T-Mount adapters - any trick to these?

[Hektor]

I recently bought a Tamron macro zoom(it came with the XD11 body and standard lens) But for some reason the adaptal -2 mount will not click on properly on the Tamron lens. The mount came in the original box and is marked MD so it should be the correct one. The instructions are there, but try as I might it will not mount correctly so the aperture ring can turn.
Thanks, John

 

[Garbz]

Click? My T-Mount stuff is a threaded connection so I'm not entirely sure on what the issue is.

But one thing to check, is there a difference between the T-mount and a T2? I haven't looked much into it since I only ever needed the one adapter to get everything on my telescope and it's 2" thread from there...