End Cones for torsion springs

[cooperjer]

I'm currently working on finding a stronger and tougher end cone for torsion springs. Presently my design is using the overhead door standard of a cast aluminum part. These are about the best parts for the cost, but it seems they have a tendency to crack in our application. Is there a stronger and/or tougher design on the market for winding a torsion spring? More specifically I would need a part that fits a 2.0-in torsion spring and can work with loads as high as 55 to 60 ft-lbs torque.

If you have any leads please let me know.

Thank you,

Cooperjer
Mechanical Engineer