Quote Originally Posted by Karl View Post
Just out of curiosity, is there a rule-of-thumb for whether and when to use 5mm or 10mm pitch ballscrew when constructing an XYZ table (for routing mainly hardwoods)?
It depends on numerous factors. 10mm pitch gets you much better speed and acceleration, but unless you use pulleys (which you really should...) you clearly have half the resolution of a 5mm pitch screw. If the axis is quite long you'll certainly want a 10mm pitch screw, since because the screw pitch is greater the rpm for a given feedrate is less so the screw will not whip until twice the feedrate it would with 5mm pitch. For a short axis, like Z, whipping isn't a problem so 5mm is fine. In most cases on a 'reasonable size' router 10mm pitch with pulleys is the way to go for X and Y and choose the pulley ratio depending on what your're cutting (to favour resolution for speed).

However clearly there will always be exceptions and each case is different, so you need to read up on it, decide and calculate for yourself.