Expert: William J Perkins - 8/25/2008

Question
I recently acquired a common New Haven store regulator clock called the Referee. The movement is marked 9 3/4. I am trying to install a standard 4 1/2" bob pendulum. It just keeps running to slow and I can't go any shorter on the rod length. I think the movement may be a replacement New Haven out of a short drop regulator using the small 2 1/4 pendulum bob. My question is what does the 9 3/4 number on my clock movement mean? Thank you very much for any answer!!!!!

Answer
I have long ago donated most of my former technical library to various horological schools and orginizations, ergo, when I respond to questions such as these it is from memory and not technical sources.  If memory serves me correctly the 9 3/4 refers to the plate size.  Also if memory serves me correctly your clock should be about 3 ft long, which would indeed call for the long pendulum, probably not the 4 1/2" bob though.  Due to the performance you describe I would very carefully examine all the pivots and their holes.  I suspect there is a friction problem involved.  I know this probably is not of much help, but it is an opinion built upon having faced theis same problem many times before and the most common cause relating thereto.