Grandfather Clock Moon-Dial Installation

Grandfather Clock Moon Dial Installation

A Grandfather clock moon-dial installation explanation is in this section. Thus, this is written for a new movement installation in mind.

However can use it for any post WW2 German mechanical unit with issues in relation to the front of the movement.

The Moon Gear

Install the moon gear onto the new movement prior to the clock moon-dial installation. It mounts with a set screw and sits on the same tube as the hour hand.

Install this onto the new unit. Of course it has to be the same as it was on the old movement. Ideally, with the same approximate distance on the hand shaft. In essence, this will allow it to run the gears behind the clock moon-dial and therefore run the phase of the moon.

The Selector Switch

A selector switch is a steel arm that is about 1 to 2 inches in length with a set screw. In short, the purpose of the switch is to select the song or silence the clock. Install the selector switch on the arm which is on the right side of the movement.

In other words, slide the switch over the larger arm and secure it with the set screw. It only has to be able to come through the slot at the 3 o'clock position for the user to move it up or down on the clock moon-dial.

Before Install, Check This

These modern clock movements from Germany use a rack and snail count system for the strike. Be sure the rack tail for the strike is on top of the snail instead of stuck behind it. See pictures that illustrate the correct and incorrect positions.

Simply lift the rack back up into position with fingers. If this is not done the clock may not run, chime, or strike. It is important to get this done before completing the grandfather clock moon-dial installation.

Grandfather Clock Moon Dial Installation

The clock moon-dial has four posts on the back that lock into the front plate of the movement. Line up the clock hand shaft to the hole in the center of the dial. Then line up the posts with the holes in the movement.

There are two ways to secure the four dial posts to the clock movement. One way has locking arms on the back of the front plate of the movement that slide over the end of the dial post to lock it tight. This is if both the clock moon-dial and the movement are made this way.

The other way this is done is if there are holes in the ends of the dial post feet. These use a pin to secure it to the movement. A tapered pin will go through the hole in the post after it's on the front plate of the movement.

Moon Gear

Moon Gear Mesh

Rack Incorrect

Rack is Correct

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Updated on: 01/01/2025