# Grandfather clock broken escapement



## Doug Ring (Aug 6, 2015)

Hi all, new to this forum and clocks in general, but I thought I'd just plunge straight in asking for advice... hope that's okay.

I had to take our grandfather apart recently after it began chiming non-stop. I can figure out mechanical things to some extent, so I found it was a misplaced spring on the arm that falls onto the snail and was able to fix that. While I had the movement out I thought I'd look at the escapement wheel since the clock has always had a habit of stopping every few months, and found it was out of true.

Sadly though when I applied mild pressure to see if it could be gently bent back, a section of the wheel broke off - four teeth in total. There was solder on the broken section which suggested this had been a previous repair. It's not surprising it broke because there's very little contact area for solder to adhere to.

Any advice on my options here? Should I attempt to repair the original wheel or would I be better off sourcing a new one? If the latter, where would I find one?

Thanks for any help.

Doug.


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## harryblakes7 (Oct 1, 2010)

Hi Doug,

Interesting problem.......... ideally the wheel should have been warmed up to take the temper out of it to make it malleable.......

The wheel itself is designed to be thin with the minimal amount of metal between the centre and outside, this is due to reducing the inertia of the train, as it speeds up and stops at every impulse.

The escape wheel will be of two designs, either re-coil escapement, or dead beat escapement, the profile on both the teeth and also the impulse faces of the anchor lever will be different.

Ideally you need the old wheel repaired, usually with silver solder.......To have a new wheel made to the exact diameter of the old one and set up is quite complex.......... good lathe work combined with deep mathematics is involved.......... there is no "standard" size of wheel, you would basically need to make one from a brass blank like they were originally made 100+ years ago..........So, best bet is to repair it.......

If the clock movement itself is quite old, then the gears may have the teeth cut by hand, this then means that they need to mesh exactly as they did before being taken apart, otherwise the clock may well stop due to the teeth being too close together on one side of the wheel and too far apart on the other, unlike machine cut where the teeth would be cut exactly equal distant. So your going to need to have it running on a bench for a few weeks to ensure it ticks ok, if it stops mark the position, strip and move the wheel around a few teeth and have another go!!

Best of luck!!


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## vinn (Jun 14, 2015)

good advise; are you shure the original repair was soft solder? if you can clean that off, silver is the answer.


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## Doug Ring (Aug 6, 2015)

Hi guys, thanks for the replies and advice.

You make an interesting point Harry, that the wheel needs to be as light as possible to reduce its inertia. One thing I thought about doing was fixing a blank wheel to the face of the escapement wheel so that I could then fix the broken part to the blank, but that's unlikely to work given what you've said. Joining the broken bit with solder is a bit beyond my skills - I've soldered up lots of electronic projects in my day, but this is obviously another ball game. It's a recoil escapement by the way. I'll try to get some photos up.

Vinn, I've got very little experience with clockmaking or mechanical engineering, so I don't know what type of solder was used - the photos may clarify...

Okay, I have photos but I can't see how to post them... any advice on that, please?


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## Doug Ring (Aug 6, 2015)

So I can't seem to add photos directly to this post, but they should be viewable here:

https://plus.google.com/107286449430202140760/posts


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## vinn (Jun 14, 2015)

A mazing! i know how to solder and silver solder, but not how to post a photo. - for the time being -- dont worry about MECHANICAL EXPERIENCE. find a friendly clock repair man -- and learn how to solder with a mini torch AND keep on collecting. "carry on gridley"


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## Doug Ring (Aug 6, 2015)

Did you see the photos from the link, vinn? Does it look from them like this isn't a job for a novice? I'd like to tackle it myself just to be able to say I did it, but if I'm likely to screw it up through lack of experience I'll definitely look for a professional as you suggest.


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## Doug Ring (Aug 6, 2015)

So I found this online http://timesavers.com/i-8948780-tall-case-escape-wheel-hub.html It looks almost identical. What would be the practical difficulties of replacing the broken one with this?


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## vinn (Jun 14, 2015)

its not just a case of interchangable parts. among other things, fits and clearances. you might find a book on the web " basic clock repair" and many how to books. see how to do a total tear - down. dont be discouraged, wear safety glasses and be ware of the spring.


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## Doug Ring (Aug 6, 2015)

Okay, thanks again vinn. I never thought this would be an easy repair, but I like a challenge! I'll do some more reading. By the way - no springs - this is a weight-driven clock.


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## harryblakes7 (Oct 1, 2010)

Hi Doug, i would get some scrap brass and practice soldering, with a soft solder and plenty of flux. Then polish up the brass on the wheel and have a go at soldering it into position, clamp the old broken pieces together, then just flash the blow torch over and apply a small amount of solder.

As already said it wont be an "identical" wheel, teeth spacing and geometry is all super critical....... Even if it was identical you would have to drill out the centre of the wheel to make an interference fit onto the new arbour, which involves a lathe........otherwise your not going to get an exact centre and the wheel will rotate off axis and the clock will stop.....

In any event that new wheel is a 30 tooth one, designed presumably for a vienna clock. your clock should be a 36 tooth wheel, with 7 and a half teeth spanning the impulse lever with a 4 degree impulse angle / plane on the lever

You have two choices, either re-solder, or send the complete wheel away and have a new one made from scratch ( keep your credit card handy............ )

Have fun


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## Doug Ring (Aug 6, 2015)

Hi Harry, really useful post, thanks so much.

As I said earlier, I've had lots of experience soldering electronic parts, but I'll need to practice silver soldering before I do anything else to the clock. With a bit of practice I don't think it's beyond me to fix the old wheel, my main worry is how to support the broken part in exactly the right position. I have some mini-vices, but the practicalities of doing it escape me at the moment (no pun intended!) I feel I'd need to remove the escapement wheel from the shaft to solder the broken section in. "Interference fit" is a new term to me, but I looked it up... so I would assume that to remove the old wheel I should gently warm the boss and slide it off the shaft?

By the way, I counted the teeth on the old wheel and there are 30. The second hand is attached directly to the escapement shaft, and the pendulum beats in seconds, so if the wheel advances by half a tooth every beat, it takes 60 seconds for a complete revolution... is that not right?

Failing all that, ordering the new wheel may be worth a try, wouldn't you say ... it's not exactly expensive, and if I was REALLY lucky the internal boss diameter may be the same as the old! I almost feel that for me, setting the clock up with a new wheel (and one that won't possibly break in the future) would be easier than repairing the old wheel... but then, I don't have the years of experience you guys do.


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## vinn (Jun 14, 2015)

all good advice. you might find a video of how a clock is disasembled. its a long way to runing a lathe,but its a start. good luck


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## harryblakes7 (Oct 1, 2010)

Thanks Doug, well trying to guide in the right direction.........

If the clock has a seconds beating pendulum then it will be a long pendulum, 3-4ft long?

Yes thats right with the 30 teeth 60 seconds, some clocks may display a 60 seconds dial, but actually beat 54 seconds for a full minute.

Warm the boss by having it warmed up under the grill rather than using the flame of a blowtorch, so it is a uniform heat and it should stop any damage to the wheel by uneven heating. Possibly better to remove it when cold by simply driving it off the shaft with a small press & holding tool. You need to measure the exact position of the wheel on the shaft, say 30 mm in, so you can put it in the same position when finished. It may be on there quite tight, so i would urge caution before using brute force.........

Best of luck!!

Staking set, my brain is on a go slow tonight......... in middle of moving house.........anyway have a look at this to give you an idea......

http://www.ebay.co.uk/itm/Vintage-Star-Watchmakers-Staking-Tool-Set-/271953753652?hash=item3f51b4f634


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## Doug Ring (Aug 6, 2015)

This stuff is gold dust Harry, can't thank you enough.

My clock has a 3 foot pendulum and definitely beats once a second - I've put a noisy quartz clock next to it in the past to help me estimate the accuracy of the escape wheel. Being an audio geek I can also put a microphone against it and record a minute's worth of ticking onto my computer, then I can see quite clearly which beats are off using the display. It's accurate to well under 1/1000 sec!

Like the tip about the kitchen grill! I've been browsing the web for a while for advice on using a staking set - nothing that really helps me so far, but I'm a patient man - I'll get there...

Thanks again,

Doug.


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## harryblakes7 (Oct 1, 2010)

Thanks for the kind words Doug, well everyone tries to help each other on this forum  :rltrlt:

Try practising with your staking set, if your going to get one......just trial and error, once your proficient you'll be away!!

Also some good clock repair books out there..........have a look on Amazon and ebay


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## novicetimekeeper (Jul 23, 2015)

As an aside ( I work as a physics lab tech so this stuff fascinates me) the original definition of a metre was the length of a pendulum for a two second period.

Somehere along the line they got separated as that's 994 mm now.


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## Doug Ring (Aug 6, 2015)

Very glad of the help Harry. I'm an audio professional so I hang about those forums too - I try to be as helpful there as you've been to me.

So what's the definition of a metre these days?


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## novicetimekeeper (Jul 23, 2015)

The meter is the length of the path travelled by light in vacuum during a time interval of1/299 792 458 of a second.

http://physics.nist.gov/cuu/Units/current.html



That sounds unnecessarily complicated but the problem with the pendulum thing is that it depends on acceleration due to gravity, and that isn't the same everywhere.


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## harryblakes7 (Oct 1, 2010)

Really Doug?? I am well into my hi-fi........... looking to upgrade my amp to a devailet and also a Michell orb / sme4 / Lyra Delos :biggrin:

@ntk they have 4 second beating pendulum clocks at the Greenwich Observatory........ also they have "played" with running pendulums in vacuums, along with the Janvier double beating pendulum which radiates energy to the opposing pendulum, keeping them both "in time", thats a physics brain ache...... :yes:

That is an interesting equation about the length of a pendulum as the mass at the bottom must make a difference as well as the impulse given. Both inversely proportional, so you could have a different "metre length" and it would accomplish the same. Ideally the pendulum rod must weigh as close to zero as possible then the weight mass, otherwise you lift the centre of gravity.

The old grandfather clocks used long pendulums to even out the impulse given as the wheel teeth was hand cut, so you would have irregular power applied to the escape wheel, the long pendulum evened that out.......


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## Doug Ring (Aug 6, 2015)

So... you'd need to be pretty quick on the stopwatch for that then, Novice? (may I call you Novice?  )

Yes, it's a bit of a brain ache - especially for an antique clock where you'd be grateful if it was within a minute a week...

You've got some cash kicking around if you're after these bad boys for your hi-fi Harry. I had my ears syringed recently and did a quick test on my hearing afterwards - it doesn't go much above 10kHz these days so I can save lots of money by not having to upgrade any more! Lots of old British kit here though, Quad, Tannoy, B&W, Audiolab... and a recently-purchased beautiful little Marantz CD/network player/internet radio/power amp which hardly qualifies as hi-fi but is just a joy to use. But being an ex-BBC engineer and part-time musician I have a lot of pro kit lurking about too... still hanging on to my Revox A77... which is of course built like a Swiss clock...


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## vinn (Jun 14, 2015)

what is the conversion factor to convert a meter into ---- " furlongs per fortnight"


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## Doug Ring (Aug 6, 2015)

Hold on Vinn... you can't convert distance into speed!

When I used to fill out recording reports for radio programmes we'd occasionally have fun with the box for "Tape Speed." Instead of 7.5 or 15 ips, we would actually put in the the calculated figure for "furlongs per fortnight!" Another favourite was "megatons per four-minute warning," or the even more bizarre "Hampdens per match..." :biggrin:


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## harryblakes7 (Oct 1, 2010)

You have a Revox A77 ? Jealous............I actually want to get a Pioneer 909........ stunning......... my old Grundig has died the death........

Surprisingly the old cassette can still throw some surprises when using a Nakamichi Dragon / CR7e............... If you have any old BBC SME broadcast decks let me know..... :laugh:

Anyway, how is the broken escapement wheel? Have you done any experimental soldering yet?


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## vinn (Jun 14, 2015)

doug; thanks for the correction. ill take the blindfold. by the way, the key to SOFT soldering is the tinning fluid. zinc and hydrocloric acid -- in the proper proportions.. tinning fluid may be illegal now,but -- schooling on this subject is recomended.


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## Doug Ring (Aug 6, 2015)

The A77's a nice machine Harry, but the much later B77, which is a fully-fledged professional machine, beats it hands down. They shouldn't be too hard to find because they're so big nobody wants them. That doesn't seem to apply to broadcast turntables however... no matter the size they're going for crazy money nowadays. I never saw any SME decks in use though - when I started back in the 70s it was modified Garrard 301s with a crazy motorised cue start system; after that came Technics SP10s with a custom-designed arm; finally it was a complete turntable-and-arm unit from EMT.

So... erm... bit off-track - back to clocks... turns out I have a friend who used to do jewellery work as a hobby and has done lots of silver-soldering. This is a guy who loves a challenge, so he's going to help me fix the escapement. I'll try to take photos of the work in progress and post them for you.

Thanks for all your help and chat, guys.


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## Doug Ring (Aug 6, 2015)

Hi guys, bet you all thought I'd died... or given up and gone to a professional repair shop. Well, a lot of life stuff got in the way, but I'm pleased to say that a few weeks ago my friend came through on the repair job. Since you've been so helpful on here I thought you might be interested to see how we did it.

At first I thought we'd get nowhere, because when I tried to clean the solder off the broken piece seen below it turned out that it wasn't a single 4-tooth segment, but two pieces with two teeth and a wire along the bottom edge! I panicked a bit at this stage, but my friend assured me he could still do it - he also does railway modelling and had some very thin brass strip that he was able to form into a proper arc the same as the internal diameter of the wheel. Then he drilled a hole the same diameter as the escapement wheel shaft in a vermiculite block and dropped the shaft in. That held it pretty securely and he could then carefully arrange the flux-coated pairs of teeth and the brass strip on the vermiculite surface. He then applied the solder wire, blasted it with a gas torch and all was good!

He actually used lead solder, which surprised me, but it seems strong enough. We also felt we should add a balancing strip on the opposite side of the wheel for good measure. You can see the strip holding the teeth in the photos below; the balance strip is just visible at the top of the pictures.

It was a fiddly job to get it back together and I wasted some days trying to regulate the pendulum before I realised that the friction mechanism driving the minute hand was slipping - it had got oil in it... d'oh! Now she's ticking away better than before and keeping not bad time for an old lady!

My friend went away with a bottle of Macallan single malt whisky as a token of gratitude, but all I can offer you folks on here is my sincere thanks for your encouragement and help. I'll know where to come next time!


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## mel (Dec 6, 2006)

Looks a pretty good job to me - - :notworthy: - - and one that follows a fairly good repair principle, fix as little as possible if you're dealing with "fragile" parts.

Report back on progress as to how well it's doing! <-- This is required under TWF rules :yes:


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## Doug Ring (Aug 6, 2015)

Hi Mel... I'm in Edinburgh too... what are the odds?! Well I've had a radio-controlled digital clock sitting next to the grandfather for the past week or so, just checking for accuracy. I'm can't remember how accurate she used to be, or what to expect from a clock this old, but I can probably get within a minute a week... however good or bad that is. She lives in the hallway where the temperature isn't too constant, so with a simple steel-rod pendulum I imagine she's quite susceptible to temperature variations. Even so, it's just nice to have her working again.


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