I was wasn't aware that the center of the tire chuck was the valve mechanism. I never thought about it seriously before, but I guess I thought that there was a piece inside chuck that contacted the tip of the valve stem circumference and did it's thing. It is easy to see where extreme industrial application could be different. And of course, the fact that I don't know what I am talking about. But it seems to me I have heard of garage mechanics removing the core before and temporarily filling the tire/tube with air. We're talking decades, here, folk. Old, fragmented...