Motor Couplers

Hi,

My home converted mill uses belt drives to connect the motors to the
ballscrews. I am trying to motorise a dividing head by directly coupling the
motor to the wormshaft. So far my home made attempts have all suffered from
alignment problems. What I want is a coupler that allows for some
misalignment of the two shafts and has no (well minimal) backlash.What do
people use? If homemade what is the design? If not homemade what type of
commercial couplers work well in this application.

Thanks,

Dave Micklethwaite.