December 17, 2014
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.
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 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 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 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 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.
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.