This Waterbury tambour mantel clock was made around 1920. The movement plates are steel that have been given a thin brass plating. Brass bushings were inserted in the plates so that the pivots (steel gear shafts) can turn in brass holes as usual (steel on steel would cause severe wear).
This clock strikes the hours and half-hours on a heavy coil gong. The case is 17 1/8 inches wide and 9 3/4 inches tall. The dial’s minute track is 4 3/8 inch diameter, and the minute hand is 2 1/4 inches from center to tip. The video below shows the clock striking:
When the clock arrived in my shop, the finish had been stripped from the case. I stained it with brown mahogany gel stain, and finished it with spray semi-gloss Deft lacquer.
This movement is a good example of an American clock movement with weak mainsprings. The springs are open (no barrel), 3/4 inch wide, 0.014 inch thick, and about 8 feet long. Many American movements have stronger springs (0.0165 – 0.018 inch thick). A 0.018 inch thick mainspring provides over twice the force of a 0.014 inch thick spring (because the force is proportional to the thickness cubed).
This movement has a strip deadbeat escapement with a very small escape arc (the minimum swing needed for the clock to tick). The running arc is over 3 times the escape arc, showing that the thin springs provide plenty of power for this movement. Unfortunately, it is difficult to find weak enough springs if replacements are necessary. Springs that are too strong will cause wear. The video below shows a closeup of the escapement, and shows the amount of pendulum swing, starting from the minimum:
Repair job 5675.
Last updated: 2012/01/20