With most manufacturing, it is nearly impossible to create an exact match every time. Spring manufacturing is no exception. To keep dimension as uniform as possible, the spring industry has defined acceptable spring tolerances. We can certainly alter these tolerances to meet your unique requirements. Be sure to reach out to our experienced sales team to discuss your needs.
If you have a print, tolerances are the +/- values following a dimension. These +/- figures create an acceptable range for manufacture. The goal is to stay within the given range. For example, say the OD is .500” +/- .010”. This means the OD can range from .490” to .510”. Generally, the larger the spec, the wider the range. Tolerances are given to the wire diameter, OD, overall length, and possibly load. Complex torsion springs may have tolerances on the leg lengths, bend angles, and leg angles. Some prints may call out “box tolerances”. Please be aware these are usually too small and are not accepted by the Spring Manufacturing Institute (SMI). We are happy to let you know the acceptable tolerances.
Here at Jones we follow the SMI guidelines. These tolerances are small, and typically, do not effect general use. With that said, we encourage those with precision projects to discuss tolerances with our sales team. We can help you determine the best spring tolerances for your design. Keep an open mind. Some tolerances are not feasible. Extremely small ranges can mean long production times and higher costs. At the end of the day we all want the same thing, a spring that fits your needs and your wallet. Please contact us for more information about spring tolerances.