Nice work on this. I took me a bit of tinkering to get the number of perimeters right. I broke off the ends of the cylinder on my first try but reprinted it with more perimeters I used 5 with a .6 nozzle. Here are pictures of the one just finished and the first one already mounted and in use. Just a tip for others who might have problems getting it to fit on the wheels and the inserted in the guide a little bit of beeswax makes it fit perfectly. I printed standing up as you can see and it works just make sure you get the walls/perimeters high enough to add strength to the ends that insert in to the wheels.