How many know what these tools are and how to use them. They used to be very important in the plumbing and steam fitting trades. They are resurfacing tools used to resurface the seats of valves. Not the valves sold today, but some of the old ones may well be around. The valves I'm talking about came apart, the stem was opened as far as it would go, then the top of the valve body was unscrewed and the stem was removed from the top. This tool was then inserted into the valve top and the top was screwed back on the body. The cutting surface of the tool then rested on the seat (of course the right sized tool for the valve had to be selected). The spring applied the correct tension and the tool was turned to redress the valve seat. Often an old style brace was used. The cutting surface (bottom) of these tools is very sharp and they are made of high quality steel. Don't see these very often.