Hi John,
Ive worked on several versions of these, large and small, and I’m guessing yours is the small (bullet shaped pendulum weights). So it sounds like your already onto the issue. If that shaft shorts this may be the issue of hanging up. They’ve always referenced a glass tube but honestly never seen 1! My guess is the original double arm (never touched one of these!) model. Or it’s the insulator between the inner shaft & outer portion that rotates within the tube.
Several critical issues are 1. the height of the silver pin on the suspension spring, as once the pin contacts the slide it can’t touch it again until the next swing. 2. The spring does serve a critical role as it ensures the contact returns to completely down once released by the contact pin.
I’m not sure which copper wire your referring to as there’s several? No, you shouldn’t oil the shaft passing through the tube. The fiber washer won’t keep the movement energized as your describing. My suspicion is either the coiled spring is deforming and touching the plate grounding and holding the circuit or the silver pin isn’t locking?
Basic circuit goes positive (it really doesn’t matter, just easier to follow) to behind dial to resistor, to coil spring then passes through the center (insulated) to the outer portion of the slide (has a ridge) and is insulated from the locking portion of the contact slide. The silver pin on the suspension spring is the ground completing the circuit. The reason for connecting the other wire to the top of the suspension is to ensure a good completion of the circuit.
I‘m thinking you might want to run the clock with the dial off al watch the spring for possibly touching the plate. The last is showing the correlation of the slide contact and how it electrically functions. The screw is holding the 2 pieces together with an insulator both between the screw and plates.