Precision Shoulder Screws!? What the heck are those?

What the heck are Precision Shoulder Screws?

Here we go again, with our “what the heck is that” series refreshed for 2023, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. Today, we will re-introduce you to the Shoulder Screw!

What is a Precision Shoulder Screw? 

Shoulder Screws, which are sometimes called Shoulder Bolts or Stripper Bolts, are (generally) hex socket screws with an enlarged, unthreaded cylindrical shoulder under the head.  They are comprised of 3 main parts: the head, the shoulder and the thread.  They come in two basic categories, “Commercial” and “Precision”.

Commercial Shoulder Screws are made to inch standard ANSI ASME B18.8.2.  The size range for the shoulder diameter is from ¼ to 2”.  The thread class is 3A and the tolerance on the shoulder is +.005 /  -.005.

Precision Shoulder screws are sometimes referred to as “tight tolerance” shoulder screws. They are not governed by any official ANSI or ASME standard. The size range for the shoulder diameter is from 3/32 to ½.  The thread class is 2A and the tolerance on the shoulder diameter varies from +.000/-.001 to  -.0005 to -.0015 depending upon the manufacturer. Now that’s precise!

Who uses Shoulder Screws?

Just as Dowel Pins and Retaining Rings are used to locate or hold parts together within a precision assembly or a fixture, so are Precision Shoulder Screws.

Yet shoulder screws are more versatile. When installed, the unthreaded shoulder acts as a shaft for rotating items such as bearings and bushings, precision spacing, machinery support, and motion guiding. Precision Shoulder screws exacting tolerances make them ideal for use with other precision components.

They are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more.

What do I need to consider when selecting Shoulder Screws?

Although Shoulder Screws are offered in a multitude of materials and styles, when it comes to the main commercial and precision offerings, there are a few main issues to consider.

Which Drive and Head Style?

Precision shoulder screws are readily available in hex socket and slotted drives.  Philips drives are available in certain sizes. Torx and Star are available for special order. Typical head styles are a modified fillister with a flat top where the head diameter is about twice the head height. Low head fillisters are available in certain sizes

Which material do I need?

Precision shoulder bolts are readily available in Type 18-8/303 Stainless Steel and 416 Stainless Steel.  316 Stainless Steel, Alloy and other exotic materials are available for special order.

Are there other factors to consider?

When ordering Precision Shoulder screws, specify the Shoulder Diameter, Shoulder length, thread size, material and drive type. For example, an example of a typical Precision Shoulder screw is a ¼ shoulder x ½ long x 10-32 thread in SS18-8 with a hex-socket drive. Non-locking is the most popular style, but locking may also be available.

Precision Shoulder Bolts  often show up under their brand name.  Some of the most popular brands include: BERG, Concord, Globe, PIC, Lyn-tron and RAF. A comprehensive selection of Shoulder Screws is also offered by McMaster-Carr (tight tolerance series), MSC and Grainger.

Finally, Precision Shoulder Screws can also show up under their Mil-spec numbers, which include MS51575 & MS51576 and are DFARS compliant with full paperwork.

Precision Shoulder Screws at MF Supply

We currently offer:

  • The full range of commercial and mil-spec parts, including parts that are DFARS and ROHS compliant.
  • MS51576 Now available for online purchase!
  • Brand names and generic equivalents.
  • Custom made parts per print in non-standard and exotic materials and finishes.
  • Inch, Metric and Mil-Spec sizes.

For more detailed information on Precision Shoulder Screws, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can 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.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 


Mil-Spec DFARS!? What the heck is that?

Welcome to the second edition of our “What the heck is that” series, refreshed for 2023, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. If you sell to the military either directly or indirectly, then you are probably aware of today’s topic:  “DFARS” and “Mil-spec fasteners”.

What does Mil-spec mean anyway?

Before we get into the nitty gritty of DFARS, let’s discuss what makes a “Mil-spec” fastener. Mil-spec is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment. For example, the MS24693C pictured above is a fastener produced according to strict military standards that are maintained by the DLA (Defense Logistics Agency). (https://www.dla.mil/) INSERT THIS LINK I DONT KNOW HOW

Mil-spec fasteners look a lot like their civilian cousins, but, these little guys are made to a specific standard that defines in detail, the screw’s attributes, including: dimensions, tensile strength, hardness, threads, drive type, material qualities and plating, just to name a few.  Mil-spec fasteners are even traceable by lot to designated manufacturers.  The government maintains a list of factories and suppliers who are qualified to manufacture Mil-spec fasteners.  These suppliers have met all the government’s requirements and pass the highest quality control standards. This designation is called Qualified Suppliers List for Manufacturer’s [QSLM].

AKA – Also known as…..

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.  An example of one of the most common and popular Mil-spec machine screws is the MS24693C.  Its commercial equivalent is a Phillips Flat 100 degree Machine Screw in 300 series stainless steel.  Below, we’ll tell you more about this popular fellow.

Who uses Mil-spec Fasteners?

Mil-spec fasteners may be used by anyone manufacturing or servicing military equipment.  Often, the bill of materials calls for specific Mil-spec grade fasteners in accordance with a part number, drawing or procurement requirement.  Some of the most common uses of Mil-spec fasteners include aerospace, naval vessels and weapons systems.

Now, tell me about DFARS…

Almost a decade ago, the term “DFARS Compliant Material” came to the forefront for companies supplying parts and services to the government. The original Federal Acquisition Regulation (FAR) clause 252.225-7014 specified “A Preference for Domestic Specialty Metals.”  What that means in our world is that for fasteners to be DFARS compliant, the metal used to fabricate them must be melted or manufactured in the United States or a qualifying country.

Qualifying countries include: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Egypt, Finland, France, Germany, Greece, Israel, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, United Kingdom of Great Britain and Northern Ireland.

Important Note:  DFARS only pertains to fasteners made from “specialty metals” including: stainless steel, high alloy steel like Grade-BD, or Grade 5 Chromium steel with high chromium content.

Visit the DPC website, section 252.225, to keep up to date with DFARs requirements, which were updated January 2023. Click here: https://www.acq.osd.mil/dpap/dars/dfars/html/current/252225.htm.

An example of a DFARS Mil-Spec Screw please!

As we’ve learned, the MS24693C is actually Phillips Flat 100 degree Machine screws in 300 series stainless steel.   The MS24693-C4 is a 4-40 x 3/8 Phillips Flat 100 Degree Machine Screw in 302 Stainless Steel, and it is one of the most widely used sizes.  Interestingly, the MS24693C superseded the AN662C series, so you might come across the AN662C on an older print of bill of materials.  Keep in mind, with any design or manufacturing decision, the reason for using a specific screw generally rests in the hands of engineering.

Features of the MS24693C

  • Strict military standards ensure performance and reliability
  • Made/melted in the USA or other DFARs-approved country
  • Materials and dimensions meet Federal standard FF-S-92
  • Inspected per Mil-I-45208
  • Full lot traceability, manufacturer’s certification and chemical and physical certification
  • Available in diameters from #0 through 1/4 inch in coarse and fine thread and various lengths

Lessons Learned

Considerations when purchasing MS24693C or other Mil-spec DFARs fasteners.

  1. Always ask for “full certifications”.  This includes part name, part description, date of manufacture, lot number, chemical composition of material, and treatment of material including plating or passivation directly from the manufacturer.
  2. When purchasing Specialty metal screws that qualify for DFARS, at point of purchase, make sure the screws are DFARS.  If you do not specifically ask for DFARS-compliant screws, you might receive screws that don’t meet the DFARS requirements, in which case, they won’t meet military standards.  We’ve learned this the hard way so hopefully you don’t have to!

MS24693C and other Mil-spec DFARS Fasteners in Stock!

Here, at MF Supply, we stock some of the most common Mil-spec Fasteners, including the following: Machine Screws, Socket Screws, Hex Head Cap screws, Nuts, Flat washers and Standoffs and Spacers. Checkout our instock Military Line of fasteners. (LINK HERE https://www.mfsupply.com/mil-spec-fasteners-s/1823.htm) . If you don’t what you need listed, send us an RFQ, as we are sourcing experts!

Visit our website for more detailed information on Mil-spec Fasteners. Also, checkout our military linecard!

And, as always, if you don’t see it listed, ask us.  “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.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 


Buyer’s Guide to Self-Clinching Fasteners 2019

SelfClinchNuts_Multiple

MF Supply continues to expand our offering of products available for purchase online. We are thrilled to offer Self-clinching fasteners available from stock that can be purchased on our website or by email, phone or fax. We are an authorized distributor for Captive Fasteners, a US based manufacturer since 1974, with a factory right here in our NJ backyard!

What are Self-clinching fasteners?

Self-clinching fasteners are generally classified as part of the electronic hardware or precision engineered fastener family and are not governed by IFI, ANSI or ASME standards. A self-clinching fastener, also known as press-fit or clinch style captive fastener, is a part that when pressed into a drilled, punched or machined hole, provides an economical method of joining sheet metal panel applications and is well-suited for use in printed circuit boards.

Self-clinching fasteners are used in many industries; both commercial and aerospace.

Self-clinching Fasteners available at MF Supply

MF Supply offers the full catalog of Captive branded fasteners & PEM® equivalents in inch & metric sizes. We have the following parts available for purchase online, in stock and ready to ship from our national distribution centers:

Additional Series available include, but are not limited to, floating, self-locking, blind-hole, flush, and broaching fasteners.

Steel_Standoff_Prod

How do they work? 

Self-clinching fasteners work by displacing the host material around the mounting hole, causing it to cold flow into a specially designed annular recess. Knurls, serrated rings or ribs on the fastener hold them firmly in place. Self-clinching fasteners become an integral permanent part of the panel or frame and eliminate problems associated with loose hardware. Installation requires access to both sides of the panel and self-clinching fasteners may be installed using any parallel acting squeezing force.

What are the advantages of Self-Clinching fasteners?

Self-clinching fasteners provide strong thread in very thin material & offer high push out and torque out resistance. They take less space and require fewer assembly operations than caged or anchor nuts. They can be installed during fabrication or during final assembly and work well in applications when loose hardware wouldn’t be accessible.

Some of the key advantages include:

  • No special hole preparation, such as chamfering and deburring is required.
  • Low installed costs, fewer parts to handle, fewer assembly steps and less assembly time.
  • No retapping necessary after application.

Reverse side of metal sheet remains flush – no swaged rim protrusion.

What are the differences between branded fasteners like PEM & Captive and generic Self-clinching fasteners?

SelfClinchStudSelf-clinching hardware is frequently referred to by the OEM brand name PEM®. Captive Fastener is a USA based manufacturer and offers functional equivalents to PEM® branded self-clinching fasteners.  In addition to PEM® & Captive, there are a variety of manufacturers of self-clinching fasteners available in the marketplace including the major national catalog brands. Functional alternatives will be equivalent in form fit and function and offer similar performance.

To see if using alternative brands or functional equivalents will work for your business, refer to our handy guide.

We have also included a cross reference lookup table for PEM® product types vs. Captive product series below.

What information for I need for ordering? 

The easiest way to order is by manufacturer part number. If you don’t have one, you’ll need to specify fastener type & style, thread diameter & pitch, fastener length, material and plating. For example: a 10-32 X 3/8 Flush Head Self-Clinching Stud Steel Zinc plated can also be ordered as a PEM® FH-032-6, (or a PEM® FH-032-6-ZI as sometimes PEM® calls out the plating) or a Captive CH1032-6.  This part is also offered by a national catalog brand under part number 93580A166.

Additional Series available include, but are not limited to, floating, self-locking, blind-hole, flush, and broaching fasteners.

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

  1. Full ecommerce enabled website with technical manual available 24/7
  2. Same day drop ship from factory for thousands of items.
  3. Functional Equivalents to expensive brand name fasteners save money and reduce long lead times.
  4. Creatively solve problems including hard to find parts and long lead times
  5. WBE/WOSB Woman Owned Certified Small Business.

What the heck is Mil-spec DFARS? 2019

phillipsflat100degreemachine-new

MS24693C

Welcome to our ongoing “What the heck is that” series, where we discuss some of the unique fasteners and electronic hardware that precision manufacturers use in the design and assembly of their products.  If you sell to the military either directly or indirectly, then you are probably aware of today’s topic: “DFARS” and “Mil-spec fasteners”.

What does Mil-spec mean anyway?

Before we get into the nitty gritty of DFARS, let’s discuss what makes a “Mil-spec” fastener.   Mil-spec is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment. 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. For example, the MS24693C pictured above is a fastener produced according to military standards.

Mil-spec fasteners look a lot like their civilian cousins, but, these little guys are made to a specific standard that defines in detail, the screw’s attributes, including: dimensions, tensile strength, hardness, threads, drive type, material qualities and plating, just to name a few.  Mil-spec fasteners are even traceable by lot to designated manufacturers.  The government maintains a list of factories and suppliers who are qualified to manufacture and distribute Mil-spec fasteners.  These suppliers have met all the government’s requirements and pass the highest quality control standards. This designation is called the Qualified Suppliers List for Manufacturer’s [QSLM].

Who uses Mil-spec Fasteners?

Mil-spec fasteners are used by anyone manufacturing or servicing military equipment.  Often, the bill of materials calls for specific Mil-spec grade fasteners in accordance with a part number, drawing or procurement requirement.  Some of the most common uses of Mil-spec fasteners include aerospace and naval vessels.

Now, tell me about DFARS…

Almost a decade ago, the term “DFARS Compliant Material” came to the forefront for companies supplying parts and services to the government. The original Federal Acquisition Regulation (FAR) clause 252.225-7014 specified “A Preference for Domestic Specialty Metals.”  What that means in our world is that for fasteners to be DFARS compliant, the metal used to fabricate them must be melted or manufactured in the United States or a qualifying country.

The Defense Federal Acquisition Regulation Supplement declares the following:

  • Provides specific acquisition regulations that must be followed in the procurement process for goods and services for the Department of Defense and its contactors.
  • FAR 252.225-7014 specifies “A Preference for Domestic Specialty Metals” in the manufacturing of fasteners.  Berry Act, Buy American.
  • The Specialty metals must be melted and manufactured in the United States or a “Qualifying country.”

What is a Qualifying Country?

Qualifying country” means a country with a reciprocal defense procurement memorandum of understanding or international agreement with the United States in which both countries agree to remove barriers to purchases of supplies produced in the other country or services performed by sources of the other country, and the memorandum or agreement complies, where applicable, with the requirements of section 36 of the Arms Export Control Act (22 U.S.C. 2776) and with 10 U.S.C. 2457.

Qualifying countries include the following 27: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Egypt, Estonia, Finland, France, Germany, Greece, Israel, Italy, Japan, Latvia, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom of Great Britain and Northern Ireland.

To keep up to date with DFARs requirements, visit

www.acq.osd.mil/dpap/dars/dfars/html/current/225_0.htm

What is a Specialty Metal?

Title 48 – Federal Acquisition Regulations System, 252.225-7014 Preference for domestic specialty metals.

SPECIALTY METAL DEFINITION

(1) STEEL

(I) WHERE THE MAXIMUM ALLOY CONTENT EXCEEDS ONE OR MORE OF THE FOLLOWING LIMITS:  MANGANESE, 1.65 PERCENT; SILICON, 0.60 PERCENT; OR COPPER, 0.60 PERCENT; OR

(II) WHICH CONTAINS MORE THAN 0.25 PERCENT OF ANY OF THE FOLLOWING ELEMENTS: ALUMINUM, CHROMIUM, COBALT, COLUMBIUM, MOLYBDENUM, NICKEL, TITANIUM, TUNGSTEN, OR VANADIUM;

(2) METAL ALLOYS CONSISTING OF NICKEL, IRON-NICKEL, AND COBALT BASE ALLOYS CONTAINING A TOTAL OF OTHER ALLOYING METALS (EXCEPT IRON) IN EXCESS OF TEN PERCENT;

(3) TITANIUM AND TITANIUM ALLOYS; OR

(4) ZIRCONIUM AND ZIRCONIUM BASE ALLOYS.

http://www.gpo.gov/fdsys/pkg/CFR-1996-title48-vol3/xml/CFR-1996-title48-vol3-sec252-225-7014.xml

Specialty Metals Include:

  • Stainless steel
  • High alloy steel like Grade-BD
  • Cobalt Chrome Alloys or Grade 5 Chromium steel with high chromium content
  • Nickel Alloys
  • Titanium

Aluminum, Carbon Steel & Copper Alloys are not specialty metals and cannot be DFARS.

What is the difference between Domestic & DFARS?

This is a great question!  There are 3 main factors used to determine the country where a fastener is made and how they are classified.  1) The origin of the metal 2) the country of melt and 3) the country of manufacture.

DFARs only related to specialty metals, and the country of melt & manufacture.  Check with your customer before making any assumptions about what “domestic” means to them.  100% Domestic (metal origin, melt & manufacture) is becoming harder and harder to find. Many products are not available off the shelf and are “made to order” if DFARS or domestic is needed. This will involve a lead time and may have a minimum lot charge.

Lessons Learned: Considerations when purchasing MS24693C or other Mil-spec DFARs fasteners

  • Always ask for “full certifications”.  This includes part name, part description, date of manufacture, lot number, chemical composition of material, and treatment of material including plating or passivation.
  • At point of purchase, make sure the screws are DFARS.  If you do not specifically ask for DFARS-compliant screws, you might receive screws that don’t meet the DFARS requirements, in which case, they won’t meet military standards.  We’ve learned this the hard way so hopefully you don’t have to!

Knurled Thumb Screws Buyer’s Guide

6 Things to Know When Buying Knurled Thumb Screws

 

  1. What is a Knurled Thumb Screw? 

Knurled Thumb Screws are generally classified as part of the electronic hardware or precision fastener family and are not governed by IFI, ANSI or ASME standards. They are solid one piece screws with a cylindrically shaped oversized knurled head, a fully threaded shank construction and a blunt machine screw style end. They are used in applications where periodic manual adjustment is required and finger pressure can supply sufficient tightening torque.

Knurled Thumb Screw

Knurled Thumb Screw with Washer Face

  1. What materials and sizes are available?

Knurled Thumb Screws are readily available off the shelf in type 18-8/303 stainless steel and Aluminum. Some manufacturers stock knurled thumb screws in brass or other materials. Parts are typically supplied without any coating or finish.

Standard stock sizes for the thread diameter are Inch from 4-40 to 1/4-20 with standard lengths up 1” depending upon the manufacturer.

316 stainless steel, alloy and other exotic materials, and special diameters and lengths are available in certain sizes and/or for special order and usually involve a lead time.

  1. What information do I need for ordering?

The easiest way to order is by manufacturer part number. If you don’t have one, you’ll need to specify thread diameter, thread length, head style and material. For example: 6-32 x 3/8″ Knurled Thumb Screws with a Washer Face in Stainless Steel 18-8 is a popular Thumb screw.

Typical head styles are a modified fillister with a flat top where the head diameter is about twice the head height and does not need to be specified. Low head fillisters are available in certain sizes.

  1. What are some of the popular Fastener Brands with Functional Equivalents?

Popular OEM fastener brands include: Amatom, Cambion, Concord, Globe, HH Smith, Keystone, Lyn-tron, Misumi, Pic Design, RAF, and WM Berg. A comprehensive selection of Knurled Thumb Screws is also offered by McMaster-Carr, MSC Industrial and Grainger.

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.

Let’s take the above example of a 6-32 x 3/8″ Knurled Thumb Screws with a Washer Face in Stainless Steel 18-8 is a popular Thumb screw.

This part is offered by the Five brands (yes Five!!) listed below under the following part numbers:

  • Grainger 2KB93
  • Lyn-tron SS7603
  • RAF 7103-SS-0
  • Mcmaster-Carr 99607A116
  • Unicorp THS1004-M07-F16

Each manufacturer has a different price point, but the general physical and chemical dimensions make them functional equivalents or Brand alternatives.

  1. Helpful Hints about Categories of Thumb Screws

There are 2 distinct Thumb Screws categories:

1) Knurled Thumb screws, which are covered here, are part of the precision screw family. They are made 2 ways: Washer face/flared collar or plain/shoulderless. They are typically stocked in aluminum and stainless steel. Other options such as narrow, high profile, slotted may also be available in certain sizes.

2) Type A and Type B Spade style thumb screws are part of the Industrial fastener family per ASME B18.6.8, along with Wing screws. Spade style thumb screws may be available in steel and in diameters up to 1/2”.

  1. What level of certification is required?

Generally, a Certificate of Conformance or a COC is sufficient for your customer. Full certification with material certs and test reports are often available for USA-made and Mil-Spec parts for a fee.

Knurled Thumb Screws at MF Supply

We offer:

  • The full range of commercial and Mil-Spec parts, including parts that are DFARS and RoHS compliant.
  • Brand names and generic equivalents.
  • Custom made parts per print in non-standard and exotic materials and finishes.
  • Inch and metric sizes.

For more detailed information about Knurled Thumb Screws, visit our website. And if you don’t see it 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.


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
robin@mfsupply.com
973-777-5411


Buyer’s Guide to Mil-Spec Fasteners

MS24693C

7 things you need to know

If you sell to the military either directly or indirectly, then you are probably familiar with Mil-spec fasteners. But, what exactly are they and what should you know before buying them? We’d like to help you out with this Seven point buyer’s guide.

  1. What does Mil-spec mean anyway?

Mil-spec or MIL-STD, is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment. Critical fasteners and components used in the production, repair and maintenance of this equipment are classified as “Mil-spec” fasteners. These parts are usually designated by an AN, MS, NAS or NASM prefix followed by a part number (i.e. MS24693C-4). Each of these prefixes is an abbreviation: for example: NAS stands for National Aerospace Standard and MS stands for Military Standard.

  1. What’s the difference between Mil-spec and commercial fasteners?

Mil-spec fasteners look a lot like their civilian cousins, but these little guys are made to a specific standard that defines in detail, the screw’s attributes, including: dimensions, tensile strength, hardness, threads, drive type, material qualities and plating, just to name a few. Mil-spec fasteners are even traceable by lot to designated manufacturers. The government maintains a list of factories that are qualified to manufacture and distribute Mil-spec fasteners. These suppliers have met all the government’s requirements and pass the highest quality control standards. This designation is called Qualified Suppliers List for Manufacturer’s [QSLM]. Commercial fasteners are not held to such specific and exacting standards.

  1. Who uses Mil-Spec Fasteners?

Mil-spec fasteners are used by anyone manufacturing or servicing military equipment. How do you know if your project requires Mil-spec parts? Often, the bill of materials (BOM) calls for specific Mil-spec grade fasteners in accordance with a part number, drawing, NIIN or NSN or procurement requirement. Some of the most common uses of Mil-spec fasteners include aerospace and naval vessels.

  1. Do Mil-Spec fasteners have different features and standards than commercial fasteners?

Mil-spec parts are manufactured and tested to strict military standards ensure performance and reliability. In general, commercial fasteners will not have the same exacting quality standards. Let’s look at a specific example and compare the Mil-Spec MS24693-C4, which is a 4-40 x 3/8 Phillips Flat 100 degree Machine screws in 300 series stainless steel, to its commercial cousin.

Features of the MS24693C-4:

  • ­  Manufactured in an QLSM approved factory
  • ­  Made/melted in the USA or other DFARs* approved country
  • ­  Materials to procurement spec FF-S-92, SAE AIR 4127
  • ­  Cleaned, descaled, passivated to AMS-QQ-P-35; AMS 2700
  • ­  Dimensions, tensile, hardness, threads, recess, head marking to AN, MS, NAS, NASM standard
  • ­   Magnetic permeability to test specs ASTM A342
  • ­  Quality Assurance to procurement spec FF-S-92 MIL-STD 1312
  • ­  Inspection system requirements per Mil-I-45208
  • ­  Full lot traceability, manufacturer’s certification and chemical and physical certification
  • ­  Available in diameters from #0 through 1/4 inch in coarse and fine thread and various lengths

 

Features of a 4-40 x 3/8 Commercial Phillips Flat 100 degree Machine screws in 18-8 series stainless steel:

  • ­ Manufactured per ASME B18.6.3-2002
  • ­ Thread dimensions to ASME B1.1

 

As you can see, the Mil-spec version is held to a higher and more exacting level of quality and testing than the commercial version. As such, the Mil-spec parts are cleaned and passivated, and tested for magnetic permeability, whereas the commercial parts are not.

 

5.   What level of certification is required?

Generally, a Certificate of Conformance (COC) or a record affirming a fastener has met the requirements of the relevant specification, contract or regulation is sufficient for Mil-Spec fasteners. Full certifications, which include the part name, part description, date of manufacture, lot number, chemical composition of material, and treatment of material including plating or passivation, and material test reports, are often available for a fee. It is critical to ask for the level of certification (COC, full material certs, passivation certs, etc) in advance in order to have the most efficient buying experience.

6. Are there other factors to consider when procuring Mil-spec fasteners?

Great question! Almost a decade ago, the term “DFARS Compliant Material” came to the forefront for companies supplying parts and services to the government. The original Federal Acquisition Regulation (FAR) clause 252.225-7014 specified “A Preference for Domestic Specialty Metals.” What that means in our world is that for fasteners to be DFARS compliant, the metal used to fabricate them must be melted or manufactured in the United States or a qualifying country.

Qualifying countries include: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Egypt, Finland, France, Germany, Greece, Israel, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, United Kingdom of Great Britain and Northern Ireland.

Important Note: DFARS only pertains to fasteners made from “specialty metals” including: stainless steel, high alloy steel like Grade-BD, or Grade 5 Chromium steel with high chromium content.

To keep up to date with DFARs requirements, visit www.acq.osd.mil/dpap/dars/dfarspgi/current/index.html

  1. Where can I find a list of Mil-spec fasteners and specs?

The Defense Logistics agency is a great resource. They maintain a comprehensive database of specifications and drawings. They also maintain a catalog of hardware that includes NIINs and NSNs that sometimes called out in a bill of materials. Check out the following links for more comprehensive information regarding hardware:

http://www.dla.mil/TroopSupport/IndustrialHardware/  – to view catalogs of mil-spec parts and specs by category

http://quicksearch.dla.mil/qsSearch.aspx   – To look up a specific part

http://www.mfsupply.com/mil-spec-fasteners-s/1823.htm – To see MF Supply’s Mil-Spec fastener stock

http://www.mfsupply.com/v/vspfiles/assets/images/MFSUPPLY_MILITARY.pdf – To download MF Supply’s Mil-spec line card

 

For more detailed information about Mil-Spec parts, to request a Mil-Spec 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 robin@mfsupply.com with your questions, comments or helpful hints!


Standoffs and Spacers Buyer’s Guide

standoffs and spacers mf supply

7 things you need to know

According to the dictionary, a standoff is defined as “a stalemate or a deadlock between two equally matched opponents and a spacer is a piece of material used to maintain space between 2 things.   In the world of precision manufacturing, standoffs and spacers are mechanical components that are used the create space or join parts together, typically in PC boards.  Below are 7 things to know to have the most efficient buying process.

  1. What are spacers and standoffs?

Often classified as Electronic or Panel Hardware, Standoffs and Spacers are commonly used to mechanically support and electrically connect and position components within assemblies, typically in PC boards and instrument panels.

  1. What’s the difference between a standoff and a spacer?

Both standoffs and spacers have a hex or round shaped body, and 2 openings.  The main difference is that spacers are unthreaded with an inside clearance hole, and standoffs are threaded on both ends.  Threads may be male (external) r female (internal).

  1. Who uses standoffs and spacers?

Look inside an assembled circuit board, and you will be greeted by a bevy of Standoffs and Spacers, because in the world of Electronic Hardware, they are the standard for connecting and mounting circuit boards, panels, doors, and gears. Both are commonly used to properly position parts within an assembly, to reduce component contact, to elevate stacked sections, to ensure enough room for heat to dissipate, and to separate or create space between two objects. These guys are workhorses!

  1. What materials and platings are available?

Common materials include aluminum, brass, plastic/nylon and stainless steel. Common platings include clear anodized, nickel, gold iridite and zinc plated. There are over 20 common platings available! Here is a guide to most common materials:

  • Aluminumis popular because of its ratio of weight to strength. It is light, non-magnetic, performs well in severe temperatures, and has insulating properties.
  • Brassis used in making high-quality standoffs. It is conductive, resists corrosion, and is non-magnetic. It is costlier and heavier than aluminum and is usually plated zinc or nickel.
  • 18-8 Stainless Steelis strong, conductive, nonmagnetic and offers excellent corrosion resistance.
  • Nylon 6/6is superlight, nonconductive, and resistant to chemicals and solvents.

316 stainless steel, alloy and other exotic materials, and special diameters and lengths are available in certain sizes and/or for special order and usually involve a lead time.

  1. What sizes are available off the shelf?

Standard stock sizes run from 3/16 – 1/2 body diameter, 1/4 to 2” long with threads starting at 2-56 running through 1/4-20 and clearance holes ranging from #2 though 1/4”. Metric stock sizes run from M3.5-M6 body diameter with M2.5, M3 and M4 threads.  Remember, the lengths and threads available depend upon the diameter of the body and not all size configurations will be available.

As always, special lengths and sizes are available – just ask!

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

The easiest way to order is by manufacturer part number.  If you don’t have one, you’ll need to specify body diameter, body shape (hex or round), body length, thread size & gender (male or female), material and plating.  For example, a popular standoff size is a 1/4 hex x 1/2 Long x 10-32 male Standoff in Stainless Steel.

  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.  Popular brands include: Amatom, Concord, Globe, H.H. Smith, Lyn-tron, Microplastics, Keystone, Pem, RAF, Unicorp.

Finally, standoffs and spacers sometimes show up under their Mil-spec numbers, which can be crossed to commercial equivalents. Some common Mil-spec series include NAS42, NAS43, NAS61, NAS1056, NAS1057, NAS1829, NAS1831. Where applicable, these Mil-spec parts will be DFAR compliant with full paperwork.

Contact me at robin@mfsupply.com 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 http://blog.mfsupply.com/

To request a Custom Quote, email yout print to sales@mfsupply.com

 

 

 


Socket Head Cap Screw Buyer’s Guide

7 Things to Know When Buying Socket Head Cap Screws

Socket head cap screws or socket caps, have become the standard among high-strength fasteners needed to withstand the faster speeds and higher pressure of today’s machines, instruments and assemblies.

Also known as their trademarked name, “Allen” screws, these fasteners are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more. Common uses include machine parts, die fixtures and assemblies.

1. What is a Socket Head Cap Screw? 

Socket caps are externally threaded cap screws with a cylindrical head with a flat chamfered top and a hexagonal recess for internal wrenching. Hence, socket caps need less space than alternative fasteners.

Whereas nearly 90% of all commercial and industrial fasteners have a 2A fit, which offers a combination of performance, economy, and convenience, socket products generally have a 3A thread fit. 3A threads have restrictive tolerances often used where safety is a critical design consideration.

Because of their efficient design and thread fit, socket cap screws are ideal for precision assembly work with close tolerances and applications that need a well-tooled appearance.

2. What sizes are available?

Commercial socket caps, which conform to ASME B18.3, are available off the shelf in inch sizes starting as small as 0-80 diameter and are commonly available to diameter 1-1/2-6. Metric socket caps, which conform to DIN 912, are available from M1.4 – M48 diameter and are most common in coarse thread. Screw lengths and thread lengths are related to the diameter of the screws and all lengths may not be available in all materials and styles.

3. What materials and platings are available?

“Steel” socket caps off the shelf are alloy steel black oxide through heat treatment and are generally oiled. Stainless steel grades 18-8/303, A2, 316 and A4 are also commonly available. Other exotic materials such as brass, 416, A286 or special finishes may be available for special order with a lead time.

If you need an alloy steel fastener, but require greater corrosion resistance or a different look than black, consider stainless steel or zinc plating.

4. Are there special considerations when plating socket head cap screws?

We are so glad that you asked! 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.

5. Other than size, material and plating, what other options are available?

The other main considerations when selecting socket caps are the head style and the drive type.

There are four main available head styles, and each serves a slightly different purpose.

  • 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)

Most socket caps come with a standard hexagonal socket drive. Other options include security pin-in-hex, pin-in-torx, or six-lobe torx versions in certain sizes and materials.

6. Are there other factors to consider?

We’ve covered the most common variables including head style, diameter and thread, length, material and plating or finish. Here are a few of the other considerations you might be faced with based on the project and the bill of materials:

  • Do you need domestic parts or will imported screws work?
  • Do you require parts that conform to a specific mil-spec number, such as MS16995, MS16996, NAS1351 and NAS1352 with their exacting tolerances and traceability, or will standard commercial parts work?
  • Does your bill of materials calls out a specific manufacturer, such as Holo-krome or Blue Devil?

7. What level of certification is required?

Generally, a Certificate of Conformance or a COC is sufficient for your customer. Full certification with material certs, DFARS certification and test reports are often available for USA-made and mil-spec parts for a fee.

Socket Head Cap Screws Available at MF Supply

MF Supply is a leading supplier of Socket Head Cap Screws in alloy and stainless steel, including the brands Holo-krome and Blue Devil. We offer functional equivalents to the most popular national brands such as Fastenal, McMaster-Carr, MSC Industrial and Grainger.

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, 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).
  • Mil-spec MS16995, MS16996, NAS1351 and NAS1352.

For more detailed information about socket head cap screws, visit our website. And if you don’t see it 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.

Follow our blog at http://blog.mfsupply.com/