old toy cap for connection

I had this toy when I was a boy, now my mom lets my nephew play with it, but it is missing a coulple of these end caps .. so I was tasked with this , after having shown some promise of making broken things to my brother !
This is a ruff draft so have a draft as you wait for the final version !
The pic of the hand holding the part is of the original, not a printed version.
* Printed the 1st one and it was way too small, design started without really measuring ,also the printer was flaking o