Inspecting the Mean Time Gears

One of the first things I wanted to check on was the mean time gears. At the end of troubleshooting the clock was stalling consistently with the gears oriented the same way, which suggests that there is friction that varies with the rotation. The immediate theories were runout of some combination of gears and a damaged or miscut tooth.

The first, second, third, and escape arbors were removed from the clock and inspected. For runout, I cobbled together a surface plate setup that suspended the arbor between two jewels just as it would be in the clock. A tenths dial test indicator was used to measure runout of the arbor immediately adjacent to the gear to isolate runout due to arbor curvature. This was between 0.0010 and 0.0026 amongst the arbors. The OD of the gear teeth was also indicated for runout. These are shown in the plot below completely, but generally were .001-.004 for pinions and .003-.005 for gears.