Escapee

Behold an animated gif made by your local tech geek horologist of the escapement in Charlene's Ingraham Regulator.

And, as discussed in our last episode, something was amiss with the ticking of this clock.

When visiting Charlene at her home YLH noticed that the clock, as it ticked, was making a few extra noises.

Instead of the simple tick-tock, it sounded like it was clanging, with lots of extra clicks in each swing of the pendulum.

Regular readers [crickets] will know that this horology student is... no longer a freshman. 

Somewhere between a sophomore and a junior clockmaker would not be an unfair assessment. Knowing where all the classrooms are, which bathrooms are trouble, the hallways that ok to traverse and those to avoid... 

Ahem.

That ticking didn't sound right to this clock doc.

Take a listen / look at the video below. Turn up the volume and loop the video if you can (right click on it and hopefully there's a loop option).

What you will hear / see is the sound and motion of the swing of the crutch and top of the pendulum but really it's about the sound. Watch the assembly do the following and listen to the sounds in each direction:

1. a normal (single tick) swing from left to right 

2. a noisy (multiple clicks) from right to left 

3. another normal (single tick) swing from left to right

What was not obvious, even closely examining the movement, was from where these sounds emanated.

Yet this no-longer-a-freshman horologist had some ideas about where to look.

First, the pendulum bob.

As noted in our earlier episode, Charlene acknowledged that the pendulum was a replacement and YLH knows that some of these more modern versions can rattle a bit.

Here's Charlene's pendulum resting in the clock case, disconnected from the movement for safer transport.

The function of a pendulum is to regulate the speed of the movement and that speed can be adjusted in some clocks by raising or lowering the bob (the round disk).

Pendulums with wooden shafts typically will have a threaded metal rod attached to its end held in place with a rating nut. The shaft is inserted in slots or sometimes, especially with more modern pendulums, through the bob.

Like this:

The bob rests on the rating nut which when turned will gently raise or lower the bob.

In the case of this pendulum (and again it is a common modern design), the shaft is gently pressed / held in place by that wedge of metal with the curved top edge.

The shaft has some wiggle room and if the edge of that metal wedge isn't snug...

In fact there was a metallic and hollow quality to some of those noises YLH noted.

The pendulum bob is made of metal and it is hollow...

Yep. That wedge was rather loose in its required pressing against the shaft of the pendulum. It created a rattling noise just by a gentle shake of the pendulum.

A bit of pressing on the wedge and the shaft was now much more snug up against the bob.

Progress.

OK how about the noise? Time to put the movement back up on the test stand.

Yep those rattling sounds were now gone.

Excellent.

Right?

But...

But...

Sigh. 

YLH heard it.

There was still what sounded like an extra ticking sound in the beat of the movement. 

Consistent. 

Not tick... tock.

More like tick... ticktock... tick... ticktock.

How to troubleshoot this?

Well there is one modern tool in this horological arsenal that has proven itself useful many times over.

The video capability of iPhones is remarkable. 

Especially the Slo-Mo feature.

Again turn up the volume and have a look/listen. 

That double tick sound right at the end of the swing to the right was consistent with every swing of the pendulum.

Hmm...

The pendulum shaft and bob were snug. 

Hmmm...

We made the ticking less noisy but there was still something else happening that needed attention.

Hmmmmm...

This clock detective suspected that this remaining sound was coming from the escapement itself.

Hmm...

Next time...