This whole laser rebuilding excercise made me realise how far behind the times i am in terms of 3d. Used to be quite good at it at one point (3dsmax, first couple of versions). Now, using nanocad (as autocad is way too expensive) as it is the most accurate representation of autocad CLI, but still sucks compared to actual autocad.
I dont do well in point'n'click interfaces, i strongly prefer command line interfaces.

I usually do the usual engineers 2d plane/section drawings, then if there is a need model it.

In this particular case i need to re-engineer whole Y motion without actual capability to measure physical box it has to fit in. Too tight, welded, measuring tools dont fit. So i resorted to drawing out as much as i can, laser cut metal parts in different thicknesses to make up a sandwitch that best fits the gap in the machine, then either recut proper thickness or weld the sandwitch together, etc, etc... Bit of a bodge, no way around it...

If i were to buy another chinese laser, i woundnt. I'd just build one from scratch. Easier that way... Whole "buying chinese laser" thing is an ongoing nightmare and money sink.

I also learned that UK consumer protection laws suck and i'd have been better buying over ebay for protection, than buying from local UK importer...

Sorry for the rant... bad day...