This appears to be a gimballed compass, probably with geared indicators to allow more accurate readings.

Modeller Tone Source Shipyard Plans for HMS Acheron (1911) from the National Maritime Museum Grid Size 1 mm Scale 1/48 This fitting could doubtless be improved by a better drawing. For one thing, I omitted the calibrating iron/steel spheres that should be on either side, like ears. It is difficult to tell if all fittings of the same size/function would be of the exact same design. I am not sure whether brass would have been used throughout. Perhaps some rivets on the bottom sealing ring would be good, but I omitted them for simplicity and since I did not know a good shape or count for them. This item would likely be brass.

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