While the X axis on the mini mill has ball thrust bearings, the Y axis doesn't, with the leadscrew and hand wheel riding directly on the housing. This really increases the friction in the system and makes the hand wheel harder and less smooth to turn. Unfortunately, there isn't a lot of space to install a bearing. However, Phenom Engineering made custom low profile bearings which work in the restricted space, and a custom Teflon washer for the shoulder of the leadscrew itself to ride on. Installation was very easy and straight forward, and the difference is very noticeable. I highly recommend this kit.