I want to build my own custom micro crawler but I'm having trouble making U joints. Ive been playing with various sizes of brass and copper tubing for the past 2 hours and the smallest U joint Ive made so far has a diameter of about 9 mm around the biggest part, when I try to go smaller the drill bits destroy the tubing or skate too much. I know TTTTs have smaller U joints but Im having trouble finding english sites that have any info on them. If you have any sites or techniques to share I would be gratefull. -- HWS