Hovering over "Buy"... care to sanity check my thinking?!

[brumster]

Not much replies to questions, which is fine we're all busy people, so I wonder whether this now needs moving to a new build thread? Would that make more sense? I'm not saying it's definitely going to happen yet but maybe that will get it better visibility....?

I made a start on the design anyway, made some assumptions....



80x40x4 steel box welded frame, X on the platform and a fixed gantry (Y and Z), single central C5 ballscrew, external size 600x500. BGR15 linear rail (why not), NEMA23 motor, big design question at the moment is direct drive or pulleys/belts? I know some of you seem to be fans of pulleys/belts; any reason to go that route? I don't need it for the gearing-down/accuracy as by my measure, even direct will give me the resolution I need (and microstepping, even better). Are there other good reasons to belt-drive?

Appreciate it needs bracing...

I need to get some ballscrew dimensions to understand how the motor/linkage needs to be spaced... when you spec a ballscrew are the "unscrewed" parts of the ends always a fixed dimension or will it vary from one manufacturer to another? I took a quick look at one datasheet I found but there were no dimensions on there (from Zapp Automation). CNC4YOU have some specs up for C7 ballscrews but would my C5's be any different?