Seth Thomas “Adamantine” Mantel Clock with “Ding Dong” Strike

Here is a Seth Thomas “Adamantine” clock with black and green marbleized finish (Adamantine is Seth Thomas’ patented celluloid finish that was made in many colors to imitate wood and marble). It strikes the hours on two brass bells, and strikes the half hour on the higher pitched bell. The clock was sold on March 22, 1916 (22 March 1916 is written on the label on the back cover). My customer’s grandparents received this clock as a wedding gift from family members in June 1916.

The case is 18 1/8 inches wide at feet, 11 1/16 inches tall, with 4 1/4 inch time track on dial.

Below is a slideshow of more photos:

Here is a video of the clock striking:

Here is a movie of the escapement action, first run down 7 days, then fully wound:

Repair job 5094. No. 89T 8-day time and bim-bam strike movement.The time mainspring is a 3/4 x 0.0172 x 96 inch mainspring from R & M Imports (opened to 8 inches when unclamped. The time spring was original, but I replaced it because it had a squeaky and jerky action which sometimes indicates it will break soon. This movement needs a slightly stronger time mainspring than the regular No. 89, as the half-hour strike hammer is lifted through a great distance. The strike mainspring is the original (marked ST) 3/4 x 0.0165 inch spring. It opened out to only 6 inches in diameter when uncoiled, yet provides plenty of power to operate the striking for over 8 days.

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  1. I just purchased a Seth Thomas Adamantine ding dong clock on line from a Kansas seller on Mercari. I also was surprised to see the Ding Dong mv’t in this case, as Trans du Ly does not show this model. Everything appears original& the clock functions well.

  2. YOU ARE THE MASTER BILL! i am finding so much info about the antique adamantine I just won at an auction! Hearing about the history of Seth thomas and his clocks is fantastic and clearly you know how to do repairs and remodels -strong work!

  3. This is a great site. I have several old clocks, all very sentimental as my dad collected and/or inherited them. Thanks for so much great info.

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