Don't use MDF for that part, maybe something like a block of CLS, which ever way you do it you are going to have to be extremely accurate with your sizes.
Leadscrews well from the little I have learned you need a certain amount of speed regardless of how slow you would like to go. So it is possible you will get some sort of whipping with a 10mm leadscrew, don't forget the minor diameter will be less than that, other thing is that I couldn't see any angular contact bearings with a 10mm inside diameter.