John, Here are some pictures of the inside of the pendulum's cast brass shell and the discs that were inside of it. The bottom two discs are steel (one is used as the bottom cover), the next two discs are brass, and the last disc is copper. Note that the inside surface of the cast brass shell is inscribed with the movement serial number. Also, the two brass discs are stamped with the numbers 2055 and 1248. A number.40 suspension spring was put in the clock yesterday afternoon and it ran approx. 16 hours, gaining only 5 minutes, before being stopped to inspect the inside of the pendulum this morning. So it seems like it will be easy enough to get it regulated now. Thanks again for the information that you and Eric have provided. Pat L.
The time gain is essentially 1/3 of a minute per hour, or about 20 seconds per minute. Pretty fast. You will need a thinner spring on the order of 0.0035 or 0.0036 inches. Note that each 0.0001" represents about 4 seconds per minute. Kurt
Pat, Quite often extra discs are added to bring a clock in time with the suspension springs that are available. In it's original form, your pendulum would not have had any extra weight and would have had a smooth cover held in place by a lip just inside its edge. https://mb.nawcc.org/attachments/pendulum-1-jpg.273005/ Eric
John, This pendulum, 21996, is not consistent with any other Crown pendulum I've seen or recorded. The disc itself is too thick and matches the other gallery style discs in its number range. I would say this is a marriage of two pendulums. Eric
I know this is an old post, but the suspension bracket in question here was used by JUF with their "PA" and "DRP" movements, and when they started numbering their movements again. See this post: Seeking info: Urania 400-day clock with disc pendulum and this one: Jahresuhrenfabrik Angemeldet Clock Info required The highest number I've recorded with this bracket is JUF 53182. Eric
