Melv, most machine tools that I have worked with have a better finish than this and usually just an oiled surface not painted, but thanks for trying to everyone .
The lip around the edge looks like there should be an upper casing the seals the unit given that the thing that looked like a handle is a spigot then it could well be it is filled with fluid when assembled. I am now more inclined towards some kind of pressure control mechanism.
It looks to me like the bit that sticks out to the right can be pushed inwards (to the left) against the strong spring, so the spring is there to keep that bit pushed formly outwards.
I thought that the central pice should move forward tensioning the spring. The ends of the central piece are held in a clamp that does not show signs of movement under it therefore the whole central part would have to pivot on the lower part of the clamp resulting in the movement being an arc.
I fear that unless someone actually knows what it is then I will never know however I do not give in easily and have now got the bug.
The bit on top looks like it will move very slightly left against the spring, as there are two pivot points which will rock as the top, pushed by the bit sticking out to the right as it tries to move leftwards. There will only be a very small amount of movement, which makes me think it it designed to keep the stick-out bit engaged with something else.
The mystery object has a handle, that suggests to me it has to be attached and removed quickly.
I'm now thinking it's part of a machine that mass produces components. Could be armaments?
Like Naomi I have subscribed to the thread. I have been furiously searching the sales and auction sites but have found nothing like it. I think that once Donny gets his hands on it he will be able to come up with a theory. The cast work certainly looks early 20th century. Wonder if it was for shaping or bending metal.