Quote Originally Posted by IanS1 View Post
What about the linear guide width, 25mm OK? Bearing distance, there's about 105mm between the ends at the moment. Would you recommend at least doubling that?
when you say 25mm I suppose you mean Rail not carriage width.? If so then yes that will be fine if your using supported round rail but massive overkill if using profiled rails like Hi-wins. 20mm will be fine for profiled, even 15mm will handle far more load than you'll throw at them but 20mm carriages workout easier to use has they larger and suit better.

To be honest the Min/MAX distance for separation on Y axis( Which I call Z axis) will depend on several factors like number and location of ball-screws and rail used. 300mm total bearing plate width will be fine in most cases and less if using profiled rail and twin screws close to the bearings. 200mm will even work if the gantrys strong.

Regards the gantry then you need to seriously beef up this area with bracing. I'd also use wider stronger Cross beams between gantry sides.

Skinning is ok for containing chips and looks etc but wouldn't rely on it for strength and the down side being it's very resonant and you want to avoid resonance if possible.
Stronger base frame work is the best way then skin for cosmetic reason if you feel the need.!