decisions decisions etc - I opened the column model and in simsolid converted everything to steel . The model then weighed 998kg I placed a 1000N push load on it and it deflected 16um (62N/um). I did the same for Milli No4 and it weight just over 1000kg so same mass coincedently. The 1000N deflected it 37um so maybe the moving column is the G-O. I realise its early days and I can fiddle with geometry and stuff. But I'm up for heaps of time to get this to the point of making swarf so want to maximise the success/time ratio. So I think the moving column is the go and I can make it a little longer with no losing stiffness. Plus being my first mill it needs to be simple... Peter