This ring gear has been designed to fit on the Canon EF-S 18-55mm F3.5-5.6 IS kit lens, the budget lens that can come with the Canon Rebel Ti2/550D DSLR camera. I designed it for my own needs as I could not find a supplier that made one to fit this lens. It has two gear types, the standard 0.8 Mod, which should work with a standard follow focus, and a lego pitch gear for those like me who can’t afford or justify spending cash on the real thing.
I had my ring gear printed in Alumide and I found it fitted the lens like a glove, I’ve not tested any other materials yet so keep that in mind if you order one. You will have to supply your own bolt/screw to fix the ring in place but you will need to open the hole to suit. It does not require much pressure to hold it in place, I fact I only used an 8.1 x 1.6 mm o-ring to hold it in place.