From the best of my knowledge, the QOCs were installed sometime around 1974 give or take a year.
So far I have not been unable to find any information regarding Thor(n)hill Craver other than their involvement in manufacturing chokes.
I am trying to do some research to find the specific o-ring sizes for our various QOCs (quick opening closures). So far I have identified Tube-Turn and Huber-Yale as two manufacturers within the plant, but one manufacturer remains unknown. The only information still visible on the unknown QOCs...
