Spring or no spring?

[brutusamiga]

I'm worling on an old English longcase movement.

On the photo you will see the count wheel. The lever above it doesn't always land in the middle of the slot in the count wheel causing the strike to go out of sync.

Above that lever you will see a threaded hole and next to it two holes. I'm thinking it's there for a reason. Is it possible that a spring must be there? If I add a spring with the slightest bit of tension on the lever the clock runs for weeks without going out of sync.

 

[novicetimekeeper]

That looks intriguing, I have never seen a spring there but then you don't see many clocks like that up close. Can we see the rest?

 

[brutusamiga]

As requested. These are some of the photos I took while disassembling the movement.

 

[novicetimekeeper]

Thomas Tompion?

 

[novicetimekeeper]

Ralph may have one, but I doubt many here have seen an extended run external countwheel london longcase in the flesh. I have but not close enough to make much informed comment. Pretty sure I haven't seen any with a spring assist though.

 

[novicetimekeeper]

Have you worked out what those two holes are at the top of the dialplate? Did it have an arch?

 

[DeanT]

If it is Thomas Tompion it won't be too hard to find a picture of a similar clock. All the pillars are latched so that would indicate its not a run of the mill movement. As Nick has indicated I suspect it has had an arch added at some stage indicated by the vacant holes.

 

[novicetimekeeper]

Here is an 8 day tompion. It has the same pillars as yours but being 8 day it has the countwheel on the greatwheel arbour which is the usual arrangement for 8 day external countwheels . It has no spring assist.

I notice this has latched dial feet, does yours?

Bonhams : A pre-numbered Thomas Tompion eight day longcase movement and dial in a later walnut case Thomas Tompion

 

[novicetimekeeper]

This one although a completely different movement has a number of similarities. Same hands? Same wheatear engraving? Same chapter ring?

No spring assist.

https://collections.rmg.co.uk/collections/objects/79629.html

 

[brutusamiga]

This is an 8 day Tompion. If there shouldn't be any spring assistance, the question is why it works fine with the spring on the count lever and what I should do to make it work without a spring...

The count lever is supposed to drop into the middle of each slot on the countwheel. It doesn't do that at 9 o'clock. It rubs against the shoulder of that slot and jumps out without spring assistance. The countwheel was not altered in any way and I don't plan on altering it. Parts don't grow

 

[novicetimekeeper]

interesting that he went for a separate arbour for the countwheel then rather than mount it on the greatwheel arbour if it is just 8 day, but it must be a simpler arrangement to have it separate. I have seen that on a Dorset clock that was just 8 day too.

There are quite a few online but not many show the back of the movement sufficiently to see if they have spring assist.

 

[brutusamiga]

Sorry, it's a 30 day clock and not an 8 day.

 

[novicetimekeeper]

Sorry, it's a 30 day clock and not an 8 day.

That makes more sense, it it numbered or pre numbering? Are the dial feet latched? Got a case?

 

[brutusamiga]

The movement is unmarked and not numbered. Yes, the dial feet are latched.

Any idea why it works fine with the assistance of a spring? I'm a bit lost as to what else I can and must do here.

 

[novicetimekeeper]

The movement is unmarked and not numbered. Yes, the dial feet are latched.

Any idea why it works fine with the assistance of a spring? I'm a bit lost as to what else I can and must do here.

Sorry, I'm a collector rather than a repairer. I often find a bit of judicious bending sorts out the minor glitches though.

 

[Uhralt]

The movement is unmarked and not numbered. Yes, the dial feet are latched.

Any idea why it works fine with the assistance of a spring? I'm a bit lost as to what else I can and must do here.

Take a close look at the top of the lever, under magnification if you can. Are there any traces of rub marks? That would indicate that indeed there was a helper spring at some time. If there are none, check if the lever falls freely. If its pivots have been oiled the oil might have gotten sticky. They should be left clean and dry.

Uhralt

 

[shutterbug]

If there was a helper spring, I suspect it would be between the plates. I've seen them like that on similar count wheel designs, but am not familiar with that particular one.

 

[gleber]

Is the count wheel loose on its arbor? If so, it might allow slightly different orientation at different times and the slot may be off a little left or right?

Tom