Ok, so there comes a time in every CNC builders life where he realises that threaded rod was ok for the first few months, but now it needs some proper ball screw.

So it is with some major reluctance that I blow the cobwebs off my CNC 'kitty' tin & delve inside to find the minimal amount sloshing about.

Firstly, I'd rather not upgrade my mill's end supports (which are SK16 ... http://tinyurl.com/ygk4stf ...these in turn hold some bearings with an ID of 8mm) ...esle this is gonna get very costly.

So to my first question, bearing in mind I have simple needs, my X Axis is about 400mm, my Y Axis is about 300mm ...(I'm not touching my Z axis for now) which would be the most suitable ballscrew for integrating into my present CNC mill (would simple trapezoidal type threaded rod be a better option ...if so which pre made nuts to use ....I've turned my back onnthe DIY nut route - life's for living, not making nuts!)

Next, I have a Sieg Mini Lathe & an ER32 collet chuck/collet set - would it be possible to use this machine the rods ends down to the aformentioned 8mm diameter?

Many thanks for any input - Hank.