Good deal, Alan! Sometimes, when things 'don't seem to work right', if we'll simply step back and examine what we have to work with closely, the 'solution' often comes to us. Someone mentioning "a tab on the fork and a slot in the housing" was the 'key' you needed in this case, and illustrates one of the things this site is best known for - helpfulness!

The voyage of discovery that truly matters is not in seeking new lands but in seeing with new eyes.