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These two “Plymouth” tambour mantel clocks made by Seth Thomas came into my shop just a couple of days apart. They are similar but have different movements. Both have lively hour and half hour strike on two chime rods.

Plymouth was a name that Seth Thomas put on some clocks ca. 1930 – 1950. If anyone has details of this, please let me know.

Our first example is labeled 89IM on the movement. This is a variation on the popular No. 89 movement having hour and half-hour strike, with two hammers that simultaneously strike on two chime rods. The date code is 37-11 which represents November, 1937. The label on the back door has the date 5/21/38 (May 21, 1938) hand written on it. This is probably the date the clock was sold.

Our second example has the later Seth Thomas time and strike movement that was introduced to save on cost. It is labeled 10-40 and 4503, which could be date codes for October 1940 or March, 1945. If anyone can help me interpret these numbers, please let me know! Similar movements have been seen with model number A-200 on them. The label says:

Guarantee and Directions
Covering Clocks Equipped With
4300, 4500 and 4600 Series 8-Day Pendulum
Strike Movements in Tambour Cases

Both cases are 20 inches wide and 9 1/4 inches tall, with bezels measuring approximately 6 1/4 inches outside diameter. Both have “fake inlay” printed on the case front. Both  have aluminum dials. The older dial has embossed numerals, but the numerals on the newer dial are printed only. Both clocks have instruction labels inside the back doors and are illustrated below.

Movement Summary

• The No. 89 movement was introduced about 1900, and was made in many variations.
• It was replaced in the late 1930s or the early 1940s with the second movement shown above. This has smaller plates and gears and was probably a cost reduction. It is not as good, as it seems to need quite strong mainsprings to run well.
• In 1955, a flood badly damaged the Seth Thomas factory. They phased out movement manufacturing and began importing many movements from Germany. They used many Hermle movements.

Related posts:

1. Sessions Tambour Mantel Clock, Made in 1938.
2. Seth Thomas “Sentinel #10″ Tambour Mantel Clock
3. Seth Thomas Tambour Mantel Clock with Enamel Dial
4. Date Codes on Late 1940s Seth Thomas Electric Clocks
5. Seth Thomas Mahogany Adamantine Mantel Clock

Many antique French clock movements are secured in the case by tension: Two screws from the back cover pull on two straps attached to the dial plate. Friction is relied upon to keep the movement secure in the case.

Sometimes the movement may rotate in the case even with the screws securely tightened. This can easily happen when winding the clock. If the movement rotates, the clock will be out of beat (not ticking evenly), and may stop or not run reliably.

One way to secure the movement is to cut 4 thin pieces of double-sided tape (such as carpet tape) and stick them to the edge of the dial pan (where the dial pan presses against the case). The movement must be taken out of the case to do this. Cut the tape to a curved, narrow shape that will not be visible when the movement is installed.

Here are two clocks I just did this to:

Related posts:

1. French Quarter Hour Striking Clock
2. French Slate Mantel Clock
3. Strike warning wheel problems in old French Clock
4. Ingraham Tambour with Quick Release Dial

The Seth Thomas “Helmsman” ship’s bell strike clock has been popular for many years. It was introduced in the late 1950s or early 1960s, and made into the 1980s or longer.

Seth Thomas "Helmsman" ship's bell clock

The Helmsman uses a movement made by Hermle in Germany. The movements made in the 1960s have the patent number 2,974,473 stamped on the back plate. The patent describes a system for doing the ship’s bell strike. See this web page for strike examples. Ship’s bell striking operates on a four hour cycle with pairs of bell strikes on each hour, and pairs of strikes plus a single strike on the half hour:

12:00 XX XX XX XX

12:30 X

1:00 XX

1:30 XX X

2:00 XX XX

2:30 XX XX X

3:00 XX XX XX

3:30 XX XX XX X

4:00 XX XX XX XX

and so on, repeating every 4 hours.

The inventor of the patent is Richard Kramer, and the patent was assigned to General Time Corporation (parent company of Seth Thomas at that time).

The fact that General Time, and not Hermle, received the patent, leads me to believe that this movement was specially made for Seth Thomas. Later, of course, other companies used this movement in their clocks (including the Chelsea “shipstrike” clocks).

One interesting feature of Kramer’s design is that a “dummy” strike without the bell is performed at 15 minutes before the hour. This prepares the strike for the next hour, when 1, 2, 3, or 4 pairs of strikes are sounded. In later years, the design was changed, and the “dummy” strike cycle was eliminated.

Related posts:

1. 1866 Patent for American Style Loop End Clock Mainsprings
2. Mainsprings for Seth Thomas No. 89 Movements
3. A Tale of Three Movements and a Clock (Ansonia Long Drop Regulator A)