The linear bearings are chtr. Not sure about the ball screws and nut.
http://m.chtrmotion.com/ball-type-linear-guides/linear-motion-guides.html
They are a knock off of THK brand. If you look up TRH linear bearings that should help you find comparable ones. There two types on these machines. Long and short style. If you look at the bearing look for the print on it that says TRH30...at least that is what is on mine.