Knex Micro Coaster Quick Swap Base

I made this so that you can easily attach and detach different coaster cars/covers to you micro Knex coaster cars. There is not much micro Knex items out there so i decided to make my own. This is just the base and i will be coming out with covers shortly. I am semi-new to 3d modeling so it is not perfect, and some of the bases do look bad but i am still trying. In order to bolt on the cars to the base, i used a Bemaka M3 Screw Kit. Feel free to make your own cars just make them as a remix so other people can enjoy them.