ball scews are really expensive

[Harvid]

Hi I´m a newbi to cnc and this is may first post

And I´m stuned, to see the amounth off nollege from all you in here



My problem is

ball scews are really expensive, and extreemly expensive in danmark (europe)



So I have an idea to use parts from a bi cykle these is more avelerble and a lot cheaper

If I´m using a bicykle chaine and the smallest gear (the small guide gear on the back wheel gear shifter)

around the gear its 13,5cm (the green ring on the drawing) and if I use 1/8 microsteping I will have a travel per step at 0,084mm

I think it will be precise enough for me but will it be power full enough to do it this way ?



The electronics is a Stepmasternc controller with 260 oz motors from

http://www.stepmasternc.com/stepmasternc_010.htm

and planning to build “joe” size routher



I have no idea how fast a steper moter is turning around (RPM) and if its posible to ragulate the speed

And if its is poseble to regulade the speed down, will I get more tourgh



How many cm travlinging per second is idiale for cutting mdf



I just saw this wire driven machine, this solution may even be better…

http://video.google.com/videoplay?do...97521879&q=cnc

how is the wire setup build? does any of you have an idea?



Ideas and thoughts will be highly appriciated

Kind regards Harvid