clockmaker tales: Westminster chime

I struggled with the repair of this clock for too long. Every time I thought, this is it. I can't do anything more, this clock will run, strike and chime perfectly, only to be disappointed. The chime remained sluggish.

the Westminster chime table clock

It had been running well, the client said, but the chime was irregular and unreliable. I examined the clock at the client's home and immediately gave him my expert opinion. A previous clockmaker had done a botched job on this clock by taking the pendulum out for some reason and putting a platform escapement in. Rather clumsily by the look of it.

the platform escapement placed vertically on the back plate

Well... the clock ran and struck fine after my repair which included getting the platform escapement serviced as one of the balance pivots had been broken off. Amazingly, the clock ran happily even before my repair despite the balance swinging on only one pivot! The Westminster chime, though, was the real problem. It just would not run fast enough. Indeed, the whole point of my repair was to fix the chime.

Yet, I was making no progress whatsoever. Whatever, I tried. On top of that, the sound of the gong was pretty horrid. Then I noticed a sticker in the back door of a previous clockmaker (about 18 years before) who happened to be one of my tutors at West Dean College! When I got in touch with him about the clock, I asked him why he had replaced the pendulum with a platform escapement? To my surprise, he said, "look carefully at the plates, there are no holes for a scape arbor. So a pendulum was never meant for this clock." And he was right. This obvious was a model where perhaps the client could choose between a pendulum and a platform escapement clock.

Fixing the chime

I increased the end shake in the chiming train (which was tight). It did not help. I replaced the chiming main spring which was definitely needed. No improvement. Where then was the friction that caused the chiming train to be so slow? Should I use an even stronger spring? Where was the power lost? I could not find it, until I decided to take the clock out of its case for the fourth time.

I decided I just could not return a clock to the client in this half-baked state. Moreover, the costs had run up substantially already. It would be completely unethical to return a clock where the original problem of a lousy chime had not been properly addressed.

Then by sheer coincidence, I noticed two faint dents on the inside of the dial in the case next to the centre arbor hole.

two faint dents visible on inside of dial just top left from the centre arbor hole

These dents came from the rack stud and (eureka!) from the quarter chime arbor pushing into the inside of the case. A further inspection showed that the frame brackets that connect the frame to the inside of the case were held between the front plate and two nuts sitting on top of each other. Would it be better, perhaps, to put the frame brackets between these two nuts, so that the frame would sit a bit further away from the inside of the dial? This turned out to be the answer. The quarter chime arbor now no longer rubs against the inside of the case. The chiming train flows so happy and elegantly. It is delight to listen to this Westminster chime now (for some at least).

So, I bring the clock proudly back to the client. He is so happy and all seems well. Then I find him the next morning on my answer phone at 8:14 am. The Westminster is out of order. I explain that Westminster chimes are self-regulating and that after a few quarters the chime will come back to how he expected it to be. I can hear in his voice that he is not buying my bluff. So I promise him to examine that what I said is true and to call him back if I am wrong. Two minutes later, I call him to say that he was right and I was wrong. As the music phrases taken from Wikipedia below show, the Westminster chime always sounds the same phrases at the same quarter. I drove up to his house, undid the chiming pinion to put it in tune with the correct quarters, and now—after a long saga—everything is hunky dory.