I've been battling this for about 2 years now...any thoughts would be welcome. Herschede Tubular Bell movement has an intermediate wheel with 4 lifting pins. The lifting pin contacts the lifting lever on the 1/4, 1/2, 3/4, and full hour. The point where the pin meets the lifting lever changes making the lifting lever move more (and be a more difficult load) as the hourly progression proceeds...hence the 1/4 hour lift is the shortest and the easiest while the hour lift is the longest and most difficult. When the clock hangs up, the hour lifting pin is trying to lift the lifting lever but can't. This prevents the intermediate wheel from turning and stops the time train. Once "hung" most any movement or vibration (stomp your feet hard) will get the movement out of its bind and the clock will run if the pendulum is started. Typically, it will run for a month or so then hang. If freed up and restarted it will only run for a day or two before hanging again. At this point I've been removing the lifting lever, cleaning it, buffing it where it contacts the lifting pin, and putting things back together. After this, the clock will run for another month. The lifting lever is now so smooth I can't imaging any more buffing does anything, but it still seems to make the clock run for another month, and then hang. The time train weight is also some how involved as it never hangs when the weights are lower than 1/2 and most always fails within a day or two of winding. The long lever that the lifting lever lifts seems to be working right and not presenting a too heavy load.