Three matching Jahresuhrenfabrik (JUF) 400 day clocks ca. 1910 were in my shop at the same time. They have a smaller disc pendulum and thinner suspension spring than many JUF 400 day clocks, and date from around 1910.
Many JUF disc pendulum clocks use a 0.004 inch thick suspension spring, but these 3 clocks have a 0.0035 inch thick spring.
The disc pendulums are smaller in diameter than usual, but taller. They are about 2 3/4 inches in diameter, as compared to the more usual 3 1/4 to 3 3/8 inches. The pendulums have an iron core with a brass sheet spun around it, painted gold on the bottom.
Data:
Clock 1 (my number S-0634): Pendulum diameter 69.5 mm, pendulum weight 11.2 ounces.
Clock 2 (#2 in my collection): Pendulum diameter 69.5 mm, pendulum weight 10.4 ounces. I bought this clock in 1988, and restored it at that time. It still runs well and looks good!
Clock 3 (belonging to my father-in-law): Pendulum diameter 69.5 mm, pendulum weight 11.2 ounces.
All three clocks are Horolovar back plate number 1260 (having Jahresuhrenfabrik Germany G.m.b.H. in a circle around the second wheel pivot, and 2 standing elephants facing each other with a bell-top leg model alarm clock in between).
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Update:
I fitted a 0.0035 Horolovar suspension spring, with an overall length to put the bottom of the pendulum within 1/4″ of the clock base, and so far it’s running well and within built-in regulation/adjustment range.
Passmore (and my early Terwilliger) seem to have missed this size/weight of pendulum.
I’ve just obtained a JUF with matching backplate and pendulum numbers (125336). No circles or elephants.
Using Passmore as a guide I fitted a 0.004″ suspension wire and it goes way too fast to adjust to timekeeping.
The pendulum is 71.5mm diameter, and weighs 306g (10.79oz). I thought it was missing 60g as Passmore states weight is 370/380g…..
Searching for clues, I came across this article, which has given me hope that all I need try is a 0.0035 spring, so thanks !
I have a Jahresuhren-Fabrik G.m.b.H. I haven’t found one online that quite matches mine. Some major differences that I see are as follows :
• the face just says Germany – not made in Germany
• the pendulum weighs 12.70 oz
• the double elephants are not directly under the name- they are almost centered on the very bottom of the backplate, while the JUF name is off center and to the right
• the inside front plate has an 8 to the left and a 47 centered. Can you shed any light on this clocks age?