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FAQ Section


  • What exactly is a retaining ring?

    Definition: A fastener that holds components/assemblies onto a shaft or in a housing/bore when installed in a groove.


  • Why should I use a retaining ring instead of a screw, nut and threads, cotter pin and washer and other traditional fasteners?

    Retaining rings can do the same job for a lot less. A simple groove is all that's needed to accommodate a retaining ring. Other fastener methods, like nuts, require machining threads, which is a lot more costly. They also require at least two components to function (Ex. Cotter pin and washer, nut and washer), which adds to the costs.

  • I don't think retaining rings are strong enough for my application. Aren't they for light loads only?

    This is one of the most common myths about retaining rings. Retaining rings are used on everything from ABS brakes to mechanisms to adjust the tank tread on an M1 tank. You'd be amazed at the holding power some types of rings exhibit.

  • How do you install retaining rings?

    That depends on the application, but you can be sure there is a tool for every retaining ring we sell. No need to use fingers, hammers, screwdrivers or other tools that may damage the ring and cause it to fail. We support our retaining rings with a complete line of manual and pneumatic tools. We'll even help you design your own equipment for high volume assembly.

  • Should I design my own custom retaining ring instead of relying on a standard one?

    Selecting a standard retaining ring will always be more cost effective than designing a custom retaining ring. It will also save on engineering time, eliminate production problems and ensure timely delivery of product. A Rotor Clip technical sales engineer can help you find a suitable standard replacement for a custom retaining ring.

  • When would you use an inverted retaining ring (HOI or SHI)?

    Let's say you have another assembly that must pass through the housing of your application. Check the Clearance Diameters "L1" and "L2" dimensions. This will tell you if the lugs of the ring will interfere with this assembly. If this is the case, you can switch the ring to an HOI (HOusing Inverted) (or SHI SHaft Inverted for a shaft application). This ring features inverted lugs for better clearance.

  • When do you use an axial (installed horizontally) versus a radial (installed vertically along the radius of a circle) retaining ring?

    If your application can accept either an axial or a radial retaining ring, shoulder size, thrust load and RPM may determine which type you use. Be sure to check these specifications carefully before making your selection. (Keep in mind that radial rings offer enlarged shoulder for part retention and generally cost less than standard axial rings).

  • I am using an E ring, but it is not strong enough for my application. Do I have to scrap the shafts I have and start over?

    If you select an E ring and later discover that it can not withstand the RPM generated by your application, you can change it to a standard, heavy duty RE ring. RE rings fit into the same grooves as E rings and can be easily interchanged without re-designing the application. They can accommodate higher thrust loads.

  • Why are there so many different E ring designations in your catalog?

    The "E" ring specification pages in the Rotor Clip catalog list many variations. For example, E-18, SE-18, YE-18 and ZE-18 are not "specials" but simply different parts that can be used on the same shaft size. They will function in applications having either different groove diameters/groove depths for the same size shaft (3/16"). They also offer optional geometry for a specific shaft size. Often, the O.D., ring thickness and groove dimensions vary for SE, YE and ZE part numbers.

  • What is the difference between a PO and a POL ring?

    This ring series offers a similar advantage as the E and RE. The PO is complemented by a "light" series known as POL that is thinner than the standard PO rings.

  • When would I use an SHR over an SH retaining ring?

    An SHR is a heavy-duty version of an SH ring with increased thickness and minimum/maximum sections that will give you increased thrust load and RPM limits. Keep in mind that an SHR requires a wider groove than an SH before you make the switch.

  • Why are some of your ring designations repeated in your catalog?

    Some retaining rings are listed twice in the catalog (Ex. HO-156). This means that the same ring will function in two separate applications that have different housing/shaft and groove sizes.

  • What are some common measurements for retaining rings that I should be aware of?

    Free Diameter, Axial Rings This dimension can only be measured accurately on rings that have never been installed. Measuring free diameter on an HO ring where the lugs have been compressed (or on an SH ring where they have been expanded) will yield a false reading. Free Diameter, E Rings---Do not take this measurement on an E ring using a caliper. The correct way is to use a pin gauge that makes three-point contact with the ring's prongs. Free Diameter, Inverted Rings The standard way of measuring free diameter for an axial ring does not hold true for an HOI and SHI retaining ring. For the correct method, see the HOI and SHI specification pages in the Rotor Clip catalog. Hardness To check hardness effectively, you must first remove any finishes from both sides of the ring. Using a properly calibrated hardness tester, take a reading on the ring with the burr side up. Compare results to those listed in the hardness tables of the catalog specification page for that ring.

  • What are typical installation considerations for retaining rings?
  • An external axial ring (SH, SHI, etc.) can be over expanded during installation. To prevent this, take a pin gauge 1% larger than the nominal shaft diameter of your application. Using a Rotor Clip retaining ring plier and safety goggles, expand the ring and release it on the gauge. With the tips still in the lugs, adjust the stop on the plier to this opened condition.


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