Redesigned Music Wire Extension Spring for the Automotive Industry

Automotive Music Wire Extension Spring (click on thumbnail to enlarge)

To solve the problem of breaking extension hooks, Maverick Spring Makers Limited redesigned the Music Wire Extension Spring. The initial design featured a hook radius that was equivalent to the body radius, which resulted in excessive bending stresses in the hook when it was at full deflection, and ultimately premature hook failure. To redesign the Extension Spring, Maverick Spring Makers created a smaller hook radius to reduce bending stress and to eliminate premature fatigue failure. The reduced hook radius still fit easily into the assembly. For more details about this project or to learn about our other services, please contact Maverick Spring Makers.


Product Name

Redesigned Music Wire Extension Spring for the Automotive Industry


0.059″ Music Wire

Outside Diameter, body

0.862″ +/- 0.005″

Outside Diameter, hooks

0.455″, +/- 0.005″

Total Coils

36.75 +/- 30 degrees

Free Length, Inside Hooks

4.625″, +/- 0.032″

Production Speed

> 400 per hour

Heat Treatment

500 degrees F, 20 minutes, inline conveyor belt oven


Bulk pack in recyclable containers to customer requirements

End Use

Automotive Seat Adjustment Mechanism

Shipped to

Ontario, Canada