French mantel clock

Baz

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I have finally got a clock with a Japy Freres movement and I have pulled it apart to fix up an intermittent stopping problem. I consider that the problem is due to a dirty mainspring and it certainly was well gummed up when I got it out of the barrel.
I am seeking opinions as to whether it should be replaced since it has not expanded very much when released.
What do you think ?
Also what is the purpose of the bolt on 'shoes' on the back plate ? Did they add the feature to make it easier to reassemble ? !!!

Thanks, Baz
 

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Tom Kloss

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Baz said:
...Also what is the purpose of the bolt on 'shoes' on the back plate ? Did they add the feature to make it easier to reassemble ? !!!
Hi,
I'm no expert on French clock movements. I'm sure someone will come along and give us the proper name for the "shoes" as you say. They do seem to be common the French round movements. I've always wondered about the value of the center one myself. :?| The one on the strike train is certainly helpful in synchronizing the strike side as it allows the pinion end of the star wheel shaft to be adjusted. :cool:

P.S. IMHO, since these movements have rather small barrels, the expansion size of the spring for your clock looks good to me providing it is a proper fill for the barrel.

Tom :cool:

[colour=blue]“Sometimes you really don’t know if your being rewarded or punished”[/colour]

 

shutterbug

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Hi Baz! I would not assume that your problem is spring related, even though it was quite dirty. It could be, but my guess is that it's another problem instead. As long as you have the clock disassembled, check other potential problems too.
 

dholk

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I have encountered a few pivot holes which were worn enough to require bushing (in my opinion), at least this corrected the intermittentent stopping. Also check to see that there are no bent teeth. This is rare, but possible.

I think you would call the "shoes" cocks, at least that's what I've seen them called in watches. I wish I could find a good glossary of clock terms.

Good luck,

David
 

dutch

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I would not change the mainspring but check the hole, I have had many starting to tear there.

Like Tom I have wondered about the reason for the center cock but the one on the strike side is really helpful.

Regards, Dutch
 

Chris

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The mainspring looks good to me. Check the end as suggested for breakage. Put the time train back in the movement and test the pivot ends for wear; normally, French round movements don't need rebushing, but the pivots may need polishing.

Check for bent teeth, too. I never really understood the "shoes" either; they cannot be adjusted as they have pins holding them in place. In any case, if they have not been touched in the past, don't touch them now! You can remove them to clean, but don't bend them side to side.

Have you rebuilt French round movements before? If not, there are tiny timing marks on the strike that must be aligned in order for it to count correctly and to ensure the lift pin does not touch the pins on the wheel prematurely. This can cause the strike side to fail to strike if they do touch.
 

Baz

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Chris said:
The mainspring looks good to me. Check the end as suggested for breakage. Put the time train back in the movement and test the pivot ends for wear; normally, French round movements don't need rebushing, but the pivots may need polishing.

Check for bent teeth, too. I never really understood the "shoes" either; they cannot be adjusted as they have pins holding them in place. In any case, if they have not been touched in the past, don't touch them now! You can remove them to clean, but don't bend them side to side.

Have you rebuilt French round movements before? If not, there are tiny timing marks on the strike that must be aligned in order for it to count correctly and to ensure the lift pin does not touch the pins on the wheel prematurely. This can cause the strike side to fail to strike if they do touch.
This is the first French movement that I had apart so I have taken many pictures to help in re-assembly.
I don't know about the timing marks - where do I find them ?
Cheers, Baz
 

Mike Phelan

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Baz

Springs look fine - if you put new ones on, they would not be as good or last as long.

The cocks to not need to be removed once you have cleaned them. Don't bother trying to adjust the striking with them.

There are timing marks on the strike train as follows:

Punch mark on pin wheel to meet chamfer on gathering pallet wheel pinion
Punch mark on GP wheel and chamfer on warning wheel pinion.
Set these before you put the plate back on.

Attach the gathering pallet so it is clear of the rack when the train is locked.
On the motion work:
Punch marks on hour wheel, cannon pinion and minute wheel.
Chamfer on minute pinion.

The last hundred of these I have seen have never needed any bushing except very occasionally for the barrel and barrel cover.

You will need plenty of metal polish, chalk and tissues! :thumb:

HTH
 

Baz

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Mike said:
Baz

Springs look fine - if you put new ones on, they would not be as good or last as long.

The cocks to not need to be removed once you have cleaned them. Don't bother trying to adjust the striking with them.

There are timing marks on the strike train as follows:

Punch mark on pin wheel to meet chamfer on gathering pallet wheel pinion
Punch mark on GP wheel and chamfer on warning wheel pinion.
Set these before you put the plate back on.

Attach the gathering pallet so it is clear of the rack when the train is locked.
On the motion work:
Punch marks on hour wheel, cannon pinion and minute wheel.
Chamfer on minute pinion.

The last hundred of these I have seen have never needed any bushing except very occasionally for the barrel and barrel cover.

You will need plenty of metal polish, chalk and tissues! :thumb:

HTH




Thanks for that Mike.
At first glance I don't see any of the timing marks you mention but I'll look again when the wheels are clean.
You are correct, there is little wear on the bushings.
BTQ what are the tissues for ?
Cheers, Baz
 

Mike Phelan

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Baz said:
Thanks for that Mike.
At first glance I don't see any of the timing marks you mention but I'll look again when the wheels are clean.
You are correct, there is little wear on the bushings.
BTQ what are the tissues for ?
Cheers, Baz
Hi Baz
Timing marks:
On the wheels, they are like a centre-punch mark near the gap between two teeth on the outside edge of the wheel.
To mate with this, one of the leaves of the pinion (on the end nearest the pivot) is ground away at about 30 degrees. Once you have cleaned it, they will be clearly visible.

One other thing you might have to do, if it has been disturbed, is to adjust the rack tail - it is just a tight fit on its collet. When the rack has dropped at 55 minutes or so, move the hands to the hour.
At that point, there should be a slight clearance between the top edge of the rack hook and the bottom edge of a rack tooth. Say 0.01".

For those who mainly work on American or modern clocks with thin plates and soft pivots, it sometimes is a revelation that pivot holes on other movements do not wear for a long while, and bushing is a rarity!

Tissues:
French clocks of this sort have all the brasswork finely polished; fingermarks can etch into the brass. You either need tissues or 'finger cots' once the parts have been cleaned.

Others will disagree with my methods, but a brief résumé of how I clean one of these is:
  • Do any repairs first.
  • If very dirty, use some sort of clock cleaning fluid (I use ammoniated Horolene) :eek: Yeah, I know!
  • Scrub all brasswork with Brasso and a stiff clock brush. Don't try to polish it.
  • Wash everything off in IPA or similar. Do not touch anything with fingers from now onwards. This will remove all traces of Brasso. Parts will be clean, but not polished.
  • Use a soft brush and chalk (search on forum for supplies - I use M & P in England) and polish everything - especially wheel teeth.
You will now have a movement with a brilliant deep polish that will retain it for quite a few years. I did a 1912 400-day here on my bookshelf about 25 years ago and it still gleams!

Of course, you could just dunk it in an ultrasonic; I think they deserve more when the maker has devoted time to polishing it like this - call it unnecessary work, pride of workmanship, whatever. :thumb:
 

Baz

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Mike said:
Baz said:
Hi Baz
Timing marks:
On the wheels, they are like a centre-punch mark near the gap between two teeth on the outside edge of the wheel.
To mate with this, one of the leaves of the pinion (on the end nearest the pivot) is ground away at about 30 degrees. Once you have cleaned it, they will be clearly visible.

One other thing you might have to do, if it has been disturbed, is to adjust the rack tail - it is just a tight fit on its collet. When the rack has dropped at 55 minutes or so, move the hands to the hour.
At that point, there should be a slight clearance between the top edge of the rack hook and the bottom edge of a rack tooth. Say 0.01".

For those who mainly work on American or modern clocks with thin plates and soft pivots, it sometimes is a revelation that pivot holes on other movements do not wear for a long while, and bushing is a rarity!

Tissues:
French clocks of this sort have all the brasswork finely polished; fingermarks can etch into the brass. You either need tissues or 'finger cots' once the parts have been cleaned.

Others will disagree with my methods, but a brief résumé of how I clean one of these is:
  • Do any repairs first.
  • If very dirty, use some sort of clock cleaning fluid (I use ammoniated Horolene) :eek: Yeah, I know!
  • Scrub all brasswork with Brasso and a stiff clock brush. Don't try to polish it.
  • Wash everything off in IPA or similar. Do not touch anything with fingers from now onwards. This will remove all traces of Brasso. Parts will be clean, but not polished.
  • Use a soft brush and chalk (search on forum for supplies - I use M & P in England) and polish everything - especially wheel teeth.
You will now have a movement with a brilliant deep polish that will retain it for quite a few years. I did a 1912 400-day here on my bookshelf about 25 years ago and it still gleams!

Of course, you could just dunk it in an ultrasonic; I think they deserve more when the maker has devoted time to polishing it like this - call it unnecessary work, pride of workmanship, whatever. :thumb:
Hi Mike
Thanks for that.
I have problems finding the timing marks, despite plenty of magnification in bright sunshine. I even used the square edge of a small steel rule to try and identify the leaf with a chamfer but with no success.
Trust me to end up with one with no marks.
Is there another way round this problem ?
When I was demobbed I had hoped that I would never use Brasso again. The smell of that stuff takes me back 50 years ..........
 

Mike Phelan

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Hi Mike
Thanks for that.
I have problems finding the timing marks, despite plenty of magnification in bright sunshine. I even used the square edge of a small steel rule to try and identify the leaf with a chamfer but with no success.
Trust me to end up with one with no marks.
Is there another way round this problem ?
Right - not seen one like this, but I suppose it had to happen!

There are two things to align that can be done carefully before you put the top plate on.

The hammer arbor lever needs to touch one of the pins on the hammer wheel while the pin on the GP wheel needs to be just above the rack hook detent.

At this point, the warning pin should be ideally half a turn away from the end of the warning lever. This latter is not too critical - providing the pin is not next to the lever and could stop the clock, too much warning run means less time for the train to accelerate before lifting the hammer.

When it is all together and running, gathering pallet needs to be nearly vertical when the train stops.

Finally, the motion work needs to be aligned so that when the cannon pinion with the outermost (hour) pin is next the warning lever, the 'big step' is just a few mm from the rack tail (this is 12 O'clock).

You may have to adjust the rack tail on its collet to get the clearance correct with the rack hook tooth engagement.

When I was demobbed I had hoped that I would never use Brasso again. The smell of that stuff takes me back 50 years ..........
I suppose any liquid metal polish would do, but I think they all smell the same! :eek:
 

Baz

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[quote time=1190355683 user=Mike Phelan uid=1128 fid=14 tid=
Right - not seen one like this, but I suppose it had to happen!

There are two things to align that can be done carefully before you put the top plate on.

The hammer arbor lever needs to touch one of the pins on the hammer wheel while the pin on the GP wheel needs to be just above the rack hook detent.

At this point, the warning pin should be ideally half a turn away from the end of the warning lever. This latter is not too critical - providing the pin is not next to the lever and could stop the clock, too much warning run means less time for the train to accelerate before lifting the hammer.

When it is all together and running, gathering pallet needs to be nearly vertical when the train stops.

Finally, the motion work needs to be aligned so that when the cannon pinion with the outermost (hour) pin is next the warning lever, the 'big step' is just a few mm from the rack tail (this is 12 O'clock).

You may have to adjust the rack tail on its collet to get the clearance correct with the rack hook tooth engagement./h

Mike
I found a quiet corner, studied your hints and figured it out.
It took 2 or 3 attempts but It's looking as though everything is in sync and working OK. I'll leave it running overnight without a pendulum and come back to it fresh tomorrow.
Strangely the front of the movement was much cleaner than the back and I didn't intend to pull it apart but I find that it strikes 9 at the 12 o' clock position. It also has literally no resistance when moving the minute hand and I assume the problem will be in the motion work somewhere.
Nice movement to work on and certainly different to the American/English/German clocks that I'm used to.
Thanks again, Baz
 

Mike Phelan

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Hi Baz
Well done!

Baz said:
Mike
I found a quiet corner, studied your hints and figured it out.
It took 2 or 3 attempts but It's looking as though everything is in sync and working OK. I'll leave it running overnight without a pendulum and come back to it fresh tomorrow.
Strangely the front of the movement was much cleaner than the back and I didn't intend to pull it apart
Oh? Thought you already had done!

but I find that it strikes 9 at the 12 o' clock position.
When the rack tail is nearly up to the step on the snail? In which case, it will strike 1 at 1, 2 and 3? The rack tail needs moving, then. Make sure it is not loose.

It also has literally no resistance when moving the minute hand and I assume the problem will be in the motion work somewhere.
Right. If you take the minute wheel cock off, and remove the motion work, look at the pipe on the cannon pinion; squeeze the pipe where it is cut out, but very gently indeed.

HTH
 

Baz

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Hi Mike
The strike problem was due to the snail cam being one tooth out and nipping the pipe on the motion work fixed up the loose minute hand.
It now seems to all OK so I'll let it run for a while before re-installing it.
Very many thanks for your help
Cheers, Baz
 

Times

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Another exciting question about French (round) movements mainsprings. I pulled out both mainsprings for visual inspection and cleaning. Both mainsprings appear to be identical: 0.30mm (or 0.28mm depending on how hard I try to measure them using a digital caliper), 19.25mm and about 1200mm in length. The barrels ID is 30.75mm. I see that mainsprings are being offered as 19mm and 20mm, but nothing in between. I also see that mainspring barrels are shown as 30.00mm, not 30.50 or 30.75, etc. Not a big deal, but interesting. One mainspring is broken at the outer end, and the second one is barely hanging in exact same spot - outer hole. Will try to re-hole them both.

I found some suitable replacement mainsprings 19x0.28x1250 x 30mm. Would someone recommend 0.30 instead of 0.28?
Also, I have noticed that both mainsprings have a 4-digit number marked at the very end. One appears to be 3391 and another could be 5352, or 5359 (hard to guess). Anyone could tell me what type of reference number that could be?

IMG_5481 - Copy.JPG
 

shutterbug

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It might be the pendulum length, using the French system. Two 2 digit numbers.
 

Times

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The pendulum length is stamped on the back plate: 4 8
 

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