Hi HiltonSteve,

Thought I was the only hobbiest CNC bloke in Derby! I have built a few machines and currently use my largest for profiling/machining 10mm Aluminium. I changed the design several times mostly the Z axis as I need it to be as rigid as hell.

I used 20mm fully supported rail (THK) similar to the Hiwin rail it has a key shaped profile. It can take massive loads.

I used 10mm od ball screw with a 3mm pitch which with my 23 frame motors gives me a max speed of about 2000mm per min (not that fast but fast enough for a machine 600mm x 300mm).

Your welcome to have a look if it would be of any help as your nice and local. I could also point out where I went wong! I also have a small lathe so could turn down your screws if needed.

Something else to consider (depending on the accuracy you need) would be Trapezoidal leed screw. I use this on another machine and made my own nuts out of both delrin and PTFE, Its good to approx 0.05mm. It is also very cheap, 10x2mm is 80p per 100mm and I already have a Tap to make nuts.

Mike.