Hi Geck - Its fine to modify ballscrews with a machinist that knows how to do it. But why? If you plan the machine and get the parts, confirm the part dims then order the granite what's the difference? Heaps, you haven't had to mod anything and the machine ends up exactly off the dwg board. I used different (aluminium) motor mounts on my last machine. The supplier said they were identical to my usual steel ones. But the dwg supplied had a conflict on it so I waited until the mounts arrived. They were 5mm longer than "usual" If I'd committed to them I'd have to shorten my ballscrews, But since I now had them in hand I could make the wall 5mm longer and everything was kosher.. Peter

By the way when your figuring out working lengths of ballscrews you loss about 12mm due to the heads of the nut mounts or the motor mounts if you don't include them in the model. So if your trying to get accurate working lengths include the screws so you can pick up the clashes...