Mantle clock stops – interfering gears?

[Chris Barrett 1Participant @chrisbarrett1]

My previous post on this forum solved one problem – minute hand slipping – the cure was to compress a star-shaped spring. Thanks for this advice.

But now there's aother problem. The clock movement was running well for three days continuously – I was regulating the pendulum length, while I could observe it running, before putting it back into its case. Then it suddenly stopped.

The cause was that there was no drive to the escapement.
The gear that drives the escapement overhangs the large gear which contains the drive spring.
There is a small amount (approx 1mm) of end float in the bearings of this gear which drives the escapement. If it moves towards the front of the movement, it rubs against the large gear. The teeth on the smaller gear had snagged against the teeth on the large gear, and this stopped it turning. So there was no drive to the escapement, and the clock stopped. Nudging the small gear towards the back of the movement, freed it from its interference with the large gear – and the clock started working once more.

So my question is – how do I stop the smaller gear moving forwards and jamming with the teeth of the large gear?
Would tipping the clock slightly – so that the front is higher than the back – stop the small gear from moving forwards and jamming?

Any advice would be very welcome. I apologise for not using the correct technical terms – I am an engineer, but am only slowly starting to learn about clocks.

[Chris Barrett 1Participant @chrisbarrett1]

[Brian HParticipant @brianh50089]

Is it possible to add a spacer (washer) to take up the play?

Brian

[Fowlers FuryParticipant @fowlersfury]

No apologies needed for non-horological terms ! However on the basis of your description it's necessary to make some guesses/assumptions which could well be wide of the mark.
If the pivot on which the offending wheel (gear) is mounted moves excessively between the clock's plates then the pivot hole (is this what you mean by bearings?) in one plate has become enlarged. Correcting that will require some major surgery as you would need to remove that plate and either put in a bush or adopt the bodgers-dodge of tapping around the hole to close it slightly. In either case you will need a suitable broach and maybe a oil-cup tool .The final hole should not have a parallel bore but be like
this:-

Tilting the clock will achieve nothing.
Yet "approx 1mm end float" may not be that excessive – are you sure the wheel is firmly fixed to the pivot ?
But all the foregoing doesn't quite square with the fact the clock ran well for 3 days, unless perhaps the pivot hole aperture had previously worn very thin and just quickly 'gave way'.

[Mick B1Participant @mickb1]

Might you be able to make or find a 'C' washer that you can snap onto the pivot of the wandering component to constrain its movement?

I was thinking of something like what was sometimes called an Anderton clip – though I guess you'd have to be pretty cute to make one, or pretty lucky to find one, that'd fit. But it might save some tricky assembly work if you could.

[Chris Barrett 1Participant @chrisbarrett1]

Thanks for the various bits of advice.

 

I came up with an alternative solution. I glued a small washer to cover the end of the pivot hole, to stop the gear from moving too far forward and clashing with the large drive spring gear. See picture 1. This solved the problem of the gears clashing.

But then I discovered the reason for the gears clashing – oddly, I had not noticed this before. See picture 2. The drive spring casing, and the gear behind it, is tilted backwards. The top of the large gear is nearer the back of the clock than the bottom of the gear. You can see how little clearance there is between the two gears, even with the small gear pushed back by the glued washer.

Should I be worried about this?

 

Edited By Chris Barrett 1 on 03/10/2018 16:03:13

Edited By Chris Barrett 1 on 03/10/2018 16:04:08

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Chris Barrett 1 on 03/10/2018 16:02:04:

Should I be worried about this?

.

Assuming that the clock was not built wrong … It looks like it has had a long, hard, life !

It may limp on for another decade or so, but it's certainly not right.

You will probably find that the barrel arbor pivot, and/or its hole are badly worn:

… This is a very good time and place to learn how to re-bush holes.

MichaelG.

[BazyleParticipant @bazyle]

This movement is a very common design with a moving barrel so the main winding arbor turns as you wind it so you can see if there is any wear at the rear which is where the force of the interaction of the wheel and pinion acts more than the front. It is probably fine. Then you can try moving the barrel relative to the arbor to see if the wear is at the centre of the main wheel (most likely as it rather inaccessible for oiling, though it is doubtful the clock has ever been oiled.

Most likely it has come to light because the frame has been distorted slightly during the recent manhandling. You should be able to work out which way to thump it to free it up a bit.

[Michael GilliganParticipant @michaelgilligan61133]

Chris,

I was looking for something else, and found this: **LINK**

Why I Wont Be Servicing Your Clock For £40! How to Service a Smiths Clock.

You may find it useful.

MichaelG.

[Chris Barrett 1Participant @chrisbarrett1]

What a wounderful, comprehensive write-up!

Thanks, MichaelG!

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