Koma Miniature 400 Day Clock

I just repaired this Koma (Konrad Mauch) miniature 400 day clock from the mid-1950s. The case is 8 1/2 inches tall (not including handle), and is 10 1/4 inches tall including handle. The dial’s diameter is 4 3/8 inches overall. The case has glass in the front and sides, and a hinged brass back door. There is a knob on the back of the movement which is pulled out and turned to set the time.

The movement is similar to Horolovar back plate Nos. 1395C, 1398, 1398A, 1399 and 1399A but says “W4” in the upper left corner.  The Horolovar 400 Day Clock Repair Guide says that these movements need suspension unit 14A with a .0032 inch thick suspension spring. When I tried the .0032 inch spring, the clock ran too fast. A .0031 inch spring makes this clock regulate properly, with the pendulum’s regulator near the center of its range.

Below is a video of this clock:

Here is a slideshow of this clock:

Repair job 5025.

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  1. just working on exact same clock… w4 not listed in horovlar.. bought with broken mainspring in awful state. put in replacement, very troublesome, reassembled, then spring barrel cap popped off, so having to start again.. at least it ran after a fashion for a few beats on one wind of the spring, befoore i tried full spring torque.. barrel quite damaged, outer anchor has pulled out…. its one of five torsion clocks am resuscitating now… .0031 susp spring info useful… thanks for your posting..

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