This ad is posted here solely for the graphics, I think it would be perfect for a modern T shirt.
Be that as it may, William Mills Foundry was started in the 1890s, and soon added aluminum casting to its business. The company produced aircraft engine parts during WW1 and expanding into pressure diecasting in the 1920s when iron casting was discontinued. During WW2 they once again were a large supplier of aircraft parts. After the war they continued supplying castings to the automobile and airplane industries. The company seems to have disappeared some time in the seventies.