Krafts Clock Repair

The Anniversary Clock

The original anniversary clock is a mechanical spring driven clock with a spinning pendulum. The clocks are very ornamental, have an "old world" style and are usually made of polished lacquered brass and crystal. Given as wedding gifts they are, for many years, proudly displayed on  the mantel.

History

The actual history of these clocks is very complex, with many different manufacturers being involved in making them and many different stores selling them world wide. It is beyond the scope of this short article to give the complete history here but a short version can be given.  The term "anniversary clock" was copyrighted by Bowler & Burdock Company in 1901, an Ohio clock-making firm. However, these clocks were manufactured before this date, going as far back as the early 1800's. The"400 Day Clock"  became a popular term. The 400 Day Clock, with its special torsion pendulum, was first invented by an American named Aaron Crane who patented it in 1841.

However,  for one reason or another, the clocks were manufactured in Germany.

Significance

Identification

You can see the inner working of these clocks as they are covered in a glass or crystal dome. Typically made of brass, the rotating pendulum has three or usually four brass balls that spin back and forth slowly over the clocks base. Many times, the store selling these can engrave the wedding date of the happy couple on it to commemorate their wedding day.

How it Works

Originally the mechanical anniversary clock was a torsion clock meaning that its pendulum hangs on a thin flat spring called a suspension spring. It had a mainspring that needed to be wound once a year, or really 400 days. Now a days, they are quartz battery powered clocks, and the pendulums are driven by a motor mounted on the base's bottom and the movement is also battery driven. Some clocks chime while others only tell the time. The pendulum on all of these clocks rotates clockwise and counter-clockwise, instead of swinging back and forth.  As the spring twists it triggers or releases the escapement of the clock which makes it keep time. The mainspring supplies all the power to keep it running.

Considerations

Genuine mechanical anniversary clocks are rather delicate, difficult to set up and don't keep very good time. All mechanical clocks have an error where they either gain or lose a certain amount of time in a week. For instance if the clock loses 2 minutes a week, at the end of a month it will be 8 minutes slow. So 400 day clocks need to be reset once in a while to make them keep time. Quartz clocks do not suffer from this however. Mechanical clocks are effected by temperature changes, which play havoc with its delicate suspension spring, which is also easily broken or damaged.

Timing

It takes patience to time a mechanical anniversary clock. To start out, make sure it is wound fully, and placed on a level flat surface where it will not be disturbed by vibration. Do not move it to dust, but dust around it, they are very sensitive and easily damaged.

After a week of running, see whether it is fast or slow. Remove the dome, and look at the top of the pendulum. You will see a brass disk that has Fast, Slow, and arrows on it. Some even have graduations inscribed on them. This is what you will move to time your clock. While GENTLY holding the pendulum, If it is fast, turn it about a 1/16 of an inch distance towards slow in the direction of the arrow, then restart the clock and let it run another week. This will take several adjustments, and when you come close you will need to move it less. For instance when you have it running very close to being on time, you may only need to move it a distance of 1/64 of an inch to change its time keeping. But after this point you are better off leaving it at that setting.

These clocks are very interesting to watch while they are running, and are also beautiful time pieces.