Clock problem, balance wheel

Jan 19, 2018 20 Replies

I have a 1 transistor balance wheel clock that gains 5 minutes a day. Repea ted adjustment over about 3 turns so far of the speed adjusting screw has m ade no noticeable difference. I can't tell which way the threads run on the screw, and thus which way I should be turning it, it's gone anticlockwise about 3 turns.



If all else fails I can always add weight to the wheel, but this ought to b e solvable a lot more easily & elegantly. What am I missing here?


NT


eated adjustment over about 3 turns so far of the speed adjusting screw has made no noticeable difference. I can't tell which way the threads run on t he screw, and thus which way I should be turning it, it's gone anticlockwis e about 3 turns.

be solvable a lot more easily & elegantly. What am I missing here?

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I had a remmington clock that did this, it in the end ended up in the bin. I have no real idea but I suspected that the and timing inside were erratic for some reason and hence no matter what you did it varied wildly. It could have been the escapement and gearing of course, but either way clocks of this kind are mega cheap.

I used to know a source for the actual mechanisms but they are no longer around. Brian

I never did figure out what the transistor actually did in these clocks , by the way. Brian

It's not erratic, nor is it cheap. It's a historic rarity. Otherwise I'd have binned it or fitted a quartz mechanism.

NT

snipped-for-privacy@gmail.com laid this down on his screen :

Gaining, usually means the balance wheel is not swinging far enough on each stroke. adding more weight will not help. That suggests the lubrication has dried out and become sticky. It needs stripping, cleaning and re-lubricating.

I have no idea where the transistor might be involved, unless that clock might be designed to be a master clock feeding other slaves, or its some fancy electrical winding/escapment mechanism.

Does the movement use an electromagnet?

Some background info here

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Patent 2942205 filed 1955 explains the transistor mechanism better than I can.

It hadn't occurred to me that stiffness might speed it up. Judging rather roughly by eye it looks like the balance wheel swings about a quarter of a turn in each swing. What would be a suitable lube?

NT

What does the adjuster do? Usually it shortens the effective length of the balance spring to make it go faster (I think).

Five minutes a day sounds like much beyond the range of the adjuster, so I think there must be something else wrong with it.

roughly by eye it looks like the balance wheel swings about a quarter of a turn in each swing. What would be a suitable lube?

Yet wikipedia says... "Balance wheels rotate about 1½ turns with each swing, that is, about

270° to each side of their center equilibrium position." I don't see how that would be compatible with the transistorised drive thou gh.

NT

Repeated adjustment over about 3 turns so far of the speed adjusting screw has made no noticeable difference. I can't tell which way the threads run o n the screw, and thus which way I should be turning it, it's gone anticlock wise about 3 turns.

yes, standard mechanism in that respect.

to be solvable a lot more easily & elegantly. What am I missing here?

Ah. I'll take a look & see if disassembly is something I could realisticall y do.

NT

Can you check the spring is free from fouling itself, or anything else?

5 minutes is a lot to lose in a day.

Also make sure there is no oil on the spring, if you've happened to oil the movement recently.

Seconded - I've known of problems with excess oil on the hair spring before.

I would give more attention to the hairspring, as mentioned lack of lub can shorten the beat also a spring that loses some `tension` will not swing as far thus shortening the beat making it go faster. If any of the `layers` of the spring touch one another that can also cause it.

There isn't a speed adjusting screw - you must be loosening the pivot screw which has a conical hole in the end in which runs the pointed shaft of the balance wheel. Any more turns and the wheel will fall out.

Speed is adjusted by moving the lever that has a slot constraining the spring. Move the lever to lengthen the length of moving spring to slow the balance.

The spring is all placed correctly, no fouling. I've not oiled anything and don't see any oil anywhere.

OK we have good news. Today it gained 10 minutes a day not 5. This means a) I've been adjusting it in the wrong direction b) the scope of adjustment does cover this much variation

NT

The ticking speed should not depend on the amplitude of swing. It's like a pendulum that swings less as the driving spring runs down, but maintains the rate. That's the whole point of a pendulum and gravity, or balance wheel with hairspring.

Repeated adjustment over about 3 turns so far of the speed adjusting screw has made no noticeable difference. I can't tell which way the threads run o n the screw, and thus which way I should be turning it, it's gone anticlock wise about 3 turns.

to be solvable a lot more easily & elegantly. What am I missing here?

and that spring restrainer is adjusted by a screw.

NT

Of course. But if a mechanical fault such as friction were reducing the swi ng greatly that could affect the period.

It looks moot in that I'm confident it can now be adjusted correctly. We sh all see whether it keeps consistent time, but it looks like it does, if so then the short swing is likely by design. I doubt wiki's quoted 1.5 turn sw ing would be compatible with the drive system.

NT

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