I remember my mum smacking me round the back of the head saying I didn't need my hands to look, but it certainly helps (the hands not the smacking). Have you found any that are still workable? Whatever it screws into has to be thin because of the space between the threads and that main block thingy.
I've got a sneaky feeling someone out there is laughing at us and rolling around on the floor. If you are please put me out of my misery. WHAT IS IT?????