I was at the flea market, and spotted this buried at the bottom of a box of random tools. I was able to see “Athol, Mass,” so it came home. ID-ed it as a No10 Patent Inclinometer. It was frozen, but today with WD40 and gentle taps with the handle of an electricians screwdriver, I got it apart.
Trouble began when the wind (it was a beautiful day, so I was working outdoors in the sunlight) blew away the paper plate I was putting parts on, but a big magnet helped locate the two tiny retaining screws in the gravel where I was working on it. I eschewed the paper plate after that.
I believe there is a missing element, possibly a ball bearing. I do not recall seeing it fall, and it didn’t grab onto the magnet when I was recovering the screws.
The threaded hole (A) that the protractor set screw (A1) goes in is slightly deeper than the screw, so it does not contact the inside of the protractor, and the counterbore is wider than the threads. The screw was bent midshaft so it wouldn’t thread in all the way, so I wrapped the threads in paper, put it in a vise and gave it a couple taps with a brass hammer. It still may be slightly askew (or the threads are lightly deformed where the bend was, but it does thread in with a little resistance midway.
Interestingly, it was not in the configuration (degrees on the same side as the slot in the rule) shown in the catalog as found, and it will not go together that way, unless I file the tip of the blade retaining screw (B1), because the recess (B) for the anti-swivel tab on the screw isn’t machined deep enough on one side. But also, the indicator mark on the frame that lines up with the degrees is only present on one side of the frame, so this IS the way it was made.
I used a brass brush to remove dried spermaceti oil and light rust, and put it back together as found. I’ll probably try adding a ball bearing so the protractor will lock.
