Cap for Nema 17 Adapter

I made this little cap for the Nema17 adapter for the 28BYJ-48 Stepper motor by szalat ( https://www.thingiverse.com/thing:2218916 ). This little adapter is great but in a couple of projects, I found that the ring around the spindle does sometimes for some projects acts like a support or centering positioner. This adapter lacks that, so I made this little cap.

The cap was made on Sketchup (2014), so it is not a prefect circle. I added the files in case somebody wants to improve on it with a C