Digging it / in

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In our last episode your local horologist told the tale of reconnecting with Jeff (the master clockmaker) and the daunting offer to collaborate on some clock work.

And so we landed on the Thomas Adams English bell strike movement.


Yes that seatboard is way off kilter. Something to explore when / if this horological hack ever gets to the "install it back in the case" stage with this beastie.

Jeff provided a verbal description of the clock case and the various issues he unearthed in working on the movement as well as his original notes captured when he first evaluated the clock.


Your correspondent will skip some of the smaller details and stay on the big stuff.

Summarily Jeff notes: 

An "Astro Regulator" Time & Strike.

Astro? 

The back cock is cracked. This particular "cock" is the piece that supports (from which hangs) the entire pendulum (and reminder... that weighs a ton).

The "fly" is broken. The fly is the last arbor on the strike train that has a fan blade instead of a wheel. It's function is to slow the speed of the strike train.

The hour wheel has a problem engaging with the wheel above it.

It needs new weight cords.

The pendulum has been repaired extensively (and is still a bit of a mess).

The pulleys (for the weight cords) need repair.

There's a missing ratchet (click) on the main wheel Time side.

Whew!

Now then.

At the time of this hand off Jeff had already addressed the broken fly and perhaps the most concerning issue: the cracked cock (AKA the suspension bridge).

A good example of an English clock suspension bridge / cock can be found on the Peter Green clock. 

The crack on this cock / bridge was massive. Your horological photo snapper is showing the cock post disassembly.


YLH wonders if it didn't fail catastrophically and whether that might account for the dents in the remarkably heavy pendulum it has to suspend. Jeff riveted an L shaped brass support on each side of the cock. That should keep it aloft.


We'll come back to this.

As for the broken fan, Jeff reported that one blade had nearly snapped off. He soldered the ends and added a metal band for tension against the arbor (helps with speed control).


We'll come back to this as well.

A few other bits were covered by Jeff but those two fixes are the major repairs he completed.

What follows all took place in YLH's shop.

An inspection of the assembled movement ensued.

As noted in our last episode, the strike train was locked up, and this was not mentioned in Jeff's summary. 

Your clock detective discovered the source of the problem: The hammer spring was jammed against a wheel. The hammer spring pushes the hammer arm causing the hammer to strike the bell.

Here's a view of the movement. There's the hammer and it's arm.


Here's a close up from another angle revealing the problem.

The spring is a flat strip of steel with a sharply angled head, almost like an upside down foot. That head is jammed against the third wheel of the strike train.

Note the super enlarged close up of the collision on the right.


That will be an interesting challenge.

Jeff's notes called out the hour wheel engaging problem. That wheel was part of the additional set of wheels that dropped below the movement into the cutout of the seatboard.


Oh and that soldering job on the rack tail. Yikes.

Here was the engagement problem: The hour wheel teeth were not meshing with the pinion above it. Everything was too... wobbly.


One last bit before we take this bad boy apart.

While reviewing the Thomas Adams movement with his new apprentice (OK he didn't call YLH that) he noted that he didn't know what this brass strip was for.


Well crap if he doesn't know... What's an apprentice to do?

Find out... er...

Soon!



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