I wrote before about the Timesavers 15959 clock mainspring, specified as 3/4 by 0.0165 by 120 inches. My latest batch of these springs are different: they have a copper rivet and the loop is formed from the spring itself (i.e., not a separate piece). Also, the spring is thinner, the one I used is 0.0153 inch thick, which is plenty strong enough for many antique American clocks. I used it for the time mainspring in a Sessions black mantel clock.
Below are photos of variations on the 15959 mainspring I have received:
- Left: 0.0145 inch thick, labeled 37 on the loop;
- Center: 0.0165 inch thick, labeled 42 on the loop;
- Right: 0.0153 in thick (only one example measured so far), copper rivet.
- Bottom row: A Sessions black mantel clock in which I installed the 15959 mainspring with copper rivet. I installed the spring in the time train, and it provides plenty of power.
Repair job 5921. Installed 14 bushings, replaced the damaged time mainspring (Timesavers 15959 with copper rivet, 0.00153 inch thick), re-pinned one pinion, replaced the click on the time mainwheel. The original time mainspring was 0.0176 inch thick (but the replacement needs to be thinner). The original strike mainspring is 0.172 inch thick.
The clock is 10 7/16 inches tall and 18 inches wide. The minute hand is 2 1/8 inches long.