Two years ago, I wrote about the P-1956 mainspring from Merritt’s Antiques. This spring was ideal for many antique American clocks.
My newest batch of these mainsprings (received late in 2009) are weaker than the first batch I had. When removed from their clamp, they open out to only 5 1/2 inches (my first batch opened to about 11 inches).
These springs may be too weak for clocks with a recoil escapement. I still need to test them in a Seth Thomas No. 89 movement.
Here is another “Plymouth” tambour mantel clock by Seth Thomas (see this post for two others). This one does not have a date code, I estimate that it is from the early 1930s. It has a no. 89I movement that strikes the hours and half-hours on a coil gong. The movement has a code of R-6 on the back.
The case is 19 3/4 inches wide and 9 1/4 inches tall. The dial has a 4.5 inch time track, and is aluminum with embossed and painted numerals.
The movement has the original mainsprings that still open up very far and provide plenty of power. They are 3/4 inch wide loop end springs. The thicknesses are:
Time mainspring: 0.017 inch
Strike mainspring: 0.0167 inch
Aluminum dial with embossed numerals
The case is 19 3/4 inches wide and 9 1/4 inches tall
Instruction label inside the back door
Seth Thomas movement no. 89I. Has code R-6
Job 5146. I had last repaired this clock over 10 years ago, and it just needed to be disassembled and cleaned to make it run well again.
The Seth Thomas “Office No. 6″ is a wall clock in a rectangular wooden case. Time-only and time and strike versions were available. The earlier ones had a removable scroll top and a bracket base, but by 1924 it was being made in a plain case.
This example looks similar to that in the photo labeled “1924″ in Tran Duy Ly’s Seth Thomas clock book. The case is dark mahogany, 31 inches tall, 15 5/8 inches wide, and the dial has a 10 3/4 inch time track. The movement is 8-day time only, no. 123 E. I first overhauled this clock in 1999 (polished pivots and installed 5 bushings). It ran until 2009, when the click broke (an uncommon occurrence).
I cleaned the movement and did the following repairs:
Installed a new click;
Installed a new mainspring, as the old one had a squeaky action even after cleaning and oiling. I installed a Merritt’s P-1956 3/4 x 0.0165 x 96 inch mainspring (the new spring opened up to 5 1/4 inch diameter after being wound and unwound 5 times).
The pivots, which I had polished during the last overhaul, were still in excellent condition.
This movement has stopworks for the mainspring, I set it up so that it stops the winding when the spring is one turn from being fully wound. The case has a beat plate, and the motion of the pendulum measured on the plate is as follows:
Escape arc: + and – 0.75 degrees
Wound up: + and – 3.3 degrees
Rundown 3 days: + and – 3.2 degrees
Rundown 7 days: + and – 2.8 degrees
The paint on the dial was flaking badly, and the customer wanted it restored. I had it repainted by The Dial House in Dallas, Georgia.
Here is a slide show of the clock and its movement:
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:
“Adamantine” was Seth Thomas’ trademarked name for a celluloid finish over wood. Besides the mahogany color shown here, it was made in black, white, green, brown, tan and other colors. These cases are durable, and can usually be polished to look very nice. Sometimes the colors fade with age. Adamantine clocks were made from about the 1880s to the 1920s.
This beautiful mahogany Adamantine clock came into my shop recently with a broken time mainspring. Nothing too exciting about that, but I think this clock is so nice looking that I decided to show it here. I had previously repaired it 11 years ago, overhauling the movement and polishing the case and bezel.
I replaced the broken time mainspring with a Merritt’s P-1956 3/4 by .0165 by 96 inches (the original spring was 0.0172 inch thick). The pendulum takes a superb motion (almost too good) and so an even thinner mainspring would work. During my previous overhaul, I replaced the way too strong strike mainspring (an incorrect replacement) with a spring about 0.016 inch thick.
I repaired this Gilbert “Parole” shelf or parlor clock that was made about 1880. The walnut case is 19 1/4 inches tall. I polished the pivots and installed bushings (a previous repairer had punched the pivot holes to try to close them).
The clock had its original mainsprings, both of which were marked “W. Barnes Patented Nov. 27, 1866″. The strike spring was quite thick (0.02 inch). Both springs were stiff and very hard to remove from the mainwheels. I installed new Merritt’s P-1956 mainsprings that are 3/4 by .0165 by 96 inches. They provide a good escapement action and striking speed. Gilbert clocks of this type take a large pendulum swing with a small amount of supplementary arc (overswing) due to the design of the recoil escapement. I slanted the back of the mainspring arbor hooks to make the mainsprings easier to remove for future cleaning.
I repaired this New Haven long drop octagon clock. Some of the pinions had worn wires, so I replaced the wires in one pinion and reversed the wires in three. I polished the pivots and installed 13 bushings.
The mainsprings appear to be original (they match in color and style and look old).
Time mainspring: 3/4 inch wide by 0.0172 inch thick. This spring provides sufficient power, as the escapement motion is excellent.
Strike mainspring: 3/4 inch wide by 0.0142 inches thick. This spring is very thin, yet the striking speed is fine.
I retained both original mainsprings in this clock. They were in good condition, operated smoothly, and provided enough operating power, so there was no reason to change them. A good old mainspring is no more likely to break than a new one. (Some repair shops install new mainsprings in every clock they repair, I disagree with this practice.)
The case is 33 inches tall, and the minute track diameter is 11 inches.
I recently overhauled this Sessions black mantel clock from around 1903 – 1910. It was a routine overhaul including polishing the pivots and installing bushings. A previous repairer had installed two screw-in bushings (a no-no!). I replaced these with KWM size 4 American bushings. The mainwheels were made with Gilbert-style clicks, which are more robust then the standard Sessions clicks.
The original mainsprings seemed too strong. The time spring was 0.0182 inch thick, and the strike spring was 0.0178 inch thick. I replaced both with thinner mainsprings, Merritt’s Antiques P-1956, 0.0165 inch thick, to reduce future wear to the mainwheel teeth. The escapement takes an excellent motion.
