Print upside down.

The supplied STL has a hole for the original rotational switch with diameter 6.2, which tapers slightly to give it a snug fit. If you need the hole a little larger, copy the workspace and change the supplied variable.

https://cad.onshape.com/documents/4a11d6ff423752a75c540196/w/088b9c16fe5a080828a71f74/e/c9536fb05f546a285d5a9aa9