military applications demanding maximum strength and durability. Available inch/imperial and Mil-Spec sizes run from 1-8 through 7/8-14 inches.
Nitronic Keenserts® style key-locking inserts can also follow/meet stringent aerospace and military standards, including:
These styles/series and standards provide adequate solutions ranging from lightweight applications in aerospace to heavy-duty industrial settings.
Industries That Benefit From Nitronic Keenserts®
Nitronic Keensert® style key-locking inserts are ideal for industries that demand trusted and dependable reliability, such as:
- Aerospace: Nitronic key-locking inserts are essential for structural components requiring exceptional strength and resistance to vibration.
- Marine: Nitronic key-locking inserts are able to withstand harsh saltwater environments without corrosion.
- Automotive and Defense: Nitronic key-locking inserts are ideal for parts undergoing frequent assembly and disassembly.
- Chemical Processing: Nitronic key-locking inserts are extremely resilient under highly corrosive conditions.
MF Supply, Your Trusted Source for Nitronic Keensert® Style Key-Locking Inserts
MF Supply is a WBE/WOSB certified business, and a leading supplier of Nitronic Keensert® style key-locking inserts for manufacturers, engineers, government and industry. At MF Supply, we understand the industry’s need to balance cost, quality, availability, and paperwork/certification requirements—DFARS, COC, and more. Most of our popular Nitronic key-locking inserts sizes are in stock and ready to ship within 24 hours.
Buy Nitronic Keensert® Style Key-Locking Inserts From MF Supply!
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.
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 comment
MF 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.
Top 17 Keensert® Questions: Expert Answers to Common Questions (Part 3)
Posted: May 22, 2025 Filed under: Inch and Mil-Spec Keensert, keensert, Keenserts Frequently Asked Questions | Tags: Expert Answers to Keenserts Frequently Asked Questions, Keensert FAQs Part 3, Keensert Guide, Keensert Inserts, Keensert Materials Available, Keensert Supplier, Key Locking Inserts, Self-Locking Keensert Leave a comment
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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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)
Posted: April 28, 2025 Filed under: Inch and Mil-Spec Keensert, keensert, Keenserts Frequently Asked Questions | Tags: Expert Answers to Keenserts Frequently Asked Questions, Keensert FAQs Part 2, Keensert Guide, Keensert Inserts, Keensert Materials Available, Keensert Supplier, Key Locking Inserts, Self-Locking Keensert Leave a comment
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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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 1)
Posted: March 27, 2025 Filed under: Inch and Mil-Spec Keensert, keensert, Keenserts Frequently Asked Questions, Metric Keensert | Tags: Expert Answers to Keenserts Frequently Asked Questions, Keensert FAQs, Keensert Guide, Keensert Inserts, Keensert Installation Tools, Keensert Supplier, Key-Locking Inserts, supply chain Leave a comment
Navigating the world of key-locking inserts—Keenserts®—doesn’t have to be complicated. Our comprehensive guide with 17 frequently asked questions cuts through the confusion, addressing the top issues related to selecting, shopping for and installing key locking inserts. In this first installment of our 3 part series, we’ll cover the first 7 questions which focus on the fundamentals, including the differences between self-locking and standard inserts, installation essentials, and common questions when drilling and tapping the holes in the parent material.
1 – What is the difference between a key locking and a self-locking Keensert®?
A key locking threaded insert, also known by its trademarked name Keensert®, is a solid bushing style insert with both internal and external threads. It has wedges or “keys” on one end that lock it into place after installation, preventing loosening due to vibration. All Keenserts® are key-locking inserts. Key-locking inserts come in self-locking and non-self-locking styles (sometimes referred to as free-running). Self-locking style key-locking inserts have a distorted internal thread that creates a mechanical lock, making them some of the strongest inserts available. This mechanical self-locking feature is stronger than adhesive-based chemical thread-lockers.
2 – What tools do I need to install a key-locking insert?
To properly install a key-locking insert, AKA Keensert®, you will need the following tools:
- Drill: to make a hole in the parent material.
- Tap: To tap threads that will accept the external thread of the insert.
- Keensert® Installation Tool & Hammer: to drive the keys into the parent material.
Depending upon your application, you may also require a countersink tool and a broaching tool. Note: If you have a few hundred inserts to install, the manual process detailed above works 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.
3 – How do I install key-locking Inserts?
To manually install a key-locking insert it requires a 4-step process:
- Drill a hole and countersink the parent material. Note: The drill size is specific to the Keensert® you are installing.
- Tap threads into the parent material according to the insert’s external thread, pitch and tolerance.
- Manually screw the key-locking insert into the tapped hole.
- Place the installation tool on top of the insert. Strike with a hammer to drive down the locking keys creating a mechanical lock.
4 – What is a broaching tool and when will I need one?
A broaching tool is an extra installation tool that is used in hard material. Parent materials harder than RC30, such as A286, A4140 or anodized aluminum may require the tapped holes be broached prior to installing the key-locking insert. The broaching tool has blades that create slots so the keys can be driven into the parent material.
5 – Where do I find the drill size to install a key-locking insert?
The drill size for a key-locking insert is typically found in the product specifications or installation guide provided by the manufacturer.
Note: The outer diameter of Keenserts® are slightly larger than the standard drill hole to ensure a tight fit and sufficient thread engagement in the base material, compensating for tapped hole variations.
6 – Where do I find the tap size to install a key-locking insert?
The tap size for a key-locking insert is typically found in the product specifications or installation guide provided by the manufacturer. The tap will typically match the size, pitch and tolerance of the insert’s external diameter and thread.
7 – How do I find the correct tool to install my Keensert®?
The correct installation tool is usually specified by the Keensert® manufacturer and can be found in the product’s documentation or on the manufacturer’s website. Installation tools are specific to the external and internal diameter of each unique insert part number. Note: Some tools work for multiple sizes.
Stay tuned for the next installment in this series, where we’ll dive into frequently asked questions about Keensert® measurement differences, material selection options, and more!
In the meantime, 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.
Your Purchasing Department’s Secret Weapon!
Here are 5 reasons to buy from MF Supply
- 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].