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I recently repaired the movement of this Seth Thomas 8-day OG shelf clock.

Before repair, the clock would run for several minutes and then stop. While running, it would go in and out of beat (the ticking would sometimes be even and sometimes uneven).

The movement was taken apart and cleaned. The major problem was that some of the escape wheel teeth were non-uniform. I used the Webster escape wheel tooth straightener to ensure that all the teeth were at the same angle. The wheel was mounted in the lathe and the teeth bought to a uniform height, then the burrs were removed. The pallets were polished, the worn pinion wires in the escape wheel pinion were replaced, the pivots polished, and bushings installed in the worn pivot holes.

The following video shows the escapement action before and after repair:

The following video shows the movement in the case and shows the hour striking:

It is possible that the movement is not original to the case. We suspect this for two reasons:

• The pendulum bob is quite low in the case;
• The end of the center arbor touches the glass when the door is closed.

The movement is labeled “Plymouth” which means that it was made in 1865 or earlier when the town where Seth Thomas was located had the name “Plymouth Hollow”. It 1865 the town name was changed to Thomaston to honor Mr. Thomas. The case label says “Thomaston” so this could be a transition clock made around 1865, or it could be a later case with a older movement. The reverse painted glass is not original to the case, it appears to be a New Haven multicolored glass.

The weights are replacements, weighing as follows:

• Time weight: 8 pounds 1 ounce
• Strike weight: 6 pounds 9 ounces

Repair job 5064.

Related posts:

1. Seth Thomas 8 Day Four Sided Top Shelf Clock
2. Seth Thomas Cottage Clock with 8-Day Lyre Movement
3. Seth Thomas Mahogany Adamantine clock, 4830
4. Early Seth Thomas Brass Movement OG Clock
5. Seth Thomas Oak Kitchen Clock with 89E Movement
6. Mainsprings for Seth Thomas Queen Anne, Time and Strike, with Second Hand

I recently repaired a Seth Thomas Adamantine mantel clock made around 1905. It has a No. 89 movement. This movement is very efficient in operation, due to the use of a deadbeat escapement. Even with a thin time mainspring, these movements typically take an excellent escapement motion.

This particular example has thin, original mainsprings.

Time Mainspring: 3/4 x 0.0167 inch.

Strike mainspring: 3/4 x 0.0163 inch. (Unfortunately, I had to replace the strike mainspring because it had a rough action when nearly wound, typical of springs that may break soon. I used a new Merritt’s Antiques P-1956).

Many examples of the No. 89 movement have thicker springs, quite often around 0.0175 inch thick, sometimes thicker. After proper repair, this movement will run well with thin springs.

Here is a video of the escapement motion, first run down 6 1/2 days, then fully wound:

Repair Job. 4970.

Related posts:

1. Mainsprings for Seth Thomas Adamantine, 89C Movement
2. Seth Thomas Mahogany Adamantine Mantel Clock
3. Seth Thomas Adamantine
4. Seth Thomas Mahogany Adamantine clock, 4830
5. Seth Thomas Adamantine Clock
6. Seth Thomas “Adamantine” Mantel Clock with “Ding Dong” Strike