Siff' Build Log

[everyreasonto]

Thanks for the input guys, I really appreciate it. I hadn't seen the seller linearmotionbearings before.. boy is he cheap! I'm really liking the look of the machine you posted Jonathan but wouldn't I need two ballscrews and two steppers on the X axis?. looks like I could get a larger machine for the same budget, using the supported rails that everyone seems to be suggesting from linearmotionbearings. The rails I put in the original plan were 16mm so I guess I overestimated their strength.

Budget is my only constraint, excluding spindle, I have about £1000 to spend.

Taking advice on the stepper drivers, I've found some from a seller called cnc4you. I also intend to get my steppers and ballscrews from there.

EDIT: Looks like i'm going to go for this set: http://www.ebay.co.uk/itm/3-SBR20-se...#ht_1004wt_948. Would work out around £450 shipped (inc tax) and they are all 20mm rails.
It would fit very nicely to the 60x30 profile from hepcomotion.

I'm going to make a point of avoiding Valuframe extrusion because they said that delivery would be £33 + VAT if they were sending to a private address, robbing gits!

[Jonathan]

I hadn't seen the seller linearmotionbearings before.. boy is he cheap!

When you've decided what lengths of ballscrew and rail you want send him a message with the sizes and he will list them on eBay.

I'm really liking the look of the machine you posted Jonathan but wouldn't I need two ballscrews and two steppers on the X axis?.

Yes you would - it's the best way to do it anyway. You could link the two ballscrews with a timing belt and just use one stepper motor. Another way is to use cables beneath the gantry (like on a drawing board ruler) to link the two sides...

There's more about it in my build log, probably just read the last few pages!
http://www.mycncuk.com/forums/showth...outer-building...
Also here for more pictures, though this isn't neccecary for the size of your machine.
http://www.mycncuk.com/forums/showth...t-design-ideas

Budget is my only constraint, excluding spindle, I have about £1000 to spend.

Taking advice on the stepper drivers, I've found some from a seller called cnc4you. I also intend to get my steppers and ballscrews from there.

£1000 not including spindle should be plenty...less than I spent.
Get your ballscrews from linearmotionbearings. They will be exactly the same and end machining is very very cheap. Look on eBay for stepper drivers - there's some 80V ones that look tempting, or if not this is what I got because at the time they were not on eBay cheaper:

http://www.zappautomation.co.uk/pm75...71a69c8def8e2f

I also used the 3nm motors...

I think steel box section is much more cost effective than using extrusion. Definitely for the stationary parts where weight isn't an issue.

There's a pdf with all the drawings for the ballscrews/blocks etc in one place here ...
http://www.file-vault.us/pdfs/ball_s...umentation.pdf