Struggling with the mainspring of a fusee dial clock

I just completed my first clock with a fusee. It was a rather dilapidated English dial timepiece. Once I cleaned and repaired it, it came into its own beauty, though, even after agreeing with the client to leave the dial in the worn state it was in. So a real conservation project.

English dial timepiece with fusee inside

It was clear to me that the mainspring had seen better days and remembering my West Dean tutor's helpful rule:

when a mainspring's diameter is equal to or less than twice the diameter of its barrel, then replace the mainspring,

made me decide to replace the mainspring. I ended up with a stainless steel mainspring supplied by Cousins. It was the first time that I had to apply my tutor's rule, so my expectations were high of the performance of this new spring after I had put it into its barrel and put a new steel wire onto the barrel and fusee.

I should have been for warned, though. Putting this stainless steel spring into its barrel was a tour de force! After several tries with the first aid box placed close to me, I managed to get the mainspring into the barrel. Once the barrel was in the clock, I tried winding it. It proved impossible to wind the clock more than two half turns. I just did not have the power in my hands to do more. A blessing in itself, because otherwise I might have broken the key, the steel wire or both (at least it felt like that).

Luckily, in the same week, the Annual General Meeting of the Antiquarian Horological Society was about to take place with this year's focus on Dutch clocks from the 17th and 18th century. In other words, I had to be there. Two of my West Dean classmates were quick to solve my mainspring problem at this meeting by recommending I try a carbon steel spring from Clockspares. Carbon steel springs having much less power than the stainless steel variety. This solved my problem well. It even allowed me to put gut line on the barrel rather than steel wire.

This whole saga taught me to include mainspring data in my written client reports. And with further help from this informative website http://www.abbeyclock.com/usmsp.html I now have a much better handle on mainsprings.

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.

First quarter:	(1)
Half-hour:	(2) (3)
Third quarter:	(4) (5) (1)
Full hour:	(2) (3) (4) (5)
Big Ben

A clock with one winding hole that strikes the hour?

I comfortably walked into his living room and told the client "your clock is non-striking, so how can you complain that the striking isn't working? Here look, there is only one winding hole". The client then pointed to the bell, hidden at the back. I was in shock.

My reputation was no longer at risk, it had disappeared as fast as I had entered the room. The client then proceeded to explain that this Swiss Neuchâteloise clock only has one winding hole to achieve two things: it winds the clock and it winds the bell! But how? With only one winding hole?

Neuchâteloise clock

Only when I opened the clock, did I discover the sophistication and reliability of this Swiss design. A little toggle containing two wheels  will switch which train you are winding depending on whether you turn the winding key to the right or the left. See picture below. The toggle with the two wheels sits just below where the word Zenith appears. How ingenious!

the one winding hole toggle allowing you to wind two trains

The beat regulator on a French clock

Although they are delicate to repair, I always tell my friends and anyone who wants to listen that French clocks are all the same. They seem to have been made by one and the same cookie cutter, or rather French clock cutter.

However, working on my 90-year old aunt's clock revealed two novelties for me. First the crutch has a rather clever horizontal lever sticking out to the left (see picture below) with which one can regulate the beat of the clock.

Getting a clock into beat by bending the crutch I still find a difficult operation until this day, as I my intuition never seems to guess the direction right into which to bend the crutch. I know this is not a job necessarily suited for the intuition, but having asked my brain for the answer several times now, it always gives me the wrong answer. So, my aunt's clock has this clever horizontal "beat regulator" attached to the bottom of the crutch. You simply twist the knob at the end of the device left or right and hear what it does to the beat until you get it precisely to your liking.

The second oddity I found with this clock, which is not as helpful a device as the beat regulator, is a pillar pin that does not fall over the back plate of the movement but into it. They must have decided that the pillar could not protrude through the movement far enough to fit a pin through that would rest on the back plate. That then left as only option to push the pin through the end of the pillar and into the plate. Neat and never seen before.

The mystery of left and right winding holes

Her arthritis is too serious to wind her Victorian black slate clock herself. She asks the cleaning lady to do so. The beautifully crafted Winterhalder and Hofmeier chiming and striking clock in the corridor leaves her cold. I must have been called back at least three times after I repaired her Victorian black slate clock  (see picture below) because it had stopped. How is that possible? I gave it my everything. I cleaned it according to the high West Dean College conservation standards. Only white spirit as cleaning fluid, pegged out all the pivot holes, checked all the wheels and pinions meticulously, checked the endshake, the depthing of each of the three trains, wheel pair by wheel pair, rebushed where needed and paid great attention to detail, repairing and improving a few minor things along the way. After the repair, I had it on test for two weeks in my workshop. And it all ran fine.

black slate clock

Yet, the call of an 80-year old for help with clearly something that is so dear to her that she does not want to know about the beauty of her Winterhalder and Hofmeier, moves me enough to get up from my bench onto my bike, down the hill to her care home. Am I doing this, because my parents are equally old and dependent on others, while I am too far away to do this for them? Is this a guilt trip?

I know she has someone to wind her clock now. Luckily, she lives around the corner, so travelling to her place is easily combined with running an errand in the village. I have been there several times now to discover that only the striking train had been wound!

Learning point: Clearly, I have not paid enough attention to explaining the very basics of setting time, winding a clock, the difference between the left and right (and sometimes middle) winding holes, how to start a pendulum swinging again. In my written reports, I explain some of these things, but who reads them? A one-to-one client clock debriefing really needs to become part of my routine. Sitting down with the client when I bring the clock back after a repair to talk them leisurely through all the things that are important to keep the clock running. Besides, these short meetings, sometimes hit on the very things life is all about. In talking my 90-year retired actor clients through my conservation report of their grandfather clock (which he, by accident, had knocked over when rushing to the phone—during an acting lull—in the hope there was another gig on offer) we ended up singing "My Grandfather Clock" together around the coffee table:

My grandfather's clock

Was too large for the shelf,

So it stood ninety years on the floor;

It was taller by half

Than the old man himself,

Though it weighed not a pennyweight more.

It was bought on the morn

Of the day that he was born,

And was always his treasure and pride;

But it stopped short

Never to go again,

When the old man died.

I am blessed to be a clockmaker.

Carriage clock with alarm quirks

I am working on a beautiful carriage clock or should I say timepiece because it does not strike. But it has an alarm. The alarm mechanism is extremely sensitive to the correct springiness in a thin rod-spring (see picture below) that releases the alarm.

It took me quite a while to figure out how to get the alarm right and where to focus and intervene to get it to work reliably. I must make a point to explain to the client that alarms are finicky and have a character of their own. The slightest change in the springiness of that rod-spring can silence the alarm forever or, worse, keep it running until the alarm spring is fully unwound; after which winding it may no longer be possible because the rod-spring will not lock the alarm arm any longer. I wonder if this rod-spring is so sensitive that a change in temperature or humidity might already cause it to malfunction? Or, could it be hysteresis? In other words the sheer fact of the spring being pushed repeatedly could make it less springy over time.

I was so pleased that I got the alarm to go off reliably after quite a few trial and error iterations. So, I put the carriage clock together again with a feeling of great satisfaction that another clock can go to the test bench for about ten days before being returned to the client. And, once that happens, getting paid!

So my frustration was hard to control when I had the clock all finished and in its case again to only notice then that if I set the minute hand to time the alarm hand would move along. Why on earth was this happening? It couldn't possibly be a feature of the carriage clock? So what caused this?

I took the whole clock apart again and started burnishing the stud on the alarm setting wheel that rubs against the alarm setting disc (see picture below: the alarm setting wheel is second from top left, the disc is just below it). I assumed there was too much friction between the disc and the stud.

After a while I noticed that the alarm setting arbor has a four armed friction washer (see picture below: the four armed friction washer is just below the number 390) pressing against the inside of the back plate.

This washer must be there to introduce sufficient friction for the alarm hand not to turn along with the minute hand when you are setting the minute hand to time. While, when you set the alarm, this washer must not have enough friction to prevent you from turning the alarm setting arbor. So again we seem to be working here with a part that is ever so finely balanced. I can already see more trial and error iterations coming!

I then noticed that this friction washer which looks like a starfish was doing a miserable job. It just hung there on the arbor flat as a pancake, while it should be pushing the alarm setting arbor away from the back plate. When it does that properly it will create minimal friction when the alarm setting wheel stud travels over the surface of the alarm setting disc.

So now, my next move will be to either bring life back into this washer by hammering it convex again, or make a new one and then see if the alarm hand will stay put when I turn the minute hand.

To be continued.

Drilling small holes with a tungsten carbide drill

I have been drilling a hole of 0.35 mm diameter to re-pivot one of the pivots of the contrate wheel arbor of a miniature carriage clock. The diameter of the arbor is 1 millimetre. It ended up in total failure. It was the first time I was drilling with a tungsten carbide drill. Or rather, tungsten carbide drills in plural. I went through about ten of the box of 50 before I gave up. They all broke in the arbor and I could not get them out anymore, let alone crush them to smithereens in the small hole. The hole was simply too small to do any crushing. Lesson learned: be ultra careful and ditto patient when drilling with tungsten carbide drills if they are that small.

I had to start again with a new arbor and pinion. I was determined to turn the pivots of 0.35 mm and 0.39 mm diameter myself. Again, I failed. I am sure it must be my limited skill in sharpening the tool I use on my watchmaker's lathe. I therefore turned it into an exercise of re-pivoting by drilling 0.45 mm (slightly larger this time) holes at either end of the arbor. I decided to make the pivot holes about 150% longer than what the length of the pivot should be. I made this 150% up as a good gut-feel number. I hope someone will come around and tell me whether this happens to be one of the golden rules of clock making, or, a violation of it. [Addendum: 30 May 2012: Today, an experienced clockmaker kindly explained to me that the generally accepted depth for a hole to repivot is two and a half times the pivot diameter, but that some clockmakers even go for three times.]

Just have the drill touch the arbor and just apply enough pressure to stay connected with it but do not push! Wait for some swarf to become visible then pull the drill slowly back out of what begins to be the pivot hole. Rub away the swarf, wipe your finger gently over the drill to wipe away any swarf sticking to the drill and start again. This way you advance about one tenth of a millimetre every 2 minutes. It does work. You get there in the end. I noticed that I needed complete silence around me because you want to hear the tip of the tungsten carbide drill make contact with the inside of the arbor. Once you hear that slight hissing sound you know that you can apply the minimum amount of pressure you can possibly put on. I was afraid to be disturbed by any unexpected sound around me. The carpenters at the neighbours seemed to have their day off, the children were still in bed, the wife had gone to work. Only the washing machine was spinning in the background which meant I could drill in between its centrifugal spurts.

I noticed that the deeper the hole the longer you will have to wait for swarf to come out. Do not become impatient if you do not see any swarf yet. It is easy, but fatal, to think that you are not applying enough pressure for the drill to do its work. "There is not any swarf, so I must press a bit harder!" Don't! Just sit patiently and wait. Swarf will come. And as soon as you see it, keep that same pressure going for a few more seconds and then pull the drill out again to clean away the swarf from pivot hole and drill and start again.

My turning speed was slow, the same speed at which I would turn steel. Perhaps the whole process can be sped up by increasing the lathe's speed. I did not dare to do this out of fear for breaking the drill which would undoubtedly (Sod's law) park itself in the arbor for good.