Comments sought on new build: A CNC Router for RC Gliders and Planes

[njhussey]

OK Dean, switched the gantry around again to how it was before. Have put a folded aluminium enclosure over the Z axis, on the bottom of the Z there will be a rubber cover (5mm thick rubber with cut outs for the rails) to stop chips going up into the bearings. Have put deflectors on the X axis to stop chips hitting the linear rail, also put a deflector down the bottom so chips slide into the bin. Have altered the ballscrew mounting so it's on 20mm block and not the aluminium box section as I'm not using that anymore. I will also put a cover over the X axis belt and steppers.

Couple of questions now...

1. I'm going to use 1 stepper and belt (T5, 15mm wide) and pulleys to drive the X axis, what number teeth pulleys would you recommend? I take it that it's worth getting spare pulleys and belts so that the option of 1:1 and 1:2 (stepper to ballscrew) is available?
2. For the belt idlers/tensioners I was going to use skate bearings (as I've got sh*t loads of them) and penny washers, I couldn't see any specific idlers for the belts?