I don't have a sig or a file to attach...other than 13 minutes of me dial-gaging bits of 5/16-18 threaded rod in MP4 to get some SPC on my build.
I'm building a Unimat One RepStrap called Bateson; is the name taken?
5/16-18 or M8 threaded rod fits nicely in the spindle bore of a Unimat One.
Aside from that...it's a cube, Darwin / Sakura style, and it's minimal--the leadscrews are structural during assembly and supported later.
It can print its own side panels at 115% scale, and so, in 5 generations, can be twice the size.
Doug