Edifying

- November 26, 2023

Your local horologist had never replaced a movement before. Well there's always a first time!

In our last episode we reviewed options for Ed's Seth Thomas Tambour clock. Replacement seemed the best choice but research was needed.

There are few makers of mechanical movements still cranking out new versions. Hermle movements are most commonly found in clocks manufactured in the last 50-60 years and their movements are most commonly used for replacements.

Your movement researcher came to understand that there are very few new movements made with balance wheels (like the one in Ed's clock) and the options for selecting one of those was quite limited.

Furthermore, as much as the design of the Tambour is attractive, it is also a bit cramped in the case so...

Etc., etc., etc...

Turns out the basic dimensions of the movement is of a standard size still in use today. Excellent.

And there is a balance wheel version that is made today. Excellent.

Your local horologist also knows that there is a fine fellow named Mark Butterworth who is a regular on the NAWCC boards and runs a supply shop for clockmakers, Butterworthclocks.com, and is a top reseller of Hermle movements.

But one does need to be in the trade to order from them.

So your intrepid tradesman made a call and...

Wait there's an important additional item!

This research robot did a bunch of extra measurements and analysis. There is a pendulum version of that movement that would fit in the case.

Knowing Ed reasonably well and having an opinion about replacing the movement, your horologist called.

"Ed, how about we put in a pendulum movement instead of a balance wheel? It's easier to service and..."

"Great, I prefer pendulums anyway."

So...

Mr. Butterworth was a nice as can be and set me up with an account (enabling a nice discount from the commercial price of the replacement movement).

Fast forward a week and the movement arrived. Nicely packed and definitely German.

Installing the movement was pretty straightforward.

But... there was one other issue that Captain Obvious noted and had some thoughts about how to address.

Here is a shot of Ed's old movement.

And the new one.

The hammers are reversed.

Not immediately obvious as they superficially look aligned in the two photos but the top photo is showing the front plate side of the old movement and the bottom photo the back plate side of the new one. When the movement is inserted it is the back plate that will face the rear door of the clock. The hammers are reversed.

When you open the door to Ed's clock you will see the rods are fixed to a metal base which is screwed down in the case on the right.

With the old movement the hammers would align to the rods like this.

But with the new movement in the case the rods sit in the opposite direction. The hammers need to strike the rods near their base to make a proper tone.

Many options were considered. No, the thing just had to be reversed.

The rod base needs to be flipped to the other side and the rods pointing oppositely.

Another call with Ed. He approved the surgery.

The rods came out easily.

Because we were flipping the base to the other side and pointing it in the opposite direction the rods themselves had to be reversed.

Why? Because this clock is a Bim Bam. For each hour two rods are struck then one. "Ding dong."

If the rod base was flipped but the rods kept in their same positions the clock would strike "dong ding."

I tried it. It sounded bad.

Easy enough to swap rod A with rod C and call it a night.

But the rod base relocation would require some minor surgery.

That rod base couldn't just be flipped. It had to be reseated with new anchor holes. Just over 1.5 inches to the left of the original holes according to this geometrist.