They've been lying around the bench for a while but I was sure to have to take them apart from the thing a few times, so I've waited until complete achievement of the work.
It's for sure some furniture stuff made in UK or USA as the distance between the holes is exactly 5 inches, so for a 36 inches lens, that's going to use 4 x 5 inches sheet films, it's perfect.
You can see on the picture a very rare thing in France : a ruler with inches ! (my workshop is rich).
It gives a more professional look, and it's much more convenient to handle the lens when I want to put it on the tripod or to take it away.
From the opposite side, it has another important use : when triggering the lens, the right hand pushes the brass screw in the center down, and even if the release has became very soft, it might give a little movement to the lens, also, it's good to have the left hand far away from the mechanism that's quite fast and coud be armful if a finger is in a wrong position.
The workshop benches are a mess after all this, after cleaning, these are all the remains of the project.
I had a big mystery in the beginning : one of the hinges had lost it's rod, maybe the poor quality of the stuff, and the shocks of the blade mechanism. Anyway I had another one, so I've changed it. And I finally found the lost rod in the dust.