Many of the cabs Hillcraft used were made by a company that also made buttons. The cabochons were made for Hillcraft without the button shank.
Hillcraft was an Indiana company that operated from the late 1940s to the mid 1980s. Their jewelry is unique in its settings which are hand wired, and its earring backs, which often slide on the ear. Much of their jewelry was made by patients of the Indiana State TB sanitarium.
I purchased vintage new old stock beads and cabochons from the last owner of Hillcraft
This set was missing one side of the clasp, so I replaced it with a new spring clasp. I also replaced the earring backs and polished the gold wire. Now it's pretty enough for a bride.
I found a great site with the history of Hillcraft here:
http://www.hoppersbazaar.com/JJ/jj.html