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


Volume 12  

December 17, 2014

What the heck is that fastener?

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

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

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

Cage Nut

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

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

Mil-spec DFARS

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

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

Wire Insert

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

Wire inserts are used for 3 main reasons: 1) to repair damaged threads in parts that would otherwise have to be scrapped; 2) to strengthen threads against failures due to stripping, seizing or corrosion; 3) to convert threads between inch and metric sizes.

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

Standoffs and Spacers

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

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

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

Precision Shoulder Screws

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

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

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

Dowel Pins

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

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

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

Retaining Rings

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

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

Common brands are Rotor-Clip and Waldes,Truarc.

Keensert® Key-locking insert

The Key-locking threaded insert is a solid bushing style insert that is threaded on both the inside and the outside, and has wedges or “keys” attached to the top of the insert.

Generally, Key-locking inserts are used to distribute loads and strengthen or repair threads against failures due to stripping, seizing or corrosion.  Key-locking inserts are commonly used in high torque and high temperature situations, and in applications where fasteners may be repeatedly removed and reassembled.

 Set screws

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

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

And that’s all she wrote……

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

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

Warm Regards,


The Screw Lady

One Comment on “What the heck is that fastener? The year in review – 2014.”

  1. I had no idea that the acronym DFARS refers to the materials used in military fasteners. It’s really interesting that the Department of Defense has strict requirements for even the nuts and bolts used in their equipment. I bet that anyone in the manufacturing industry would look to find something that meets these requirements because then they can be confident in their quality.

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