Quote Originally Posted by FatFreddie View Post
You could share the X axis rails and ballscrew - you'd just need to bolt the ballnut to the gantry you wanted to use. The plasma gantry would be relatively cheap to build as it doesn't need a powerful motor or high stiffness linear bearings.
Yes I wasn't suggesting that two sets of screws/rails would be needed for the X axis. Good point about not needing high stiffness bearings...what about these:

http://uk.rs-online.com/web/search/s...duct&R=4485499

They're rated for high speeds, and cheap...


Quote Originally Posted by FatFreddie View Post
One consideration would be choosing an X axis stepper that had the torque for routing and the speed for the plasma but you could always gear it and swap the sprockets over.
Yes I think having a pulley/timing belt on the X axis is a must. Thinking about it if you had pulleys on all the axis then perhaps one could get the machine fast enough with the milling gantry since it could, with a bit of experimentation, be geared for much higher speeds since you no longer care about cutting force.