Thanks JAZZ that's all really useful to know.

The nema 23 inside the gantry is bolted face on to a plate that uses a screw to adjust the tension and another to lock it off so I would imagine bolting straight through with m6 tapped frame in the motor will work well there.

As for the z that will probably be the m5 (with head modified if needs) as the design calls for it to be bolted to the mount rather than the other way round.

Hopefully I can get the gantry built over November if work allows and then have December to get the frame cut and welded up for the base.

I have not put any feet on the frame design and was thinking about sitting it on a concrete pad in the garage that I will run some levelling screws over. Does this sound like an ok base for a machine like this? I will be bolted down ideally which is why I'd rather it was as level as poss to avoid distortion to the frame

Or should I bolt it down as I weld it up?