I am starting to design the gantry and after reading the other build logs I think i will use Linear hiwin rails HGR20 or should i use HGR15 for the z axis?This is probably a stupid question but what is the difference between a HGH20CA carriage and a HGH20HA and could someone please confirm if the height off the carriage sitting on the rail is 30mm.Do you think I can use one ball screw on the Y axis or should i go with two? All advice much appreciated,
Cheers Greg