Quote Originally Posted by mike os View Post
more questions..... have I got this right?

ballscrew sizes... fixed & floating bearing for mounts (BK & BF?)
x axis approx. 1000mm between bearings, 20mm screw, 5mm pitch, critical speed about 2000rpm = 10m/min?
Y axis approx. 780mm between bearings, 16mm screw, 5mm pitch, critical speed in excess of 3000rpm=15+m/min
z axis approx. 400mm between bearings, 12mm screw.. critical speed<6000rpm

does this look ok?
It probably would be Ok with 16mm screws all round but in general for wood 10mm pitch would be used for x and y and 5mm pitch for Z ..Clive