Bob, I have found a couple of formulas for calculating the length of the pendulum and the answer is between 12 and 13 inches. One thing that concerns me is that none of the sources I’ve found talk about the weight of the rod or the bob. I was using a 1/4 inch dowl to simulate the pendulum and I cut a slot into the top of the dowl and slid it over the end of a new suspesion spring that I cut to the same length as the original. I tried different weights for the bob but none of them has as yet worked. I am about to order a pendulum of the correct length from Timesavers. Their tech guy suggested the one I am ordering. I’m not sure how to post a photo in the forum, so I will send you an e-mail with the photo. This movement has really been abused. One of the main springs was completely broken, two of the wheels were bent and several teeth had to be straightened. The arbor for T-1 was loosened from the wheel and I am in the process of trying to rerivet the wheel back to the arbor. If you have any suggestions about that I would be all ears. Thanks for your help.