Sorry for the delayed summary.
Try the McMaster-Carr site:
http://www.mcmaster.com/
They have a lot of 3D models of springs...
Have you looked to this website
(http://www.mcadcentral.com/proe/files/gallery.asp?categoryid=15)? I
have not this specific model. However, I have been pleased with other
fasteners that I have downloaded from this site.
Thanks to all those who replied! I also received a spring similar to
the one on mcadcentral.
I will look through these sites.
Thanks again,
-Tom