I actually just got done making a very small first run try at a 3 axis machine. Bearings and screws seemed to work wonderfully. I now have a pair of bearings and screws which may work good for you. They are 37 inch long 1" dia , 4 turns per inch,route
Maybe you would like to take a look . I have posted all the information that I thought I needed to use them. But it was just going to be to big of a project.
Item number: 3804800919
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3804800919