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.

The arrogance and the double count wheel

The client of the American clock I repaired a few months ago called to say that his clock still did not strike the hours consistently and correctly. I had poo-pooed his feedback the first time (in private to my wife) saying that this client just did not understand how to adjust the clock to winter time and that therefore he must have put the hands backwards when winter time was introduced in October and now the hour hand was out of sync with the countwheel.

To prove my point I took the clock back (it was still under warranty), hung it in my workshop and noticed how it struck the hours beautifully and consistently but always one strike more than the hour. Hence, I told myself, this was a simple case of lifting the locking detent 11 times so the clock could strike the hours 11 times quickly to end up in the correct position so it would strike the next hour correctly.

I did exactly as planned, noticed that the striking was again in sync and returned the clock to the client triumphantly with a little note how to adjust the hands at the time of a summer time-winter time switch-over and vice versa. All for free, of course, under the warranty.

Was it irritation or surprise that I felt most when a week later I ran into the client who said the striking was still off. I asked whether the clock was hanging skewed on the wall for want of a better question. The client, though, suggested I had another good look at his clock. I was indeed keen to examine the clock because I began to realise that more was at work here than a client who did not know what to do when winter time came along.

So, I opened the case and took a proper look at the countwheel and noticed that the countwheel had two sets of 1 to 12 divisions rather than one! Examining both sets closely, I noticed that the second set showed the number 2 strike area slightly bent toward the number 3 area which meant that the locking detent did not fall into the number 2 hole. That resulted in five strokes at 2 o'clock! So, I bent the number 2 area straight. Now the clock strikes the hours perfectly on both sets of 1 to 12 on the count wheel.

I am hanging on to the clock a little longer in my test room just to check the correct number of hours is being struck. I do not want to hear the client tell me for the third time the clock does not strike properly! My arrogance had clearly blinded me to examine my own work a bit more closely before drawing conclusions. At least, I now am on alert when a two set countwheel lands on my work bench!

Comtoise clock - My family member

It is only when my favourite client called that I realised how closely connected we remain to what we have repaired. It feels as if all the clocks that have passed through my hands are part of my family. This client is a favourite of mine for a variety of reasons. He is erudite and speaks such beautiful English. That certainly endears him to me, or is it me to him?

His clock was the first mechanical clock I repaired for a client in my career which must create a special bond. The client proved elated with the report I produced when I brought the clock back. He showed it to his wife and friends. I know this, because I was there hanging the clock back in its case when this all happened. It made me feel particularly important when he introduced me to his friend as "my friend the professional clockmaker".

The clock in question happened to be a Comtoise. The client told me how he had purchased the clock in an antique shop in France and how the owner of the shop had told him the story of how Comtoise clocks were produced and sold by itinerant salesmen who carried a frame on their back into which several Comtoise clocks would fit. They would walk to the next village and start selling them. The pendulums would be folded on their back. Hence we still see Comtoise clocks with pendulums that fold into several pieces of about 20cm each. Once a clock would be sold, the wandering salesman would walk with the client to the nearest blacksmith to get the weights made then and there. It being impossible, of course, to take the weights for nine clocks or so along on your back.

Comtoise (or also called Morbier) clock

I had never touched a Comtoise clock but had heard my co-students on the clock course at West Dean College talk with respect about these French clocks. I was amazed how different they were from the inside from the clocks I had been working on until then. I began to love the Comtoise design and its well established "tick" and loud bell. We became good friends: the clock, the client and I.

I give a 6 months guarantee on my work and it was therefore with mixed feelings that I heard my Comtoise client ring on Saturday morning clearly with pain in his voice. Would his wife have died? Not so. His clock has stopped and could I come please to have a look? The warranty period had elapsed but still it hurts your pride to have a client tell you that a clock you worked on has come to a halt. I spent the rest of the weekend thinking about the clock. What can it be that stopped it? I had thoroughly checked everything and then tested it for two weeks before handing it back?

He called me again this morning saying he noticed how the minute hand had become entangled with the calendar hand and how he had managed to disentangle them. The clock was working fine again and I did not need to come.

End good, all good. It would have been nice, though, to see the clock again.

Striking tips

I learned two things today.

I must show my clients in my written reports, which they get when I give them their repaired clocks back, how to set the time. Time setting on clocks can differ greatly between clocks. On some clocks you can happily (though gently please) push the minute hand past the half hour or hour—whichever comes first—without bending or breaking anything in the clock. On other clocks you can't. You will have to wait until the clock completes any striking before pushing the minute hand further.

On top of that, it turns out that some clients get into trouble during the switchover to winter time. For instance, on count wheel striking clocks, they push the hands backwards an hour and then discover that the hands are no longer in sync with the striking.

From now on, therefore, I would do well to add an Appendix to my reports explaining to the client how to set the time on their particular clock. This should help prevent getting clocks returned to me that are perfectly fine but for the striking being an hour ahead.

The second thing I learned today is that when you have put a complicated clock together and you notice that the bell hammer—in rest position—is not sitting perfectly between two pins on the pinwheel, then there may be a more efficient way of resolving this than taking the clock plates apart to adjust the pin wheel. I noticed that I could take the gathering pallet off the gathering pallet arbor, and

• then put the pinwheel in the right position vis-à-vis the bell hammer, so that the bell hammer is exactly in the middle between two pins when the striking train is at rest position, while also ensuring that the warning pin on the warning wheel is in its stop position, and
• then put the gathering pallet back on its arbor also in rest or stop position.

That solved the problem nicely and efficiently in about one minute and with a lot less risk to any damage to the clock compared with taking plates apart and moving the pinwheel a few teeth.