Purchasing a z-axis?

[Gary]

This looks like one of mine?
If so this is the details, and it is mm pitch.

http://www.slidesandballscrews.com/pdf/Machining.pdf

As it turns out its not 400mm, more like 340mm, 230mm usable thread. 16mm diameter at the threaded bit, 10mm shaft, and 6.35 tip. I'll double check that later. Pic attached, with a 300mm ruler next to the screw.