Dealing with Open Ends: Expert Tips for Fitting Custom-Cut Springs
Introduction When you order a spring cut to a specific length, it arrives with “open ends.” Unlike mass-produced springs that are ground flat in a factory, a custom-cut spring follows the natural pitch of the coil right to the tip. While this allows for bespoke lengths, it requires a slightly different approach to installation to ensure a level seat.
Why Your Spring Might Look Long At Springs and Things, we add a small allowance (typically one coil) to your requested length. We do this because an open-ended spring doesn’t sit “flush.” If we cut it to the precise length of a flat-ended spring, it would sit lower once installed. That extra coil ensures you have the full functional length you need for your machinery.
Three Ways to Seat an Open-End Spring Since flattening high-tensile steel is difficult for most users, here are the professional ways to manage the ends, starting with the simplest:
- The Washer Shim (Easiest for Everyone): If you need the spring to press against a surface, simply place a standard steel washer between the spring and the material. This prevents the open “tip” of the spring from digging into the surface and provides a stable, flat base for the spring to push against.
- The Internal Guide Rod: If the spring is sliding over a shaft or bolt, the flatness of the end matters much less. The rod prevents the spring from buckling, and the open end will naturally find its seat against the shoulder of the shaft or the bolt head.
- The “Step” Method (Best for 3D Prints/CAD): If you are designing a housing, don’t design a flat floor. Instead, design a small “step” or a helical ramp in the base of the hole. This allows the open tip of the spring to “lock” into place, providing a level seat without any modification to the steel.
A Note on Cutting and Safety Our smaller spring sizes can be trimmed to length relatively easily with a good pair of wire cutters. However, spring steel stores energy. Always wear eye protection when cutting. Cut ends can fly off at high speeds, and the resulting edges are extremely sharp.
For our larger, thicker wire gauges, we do not recommend attempting to cut them at home as they require industrial-grade equipment. If you are unsure which category your spring falls into, please contact us before ordering.