Greg,
Have you considered removing the shackles altogether and using a slider?
Here is a hard slider assy:
http://www.secureperformanceorder.com/afcostore/getproduct.cfm?CategoryID=14&ClassID=180&SubclassID=851&ProductID=985
and there are also poly sliders available.
Use a very flat spring...
Good luck with the bandsaw.
The last pair of balljoints I took apart required a grinder to separate. It appears the outer case (at least) was hardened.
Bill
