Ingraham “Cosmo Duplex” Tambour Mantel Clock, 1926

I repaired this Ingraham tambour mantel clock, called “Cosmo Duplex”. It may have struck on chime rods at one time, as there are two empty holes in the bottom of the case. Now it has a coil gong. The movement has the date code 7 26 (July 1926). It is an 8-day clock that strikes the hour and half hour. The case is 9.5″ tall and 22 5/16″ wide. The dial’s minute track is 4 5/8″ (to the outside of the minute marks), and the minute hand is 2 3/8″ from center to tip.

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Repair job 6858. I polished the pivots, installed 14 bushings, smoothed the time click, replaced the verge (with an old original in better condition). The old, original mainsprings were 3/4 x .0177 for the time and 3/4 x .018 for the strike. I replaced them with 3/4 x 120″ long mainsprings from R & M Imports (time spring .0158″ thick and strike spring .0164 inch thick). This was back in 2016, today I’d use a 11/16 x .015 x 108 inch mainspring such as the MS298 from Merritt’s.

These Ingraham mantel clock movements are one of my favorites. The deadbeat escapement (strip type) lets it run efficiently with a thin mainspring.

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  1. Hi, great article and nice clock. I have the same movement in my Ingraham clock, but the original pendulum bob was replaced with a lead weight. Could you tell me the weight of the original pendulum?

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