Retaining Rings: An Instant Shoulder for Your Components

Sometimes modifying an assembly with a convenient, affordable “add-on” part just makes more sense than making your machining operations even more complex than they already are. For instance, if you need to create a shoulder on a shaft or inside a bore, you have to use more total material and spend extra machining the shoulder, both of which will cost your business extra money. It can be a lot cheaper and easier to fit the shoulder on as a separate piece. So here at Mr. Metric we offer internal and external retaining rings for just that purpose.

A retaining ring is a ring-shaped piece stamped out of spring steel — well, almost ring-shaped, because one small part of the circumference is left open-ended, with the metal ends flaring into little loop-shaped lugs. The two basic types of retaining rings include internal retaining rings and external retaining rings. As for the difference between the two, the name pretty much says it all — an internal retaining ring slips into a groove within the bore of a shaft, while an external retaining ring fits onto a similar groove in the shaft’s outer surface. The lugs on each end of the ring open opening flare slightly, and when released they cling firmly against the groove to prevent rattling or instability. Once seated into the groove, the retaining ring serves as a shoulder for attaching various components to the shaft. And a retaining ring requires no specially threaded surfaces or access holes, unlike bolts and other fasteners.

Metric Retaining Rings

You’ll find retaining rings — sometimes listed as snap rings, spiral rings, retainer clips and other self-explanatory names — in components spanning practically all industries, including agriculture, automotive manufacturing, photography equipment and construction tools. And you’ll find the perfect ring for your needs at Mr. Metric!

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Mr. Metric is the spokesperson for, an online store for metric fasteners. Get $7.50 flat shipping with no minimum orders, plus advice and best practices for using metric fasteners in any application.

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