Late Jahresuhrenfabrik (JUF) 400 Day Clock

I recently repaired this 400 day clock. The maker, Jahresuhrenfabrik (German for Year Clock Factory, often abbreviated JUF by collectors), later became known as Aug. Schatz & Sohne. These later clocks often say “Schatz” on the dial, and have a date code stamped on the back starting around 1952.

This clock here has 6 47 stamped inside the front plate, and I wonder if this means June 1947? The suspension guard is different than the later, standard ones. It has a threaded stud on the back with a nut that screws on, as opposed to a thumbscrew. This is the first time I’ve seen this type of suspension guard. I understand that suspension guards became popular on 400 day clocks in the late 1940s or early 1950s, but I haven’t seen any documentation about this.

This clock’s top decoration (arch) is different than usual.

See more pictures.

Repair job 8793. My procedure is to disassemble the movement (including taking the mainspring out of the barrel) and clean the parts. Then I do the needed repair work, in this case polishing the pivots, replacing the damaged mainspring barrel and use an oiled smoothing broach to clean out and polish the pivot holes (400 day clocks don’t usually need bushings). Also, make sure the anchor pin is screwed in tightly, and polish it if needed. Any parts I touched are cleaned again, and the movement assembled and lubricated. Then I installed a new suspension spring, 0.004″ thick.

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  1. 400 day clocks before the 1950s had steel or bronze suspension springs. The Horolovar springs are an alloy which is stronger. Still, they do get broken once in a while, but only when the user is careless.

  2. Bill do they make the new suspension wires stronger now? It seems most 400 day clocks have broken suspension wires.

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