Odd clock problem

I have an old (Victorian) pendulum spring wall clock. I finally got it to keep good(ish) time by adjusting the pendulum length. Recently it has taking to losing 11 minutes then it continues merrily on its way not losing any more. It's always ~11 minutes (ie not 8 or 13). If I reset it, it will sooner or later do the same thing. Any ideas?

Reply to
Jim Scott
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Pendulum length is set correctly once only in the life of the clock. If it then drifts I would suspect friction due to muck in the mechanism, rust, things like that. It is better to clean rather than just oil, since accumulation of crap is too often the problem with old kit.

I've no experience with clock mending, but from working with other assorted historical mechanicals this is what I would suspect, rather than a pendulum length error.

Why would it lose at one piont and keep time the rest? Probably a bit of muck on only one part of a wheel.

NT

Reply to
bigcat

does it lose the 11 minutes over a 12 hour period or does it lose a bit at a time. I.E. 5 1/2 minutes over 6 hours. There could be a point where one of the hands is crossing over the other and at a specific point are misaligned just enough to bind up untill pendulum force causes them to snap into position. The binding hand could slip on it's axle untill the pressure was sudennly released. You should get a few Newcastle Browns and sit and watch it intently untill it happens.""Jim""

Reply to
Jim

does it lose the 11 minutes over a 12 hour period or does it lose a bit at a time. I.E. 5 1/2 minutes over 6 hours. There could be a point where one of the hands is crossing over the other and at a specific point are misaligned just enough to bind up untill pendulum force causes them to snap into position. The binding hand could slip on it's axle untill the pressure was sudennly released. You should get a few Newcastle Browns and sit and watch it intently untill it happens.""Jim""

Reply to
Jim

A pendulum will vary its length with temperature, enough to cause inaccuracy between summer and winter. A few have a compensated "gridiron" pendulum, but these are pretty rare (and most are just decorative fakes).

If your clock only ever jumps forwards or back by 11 minutes, then I'd suspect a loose hand. Does it still strike on the hour ?

If it jumps by this much but sometimes does it twice, then look for wear allowing endfloat in a pinion. Combined with a less than flat and perpendicular wheel, this may allow the pinion to jump a few teeth on the wheel. This same fault can obviously cause the "single jump" too, especially if it's freshly wound.

The most likely pinion for endfloat problems is the one forward of the mechanism's front plate, driving the hands.

In general, don't mess with any clock older than WW1. Menders are still around and they deserve the trade. If it's a post WW2 Smiths or Perivale, then get the spanners out and go to it.

Reply to
Andy Dingley

I have an old (Victorian) pendulum spring wall clock. I finally got it to

There is clearly a case for setting the clock 11 mins fast - when it will take to losing 11 mins. When it continues on its merry way not losing any more - the clock will be showing the correct time. My idea !

Pete

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Reply to
Peter Stockdale

Now that's lateral thinking. :o)

Reply to
Jim Scott

Timely, though.

Mary

Reply to
Mary Fisher

Is it a striker. Could be some problem in the cam area.

Reply to
Rusty

Yes - this appears to be 11 mins backlash in the mechanism. The pendulum timing seems to be OK, but 11 mins is being taken up by (probably) wear in the "cogs"!

Reply to
Frank Erskine

Or maybe its the OP thats losing 11 minutes, not the clock...

NT

Reply to
bigcat

Must be on whisky diet like me, but I lose days.

Reply to
BigWallop

or just stop it. then it will be right twice a day which is better than never being right having lost 11 minutes.

Robert

Reply to
robertmlaws

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