Here is a “modern” style Seth Thomas mantel clock made in 1946. It has the newer time and strike clock movement (see my post “1940s Seth Thomas 8 Day Time and Strike Clock Movement” for more details about this movement).
The mahogany case is 14 1/16 inches wide and 8 9/16 inches tall. The minute hand is 2 1/2 inches long.
Repair job 6068. I polished the pivots and installed 17 bushings. The front time main wheel pivot hole was badly worn (see photos). The original strike mainspring, 11/16 inch wide by 0.0185 inch thick, was broken. I moved the original time mainspring (11/16 wide by 0.0180 inch thick) to the strike side. I installed a new time mainspring – 11/16 wide by 0.0163 inch thick by 18 inches long. (The new spring is a CML 175.3 from Mile High Clock Supplies, 11/16 by 96 inches long shortened to 80 inches long.)
Note on mainsprings: When replacing broken mainsprings in this Seth Thomas movement, use a thinner spring than original, to give the movement a longer life. A spring around 0.0160 – 0.0165 inch thick is good.