Seth Thomas Adamantine Mantel Clock, Mahogany and Green Marble

Here’s a beautiful Seth Thomas Adamantine mantel clock I repaired. The mahogany-color body contrasts nicely with the green marble color pillars. This 8 day clock strikes the hours on a coil gong, and strikes once each half hour on a brass bell. The clock is 10 11/16 inches tall and 17 3/4 inches wide (at the feet). The minute hand is 2 1/8 inches from center to tip.

The movement is labeled “4 1/2” but was later known as the No. 89. The adjustable pendulum bob is original and weighs 5.4 ounces.

See more pictures.

Repair job 7779. I polished the pivots and installed bushings; unsoldered the fly arbor and smoothed it, adjusted the pallet depth, made new return springs for the warning lever and count lever, and installed a new suspension rod.

The old mainsprings were very strong (0.0185″ thick) and their oil was hard, like dried varnish. I installed two new mainsprings, Merritt’s MS 3/4 x 0.016 x 108 inches.

Note: I repaired this clock several years ago, as of this writing, I recommend even thinner mainsprings, .015 inch thick; and the closest I’ve found is 11/16 x .015 x 108 inches from Merritt’s or Timesavers (3/4″ is the standard width, but 11/16″ works well). If the pivots are smooth and the pivot holes are good, this mainspring gives great results! These mainsprings are from Germany, and tend to be on the strong size, for their thickness. In my experience, the mainsprings from India are not as strong for a given thickness, but also work well when the correct thickness is selected.,

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