Ah, that’s because it’s not listed. Oversight. Rev 03 it is!
Anyway, it is just (in the US anyway) plain-old “1/4-20 All Thread” (1/4″ diameter, 20 threads-per-inch). Like this: http://goo.gl/4vbSUD. Though you will need a 4 foot length for the X-axis.
You could use any size and thread pitch, tho if you go larger than 1/4″ diameter, you will need different bearings. For your neck of the woods, you might have better luck with a metric version. Just size your bearings to match and Bob’s your uncle. Thread pitch is adjusted in your CAM setup software (# of revolutions per inch or equivalent). Good nuff?
Good eye! Thanks.
I knew about Dwg 1011 (updated version attached).
I’ll look into 1027 – I just started re-reviewing the plans to add the 1011 revised drawing and anything else that made sense.