William, can you explain to me why and how the 25mm screws didn't work as good as the Hiwin retrofit. I understand that the 25 mm screws are smaller compare to the Hiwin retrofit but if both systems have the same backlash on the same BP, the precision should be the same. At least this is what I understood. I really want to convert my BP into CNC at the lower possible cost (I'm cheap). I'm new to this milling machine world, I started last year when I got my manual BP. I like this tool, it makes me happy. If I have to spend more money to get a Hiwin retrofit, maybe I will, but before I order any parts, I need to better understand what I don't understand. Thanks for your help.