Hi All - Moved the bearing and ran the model, then ran it without the support bearing... Answer 1.08mm with bearing, 1.05mm without. So at the bottom position seems the support bearing is a not needed. Hmmmm will have to set up a couple of models at 25% 50% 75% extension to see whats happening. But its all happening at the 0.01mm area so maybe chasing tissue paper. Move onto finalising drawings for quotes better time spent. Peter