I'm retired now, I must have retrofitted 10-20 of this model. I don't know if they all have the same ball screws, I'm guessing most of these models do and are now in someone's garage or pole building. Anyways, be aware they have one of the best name balls screws in them, however the ball nut is a double nut about 6"+ long and is fixed very rigidly to the saddle. They have a narrow saddle so if your Gibbs are not snugged up, the table flops around a little bit, and it squashes the spacer between the 2 nuts. KEEP THE GIBBS FAIRLY SNUG or this will happen to you. When's the last time you checked the Gibbs? Cheers, Bill