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

[brumster]

Oh, and spindle run-out, I forgot that. Best I can make out from reading, the usual spindles have a mixed bag in terms of specs and it's probably just a case of cross my fingers and hope I don't get a Friday one...?

I've started designing anyway; when I get it to somewhere sensible I'll share for comment...

What are the merits for move the platform and fixing the gantry on the X, versus fixed platform and moving gantry? It strikes me the moving platform will be easier to design and construct but I'll have to accept a larger keep-clear space at the sides of the machine?

[JAZZCNC]

Basically, £1500 on an over-specced DIY build the same size as a 6040 (but obviously better quality).... or spend £900 on a 6040, use it for a year or two, accept it's limitations, fix it as needed, then flog it on for £400 and consider it a learning exercise... or salvage it for the spindle if nothing else :)

Better Still spend £1500 use it for Two yrs hassle free and then sell it for £2000.!!. . . . .Make a Proper Job using correct components and that is perfectly feasible.

[brumster]

Aye, true :)

[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?