My Chauncey Jerome 30-hour Ogee weight driven time and strike clock has stopped for no obvious reason. Let’s see if we can get it going again.
But first, no-one can deny that Chauncey Jerome had made a historic contribution to the American clock industry in the 18th century when he substituted brass works for wooden works and was said to be “the greatest and most far-reaching contributor to the clock industry.” Although he made a fortune selling his clocks, and his business grew quickly his company ultimately failed in 1856.
After researching Mike Baileys excellent site on Jerome clocks I was able to determine that my clock is a number 11 Ogee made just before the Jerome bankruptcy, 1855. The patent 30-hour brass movement is the number 1.314 which is likely in its original case.
The only time I serviced the movement was in February 2018. It was dirty as expected and it appeared that no work had been done for quite some time. It was well worn. At that time 8 bushings were installed, 4 in the front and 4 on the backplate. Most of the wear was on the strike side and lower in the trains.
It ran very well for 3 years and now (May 2021) it has stopped.
I performed the usual checks prior to taking the movement out of its case. I inspected the time-side cable for kinks and that it was not binding. A binding cable will definitely stop a clock. It was fine.
I checked the crutch loop clearance and found nothing seriously amiss. It should have run. It did not.
While it was running I noticed that it was drifting in an out of beat and it ran no longer than a minute or so before stopping. This indicates a number of issues; a bent escape wheel teeth, damage/wear to its lantern pinion, a bent escape wheel arbour or an enlarged pivot hole. I suspect the last one is the culprit.
The strike side is fine and it is functioning as it should, but without the time side running correctly the clock is just an ornament.
Next, taking it out of the case
I checked it over and determined that the movement required two new bushings, one for the escape wheel bridge and the other for the hour wheel in the motion works. I did not have a multi-level bridge tool when I serviced this clock the first time three years ago so, it came in very handy. The hour wheel pivot hole looked fine then but now there is enough wear that it justifies being done. I checked the escape wheel arbour and it was straight.
With those two wear issues addressed I put the movement back together for testing and assumed that the clock would run. Unfortunately the clock stopped after less than a minute. Something else was amiss.
The trouble with trundles
I adjusted the beat but still nothing. I noted where the second wheel, time side, was stopping as it would stop about every eighth of a turn. Since the second wheel gear teeth are in excellent condition, it could only be one thing, worn trundles in the escape wheel lantern pinion that prevent the second wheel from meshing correctly with escape wheel.
As you can see in the above photo the trundles are in terrible condition and there is little doubt that this is what stopped the clock. Wear such as this cannot be ignored. Without a repair the clock will not run.
Trundles are often replaced by drilling out the shroud end where the trundles are inserted, taking the worn trundles out, replacing them with new ones made from pivot wire and staking the holes to ensure they stay in place. On this escape wheel the cap must be removed to access the trundles. This is common on ogee movements such as this and it means a different approach for the repair.
I secured my crow’s foot to my bench vice, inserted the top cap of the lantern pinion into the V part of the foot and gently tapped on the pivot end to release the cap. It released easily. The trundles should have literally fallen out but two of the 6 were firmly in place and had to be cut and drilled out. Not fun.
I have a good assortment of pivot wire, selected a .95mm wire for the trundles and cut each one to length with a Dremel cutting disk.
I used a hollow staking tool to push the cap back in place and the trundles into their respective holes but the cap was loose. This is when Loctite is your best friend. Using a toothpick I dabbed a small amount onto each end of the trundles, secured the trundles in place and waited 24 hours for the Loctite to cure.
The next day for testing purposes I left out the strike side levers and wheels.
On the test stand the movement ran a couple of 30-hour cycles and the issue has now been addressed. The remaining gears and levers were assembled into the movement and the movement was placed into the case for a final test of both the time and strike side.
It should run reliably for years to come.
From time to time a repairer will have to deal with worn trundles.
If a clock stops and there is a gear meshing issue, then it is time to replace the trundles but if they are a little worn and the clock runs well, I tend to leave them as-is knowing that at some future date if the clock stops it is one of many issues I will address.
I have mentioned this before but if you are just beginning your journey into clock repair, the 30-hour ogee, because of the large gears, the overall simplicity and the absence of mainsprings make this a great place to start.