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!

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  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

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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.

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!