Good morning folks, I am just getting going on building a Terrier 5" gauge using the Martin Evans drawings, i have seen a couple of warnings about them to note. I have a specific question, the steam chest shows a couple of 1/2" x 40 TPI threads on the underside, any idea what they are for? Not having an assemble or part-assembly drawing I am not sure of their purpose. Can anyone help please? Thanks, Phil.