Routercnc - Thanks for that. The latest soluton allows for the screw nut to travel between the rails which keeps the overhang to a minimum. Apparently I still have a bit more work to do on that.:whistling:

Chip - I realise it may be a bit belt and braces but what I have learnt so far is that strength is paramount. The back plate will assit in the end supports and reduce any rotaional force on the boxes....maybe

Thanks for the comments guys

Bruce

Forgot to mention i order the cabling. I dare not order any other materials as there is still time for a few more designs.