Posted by Nigel Graham 2 on 21/08/2022 15:49:51:
That branch with the screw-plug suggests to me that it is the inlet, with an oiling-point; the exhaust perhaps on the other side.
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Could be. I agree it's the inlet but wonder if the side thingy is a crude throttle, where tightening that set-screw blocks the input.
Possibly hand-made and early. Seems to be made of Copper apart from the brass inlet which looks manufactured and out of character. Identifying the threads might help, especially if they turn out to be non-standard. I'd love to know exactly how the valves work.
Judging by the finish it was made by an advanced Learner, or possibly it's a proof of concept. Good enough workmanship to run, but far from Exhibition standard. Looks like one of mine!
Dave