About the Seth Thomas “Mark I Deck” Clock
Title: Seth Thomas Mark I Deck Clock: A Collector’s Treasure
The Seth Thomas Mark I Deck Clock, a timeless masterpiece from the renowned American clock manufacturer, is a mantel clock of unparalleled elegance and craftsmanship. Produced between the late 1870s and the early 1900s, this model represents a significant period in the evolution of Seth Thomas’s clockmaking artistry.
The Mark I Deck Clock is distinguished by its elegant case design, typically crafted from high-quality mahogany or walnut. The rectangular case features a flat top with a glass cover, creating an open view of the intricate mechanical workings within. The base is often decorated with ornate carvings, adding to the clock’s aesthetic appeal.
What makes the Seth Thomas Mark I Deck Clock a coveted collector’s item is its blend of traditional craftsmanship and innovative design. This model was one of the first to feature a detachable rear movement, making it easier for repairs or maintenance without dismantling the entire clock. Additionally, the Mark I Deck Clock boasts an eight-day timekeeper with a striking mechanism that produces a distinctive, melodious chime on every hour.
Notable features of this model include the beautifully crafted Roman numerals and finely detailed pendulum bob visible through the glass top. The clock’s dial is often adorned with intricate brass bezel work, further highlighting its exquisite design. For antique clock collectors seeking a blend of style, functionality, and historical significance, the Seth Thomas Mark I Deck Clock is an invaluable addition to any collection.
Auction Records and Price History
The following 2 auction record(s) show actual sale prices for the Seth Thomas “Mark I Deck” model clock. Prices vary based on condition, originality, and current market demand. Search for more records on AntiqueClocksPriceGuide.com.

C.1940, (dated) Seth Thomas Clock Co., 8-day time U. S. Navy Mark I Deck Clock.
This timepiece has the serial no. 4731. The brass cased timepiece is mounted on a mounting plate and swings out to be wound and set from the rear. The brass case is in very nice condition with some minor roughness from use. The dial is in exceptionally nice condition with original hands. Note luminous paint on hands and 5-minute markers has discolored. Height 8.25 inches
Sold: $300 | Date: 4/26/2003 | Source: R. O. Schmitt Fine Arts

C.1941, Seth Thomas, Mark 1 Boat Clock, U.S. Navy, in good condition.
The dial of this clock carries serial number 4855 and the year ’41. At some point the clock was returned to port of service and another Seth Thomas movement, made a few months later and with serial number 5184, and the year ’42 was installed. These are interesting clocks, hinged to a rear mounting bracket and unlatched and swung out weekly for winding and regulation. Dial diameter 3.5 inches
Sold: $450 | Date: 4/26/2003 | Source: R. O. Schmitt Fine Arts