Number of Turns in Torsion Springs

Torsion Spring Design Resources – Spring Design

The number of active turns in a torsion spring is equal to the number of body turns, plus a contribution from the ends. For straight torsion ends, this contribution is equal to 1/3 of the moment arms and is usually expressed as an equivalent number of turns:

Ne = (L1 + L2) / 3∏D

L1 = length of the moment arm of the first end

L2 = length of the moment arm of the second end

Na = Nb + Ne

Nb = number of body turns

Content Copyright Spring Manufacturers Institute, Inc.

This information is attributed to, and provided courtesy of, the Spring Manufacturers Institute, Inc. (SMI). Newcomb Spring and SMI provide this as advisory information only, and disclaim any and all liability of any kind for the use, application or adaption of material published on this web site.