At last, I have 3D printed an adapter to attach an angled viewfinter to the polar telescope finder. This is for the Star Adventurer polar telescope, but I think it fit even others.
My document of how I did it:
http://www.astrofriend.eu/3d-printin...r-adapter.html
It works so perfect compare to my film canister build adapter. This is my first real 3D printed product I will use so I have great times.
/Lars