Awhile back there was a need for the above but I don't remember where the request was posted or which radio needed it.   Perhaps it was for a project?

I have found several NOS couplers (still in individual sealed bags) made by Western Electric for some type of test set.  Ceramic is 1 inch in diameter, a smidge under 3/4 inch end to end.  The coupler accepts a 1/4 inch diameter shaft.

$10 each plus shipping in a flat rate padded envelope, several available, please contact me off list if interested.

Regards,

Jim