Sometimes you’ve been standing at a stripped shaft, wondering about that stubborn metal ring that won’t hold in place. Perhaps it popped out when you torqued on the last bolt. Maybe it didn’t even fit with the groove. E-clips are among most misunderstood fasteners out there. They look simple and is easily done incorrectly. You’ll often be back to square one fixing the goof.
A quick reference is found in chart above which breaks down both metric and imperial standards. It explains relationship between ring thickness, groove depth and shaft diameter. Keep your clips in labeled bins by shaft size.
How to Use E-Clips Correctly
Axial Retention That’s where the trick begins. A snap ring (E-clip) fits over a shaft that has been pre-machined with a groove for it to fit in. It stops part from sliding sideways along the shaft. Bearings have to spin and remain in place, and gears does too. By gripping side walls of the groove, the clip retains it.
For the small ones, you don’t need special pliers. Simply push it on. When it clicks, you know it’s done. That click is both satisfying and a warning. If it didn’t seated flush, it won’t later.
Many people don’t realize that choosing the right material are key. For dry indoor use, they’re typically made from zinc plated carbon steel. They have light load strength and an affordable price. The zinc layer is very thin and will vanish quickly around salt air and water.
If you want slightly less thrust but better protection from corrosion, use stainless steel grade such as 304 or 302. Where magnetic properties is an issue, phosphor bronze takes over as the standard material. It is non-sparking and has good electrical conductivity. This can be a life saver when relying on non-metallic properties.
Most projects fail due off the geometry of the groove. The groove should be smaller in diameter then the shaft itself. That gives the clip something to stretch when snapping into place. That stretching create the holding force. Too small a groove (too narrow) and you’ll never get the clip seated properly. Too large and the clip just rocks and then pops out with the load.
The reference guide shows those size relationships for both inch and millimeter standards. It’s a great way for engineers to exactly match the hardware. A caliper comes in handy here. Measure twice, save hours of frustration later.
How you install them matters too. They have to be straight-on over the groove and then pressed on. If they are not straight-on, they will bend metal out of shape permanently. That greatly reduces their holding power. On small ones less than a quarter-inch, just use your thumb or some other flat thing like a screwdriver bit. With larger ones, use a tool so you apply equal pressure across the entire clip.
Remove using eye protection. A tight spring clip will come flying off surprisingly fast. Do not ever try to reuse one from a critical application once it’s been removed. The metal has permanently changed shape and lost its strength. You should of avoided this.
Another thing often left out is storage. When assembling, mixing sizes can be expensive. Label bins and keep your clips separated by their shaft size. Moisture also ruins carbon steel, so store it in air-tight containers with desiccant packs. This helps prevent surface rust. Corroded clips will have lost much of their gripping strength before you install them.
A careful choice and storage routine transform this delicate part into a trustworthy fastener. It is a small detail, but it is significant. That horseshoe-shaped ring holds things together securely… If done correctly and the right size are chosen.
