400 Day Anniversary Clock Repair: Schatz, Kundo, Kern and Others

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!

Schatz standard 400 day clock dated 10 54 (October 1954)Kern Diamond Dial 400 Day ClockSchatz standard 400 day clock, dated 11 52 (November 1952) on the movement. Has engraved, silvered dial.Schatz London Coach 400 Day Clock

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.

Prices To Repair Wind-Up 400 Day Anniversary Clocks

$325 - $400 typical price to overhaul the movement and replace the suspension spring.

Two year warranty. The suspension spring is the thin flat wire that the pendulum hangs on. (I give a price range to allow for parts or extensive repairs that may be needed. If the clock is in very bad condition and the price will be higher, I will notify you before starting the repair.) The price will be at the low end if the movement is in excellent condition and the pivots don't need polishing. The price will be at the high end if many pivots need polishing and the mainspring needs replacing. Add $18 if the lower suspension block is missing (the rectangular brass piece with a pin through it that the pendulum hooks on to). The clock will have a two-year warranty when finished.

Suspension Guards:

Most 400 day clocks from the 1950s on have a "suspension guard", typically a brass tube or cover, to protect the suspension spring. If the guard is missing, I will replace it, so that your clock may be returned to you without damaging the suspension spring. A typical guard costs $45.

$41 return shipping & insurance (continental US).

$165 to polish and lacquer a plain polished round base and the pillars.

(Polishing is available only as part of an overhaul - it is not available as a separate service.) (Note: don't polish the clock yourself unless you are prepared to disassemble the parts before polishing. If left assembled, polish will remain in the joints and crevices, possibly causing corrosion. At this time I am polishing plain round bases only.

$125 to replace and adjust suspension spring only (plus $41 return shipping).

The suspension spring is the thin flat wire that the pendulum hangs on. Add $18 if the lower suspension block is missing (the rectangular brass piece with a pin through it that the pendulum hooks on to). There is no warranty if the suspension spring is replaced without the clock being overhauled.

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 $95 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.

Schatz diamond dial 400 day clock dated 10 52Schatz square dial 400 day clock dated 2 53 (February 1953)Kern standard 400 day clock from the late 1950s or early 1960sSchatz standard 400 day clock with cream color painted dial background. Dated 9-52 (September 1952)Kundo standard 400 day clock from the 1950sSchatz 400 day clock dated 2-54 (February 1954). Has the special glass dome with the hole in the top. Schatz miniature 400 day clock dated 5 56 (May 1956) on the movement.1950s Heco miniature 400 day anniversary clock made by Kern & Sohne in Germany.

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.

Note on base polishing:

Sometimes a 400 day clock base will develop "stress cracks" caused by the working of the metal when the base was manufactured. If there are only several short vertical cracks, the base may be able to be polished successfully. Early Kundo bases with cracks running around the base may come apart if polished.

How to Pack and Ship Your 400 Day Clock for Repair

You may send your Schatz or Kundo 400 day clock now for repair, and it will finished in about 4 - 5 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.

Our Address is:

Bill's Clockworks
8 W. Columbia Street
Flora, IN 46929

E-mail: [email protected]
Phone: (574) 967-4709
Toll-free Phone: 1-888-742-5625


I will not need your key - please check the key and make sure it fits snugly. If it fits loosely, it should be replaced. Please enclose a note saying if you need a new key. The key will be $10 to $15, depending on the model of clock.

Dome: I will not need the clocks's dome or cover.


If there is a locking device, lock the pendulum into the clock. For a Kundo clock (if it has a lock), raise the pendulum into the opening, then secure the locking arm with several paper clips through the hole to hold it firmly in the locked position, and tape it as well. For other clocks, tape the locking arm in the locked position (tape on the underside of the base to avoid damaging the finish). Put paper towel below and around the pendulum to help support it. If the pendulum does not lock, wrap it in bubble wrap and put it in the bottom of the box.


Wrap paper towel or tissue paper around the base to protect the finish. Wrap the entire clock in four to six layers of bubble wrap.


Use packing peanuts for padding around the wrapped clock. There must be at least 2 inches of packing peanuts between the wrapped clock and the box on all sides. The flexible peanuts are better than the rigid type, as they don't break down into crumbs. Pack firmly so the clock won't move around. Don't use Styrofoam sheets, as it does not provide good padding and may disintegrate. There must be enough packing peanuts to hold the clock in position so it won't move around in the box.

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.


No payment is due until the clock is repaired. You may pay by check, online, or call in a credit card number.

(Haller Clocks:

Please do not send a clock made by Haller for repair without checking with me first. Some of them use many plastic parts and I don't recommend repairing them.)

How to Unpack and Start the Clock

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.

Why 400 Day Clocks Run So Long

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.

Standard 400 Day Clock (about 12 inches tall)

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 Clock (about 8 - 9 inches tall)

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):

How To Tell When A Schatz Four Hundred Day Clock Was Made

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.

How I Repair Your 400 Day Clock