Lower wishbone to hub carrier

Hi

I've repaired my flexi's and I've refitting everything except the lower wishbone ball joint that goes into the hub carrier. The new nuts are quite tight and the ball joint thread just keeps spinning. Has anyone got any advice on getting the taper to bind into the wishbone? Its driving me mad!
 
use a long bar to lever it up to stop it spinning or a small scissor jack & block of wood under it
 
In the tip of the wishbone's ball joint thread you can hold a hex bit with a ratchet, then use a ring spanner to tighten the nut. The hex is easy to round off so be careful and take it slow.