Thanks Ross, that version loads fine
I have added a couple of lengths of 40mm aluminium extrusion to the model

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I have one small problem of the unsupported rails being 30mm too short
I may need to move the X Axis rails on top of the box section to give me a bit more room to play with

I think the biggest problem you will have is the bounce caused by vibration. but that can be sorted by not letting the torch travel at resonant frequencies and keeping the acceleration and deceleration down.
One thing I want from the new machine is to keep the speed up on corners etc
My current machine has a really heavy steel gantry (I originally built is as a Router), and I have to keep the acceleration and speeds down on corners.
On straight sections it cuts parts to almost LASER Quality, when the machine has to slow down for corners it causes dross to build up on the corners :cry:

Andy