I'm not even sure whether I'm using M10 or M8. I bought some M8 rod from Screwfix...it was woeful wrt being straight (& it's going back!)

I figured going up a notch in diameter might help on the straightness, but I'm still wavering on the extra work (friction) it'll cause my feeble steppers (taken from discarded dot matrix printers)

Just to put you in the picture...this will be my first CNC build. The plans are in my head...it'll be an evolution...it'll also be rather small (mainly because I have 6 free steel rods - with bushings- that are only 12" in length).

I'm aiming to do this as low cost as possible (as I'm sure to make mistakes), build 2 - if I ever get there - will be when I throw a bit more money at it. Looking at your blocks they seem a little small in comparison to the ones cheekymonkey linked to...I'd envisaged using blocks a little larger (just to spread the connectivity points wider into the table base).

With the above in mind, I'd be grateful for anyviews on..

1. M8 vs M10 rod.
2. Whether it matters one tot going stainless steel vs zinc plated steel.
3. Whether one delrin block or more is used per axis ...if so, is it better to use slightly larger blocks or not?

I'd already emailed this seller...

http://cgi.ebay.co.uk/ws/eBayISAPI.d...n%3D1%26ps%3D5

As his Delrin block looks like the size I'd envisaged...also because it's dirt cheap (which appeals to the unfeasibly tight side of me)