Hi All - Thanks Keon, "Sharing" the term was invented by the alcoholics anonymous organisation and it has filtered out into the community. So after a restless night thinking through these machines... I've decided to go with the lifting gantry. The C frame machine would be simpler but the lifting gantry is scalable to large machines which I'm interested in and I want a lifting router and a lifting mill in the fleet. The size of the current machine is driven by the package size of the bearings so I'm going to drop to 15mm bearings. I also don't like the look of these monster columns sitting on two bearings so I'll do the twin rails in 15mm for the columns but single rails for the gantry. I'll also drop back to 12mm for the ballscrews...So I'll go through my CAD library and check what I have in this suite of parts and start rebuilding... Keep making Peter