How to measure & install tension springs

Tension springs are often found on mid century chairs and they are very easy to replace. Here's some helpful hints on replacing tension springs yourself at home.

• Tension springs are often found on mid century chairs both on the seat and/or on the back. 

• Sometimes the tension springs are installed in rows, and sometimes they will be installed in a diamond style pattern.

• Each tension spring has a "hook" at each end, which is attached to a clip, eyelet, trunk plate or bracket on the frame. 

• Under normal conditions, tension springs are approx 10% smaller that the frame span so that the spring stretches across. However, to make it firmer use a shorter spring. To make is softer, use a longer spring. 

• Tension springs can be cut to a custom size by using bolt cutters, or a disc grinder. A new hook can be bent from a spring round using pliers. 

• For a tight seat (ie: foam and fabric is stapled onto the frame) cover the springs with hessian before adding the foam.

• For a loose seat (ie: you have loose cushion seating), cover the springs with quilted lining. Tension springs are measured from 'inside the hook' to 'inside the hook'.