Christmas Tree Joiner / shim

Busted a Christmas tree when it was blown over this year.
I discovered it was simply a small plastic "joiner" between the metal sections, so I set about designing a new one - 20 min later here we are!

You may like to scale this to suit your needs. The base is 17mm, the square hole is 11mm, and the inner round hole is 8mm.

The upper section is 8mm Hole, 10.75mm on the square, and should fit right into the lower section.

Inventor and autocad source available on request.