The first thing to do when making a purchase is to select all of the bolts and screws that come with the kit. They are complete rubbish; They took it off before I could tighten them. It was almost comical. I've just looked in the Guinness Book of World Records and unfortunately there isn't a category for "Smallest Linear Bearings That Can Be Physically Produced" but I'm sure if they did they would take first place. They're only a fraction of the size of a tiny ball of solder that you can brush off the PCB you're about to finish working on. Very impressive. The lead screw and clutches are great.