EF mount wobbly, shimming causes electrical fault, what can I do?

[pipnina]

I got a 300mm f2.8 lens from eBay, but it turns out the mount has a worn locking pin so it can rotate a bit when my astromechanics adapter is fitted, and the adapter is slightly too thin on the mount face leading to wobble (checked with genuine ef camera, rotation is the lens' fault, wobble is the adapters fault)

I was able to use electrical tape around the flange face to provide enough packing (2 layers) to make it a snug fit with no wobble and resistance to rotation... However upon doing so the adapter no longer makes proper electrical connection with the lens! And it cannot control the aperture or focus. Which is very important as this lens cannot be focused manually.

I'm hoping people here might have a good idea or two for me to try, as I really want to try and make this work, and the image I got from it last night (between clouds) showed it is a very sharp lens wide open at aps-c sensor size despite its age and the tilt introduced by the sloppy mount connection.

Thanks for any ideas!

[pipnina]

I have contacted my local London Camera Exchange branch and have arranged to have the lens sent away for mount repair. However even if the lens side is repaired successfully it might still wobble on the adapter as the EF mount camera I have did not wobble but able to rotate due to the worn pin...

 

[Elp]

Can you find a spares camera and replace the mount?

[pipnina]

8 minutes ago, Elp said:

Can you find a spares camera and replace the mount?

Swap the mount on the adapter for a real camera body's mount? I do have an EF mount camera which is scrap so if they fit it's possible.
I got some email back from the Astromechanics guy saying I may be able to adjust it myself but they give no clue as to the electrical solution...

[Elp]

Or you could fashion some sort of copper contact extension, but keeping it in place might be an issue.