Rubinar focuser mechanism is now without backlash as well.. I used those
nylon hose clamps to attach the springs..This solution of the problem is even better than what I used for MTO, it is certainly cheaper and easier to do - no need for machined parts.
Also, this design offers very interesting possibility for focus motorisation, since those clamps, when tightened around the tube could be used as worm gear...
This may well become the next phase of this little project..