Your fastener distributor offers a wide variety of fasteners for every application. From a corrosion-resistant stainless steel hex bolt to a selection of dependable rackmount screws, this industry professional has what you need. But what about those special circumstances where a standard fit won’t cut it? What are the different types of locking fasteners available? […]

Your fastener distributor offers a wide variety of fasteners for every application. From a corrosion-resistant stainless steel hex bolt to a selection of dependable rackmount screws, this industry professional has what you need. But what about those special circumstances where a standard fit won’t cut it? What are the different types of locking fasteners available?
There are two basic types of locking fasteners available, prevailing torque and free spinning. Not all locking fasteners can be reused, so if your application requires repeated loosening and tightening be sure to choose a reusable design.

Free Spinning Fasteners
This type of locking fastener will turn or spin without a problem until it begins to seat. Any tightening that occurs after that point activates the lock. The design of free spinning fasteners includes flexible components that cause the initial piece to deform and grip the joint surface. Teeth or ridges are the most common design features, which dig or bite into the surface to lock in place.
A free spinning fastener may be reused, but it will not create an equally tight hold the second time around unless the surface changes. Often this type of fastener is permanently deformed upon tightening - the original form will not return after the fastener is loosened.
Prevailing Torque Nuts
Prevailing torque nuts use resistance to provide a lock on the mating threads. Ask your fastener distributor about the benefits of using all metal prevailing torque nuts, although you'll also find plastic and nylons products in the catalog.
Certain designs of this fastener are reusable, but only those that include a spring back mechanism or design. That motion allows the locking feature to be activated time and time again. Some prevailing torque nuts actually damage the mating threads to create a lock. That is irrevocable.
Adhesives and Chemicals
Some fasteners use glue, resin or epoxy to create a lock. Adhesives can also be applied separately to bond fasteners together or attach fasteners to the material. This type of locking method cannot be reused and should only be applied in places where moisture and environmental conditions do not break down the adhesive.
If you have an application where locking fasteners are required, ask your fastener distributor to point out the best option. Depending on the conditions and long-term requirements, you may choose a free spinning type or opt for the prevailing torque design.

About the Author

Larry Melone
By Larry Melone
President

Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.

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