Key wind 400 day (anniversary) clocks were made from the 1880s through the 1980s. They were especially popular in the 1950s, and the major German makers were Schatz (Aug. Schatz & Sohne or Jahresuhrenfabrik), Kundo (Kieninger & Obergfell) and Kern.
I've been repairing 400 day clocks for over 40 years and they are one of my favorite types of clock. They run silently, needing to be set every one to two weeks, and wound whenever they run down (typically every 9 - 13 months). Since they are mechanical, don't expect them to be as accurate as modern quartz clocks!
Bill's Clockworks is located in Flora, Indiana (about an hour north of Indianapolis). If you are too far away to visit us, we'll be happy for you to send your 400 day clock to us for repair. Packing and shipping instructions are given below.
We take the time to repair your clock properly. The movement of your clock is disassembled, cleaned and examined. We polish any rough pivots, replace the mainspring if necessary, repair or replace any damaged parts, and do a final cleaning. Then the movement is assembled, lubricated, adjusted and tested. We guarantee our work for two years.
After receiving your clock, I will examine it and let you know if the repair cost will exceed the estimate given above. If you decide to have the clock returned without repair, the charge will be $60 for the estimate and return shipping.
Below are photos of some of the 400 day clocks I have repaired. See my blog for more details.
Note: If your clock has been repaired by someone else and still doesn't work, I will be happy to repair it, but the repair bill may be significantly higher than stated above. I recently received a clock that had unsightly blobs of solder and bent wheel teeth, requiring replacement of two major parts.
You may send your Schatz or Kundo 400 day clock now for repair, and it will finished in about 6 months. Please contact us if you need expedited repair service.
Please contact us about any 400 day clock other than Schatz or Kundo before sending it.
8 W. Columbia Street
Flora, IN 46929
E-mail: [email protected]
Phone: (574) 967-4709
Toll-free Phone: 1-888-742-5625
IMPORTANT NOTE ON PACKING! If your clock has three finials (pointed decorations) above the dial: These finials are fragile. They MUST NOT touch the box during shipping or they may break off. Be sure that there is enough bubble wrap over the finials. Then be sure that 2 inches of packing peanuts are between the bubble wrap and the box. On Schatz standard size 400 day clocks, please unscrew the finials (if they are not on too tight) and keep them to reduce the chance of damage in shipping.
Please include a note with your 400 day clock with your name, address, e-mail address and phone number. Please state if you would like the base polished. I'll e-mail, call or write you to acknowledge the receipt of your clock when it arrives. If the repair will cost more than the above prices, I'll notify you.
Be very careful when unpacking the clock and removing the bubble wrap. When I return your repaired clock, I will include specific instructions to unpack and set up your clock.
After following the instructions for unlocking or attaching the pendulum, and leveling the clock, start the pendulum as follows:
Rotate the pendulum gently one-half (1/2) turn only and release it. The clock will then start running.
The suspension spring (thin flat wire) that that the pendulum hangs from IS VERY DELICATE and must not be bent or twisted in any way. Damage of the suspension wire by the customer is NOT COVERED BY THE WARRANTY.
Typical clocks run either one day or eight days on one winding. To make 400 day clocks run longer, a torsion pendulum is used. A torsion pendulum hangs from a thin flat wire and rotates in one direction and then the other, instead of swinging back and forth as a standard pendulum does.
A Standard or full sized 400 day clock has a torsion pendulum which makes a rotation in 7.5 seconds, or 8 rotations each minute (four rotations in each direction). The clock makes one “tick” near the end of each rotation. Preceding each tick, a gear with pointed teeth called the escape wheel has been giving an impulse to the pallet assembly. During impulse, a vertical pin in the pallet assembly pushes a fork to the left or right. The fork applies this energy to the suspension spring (the thin wire holding the pendulum), and the suspension spring transfers some of this energy to the pendulum.
The clock movement supplies one unit of energy to the pendulum for each oscillation. A torsion pendulum oscillates about 8 to 20 times more slowly than a swinging pendulum. This represents a major savings in energy, enough for an 8-day clock run 64 to 160 days. Further energy savings is obtained by using smaller pivots (load bearing areas on the ends of gear arbors or shafts) and by using small gears. By having more gears than an 8 day clock, the mainspring is made to unwind slowly enough for the clock to run about 400 days.
Miniature 400 day clocks are built on the same principles as the standard models, but use smaller gears and pivots, making them even more energy efficient. The most popular models, those by Schatz and Kundo, have pendulums making 10 rotations per minute. Other makes have pendulum rotation rates of from 6 to 10 rotations per minute.
Below are some movies showing 400 day clocks in operation (note - 400 day clocks do not strike or chime, the sounds you hear are in the background):
Many Schatz clocks from the 1950s, 1960s, and early 1970s have a date stamped on the back of the movement. There will be digits for the month and the year. For example, 12 57 means December 1957.
Schatz also made clocks which would run for 1000 days on one winding (see Why 1000 Day Clocks Run So Long).
See my blog for examples of 400 day clocks I have repaired.