The screw appears to be in excellent shape but the nut is noisy. Who rebuilds these? Or where can I buy a new Y axis screw and nut online?
Don't know what part of the country you are in. We use Express Ball Screw Repair in Cleveland Tennessee (near Chatanooga) Pete Edwards is the guy to talk to 800-711-2153. We have had four screws / nuts rebuilt by them for our Cinci's and are very satified. There are a lot of places that do this, most bearing houses also provide the service.