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French Boulle Mantle clock - pendulum required "Click" to Login or Register 
posted
I have a French Boulle mantle clock that has lost its pendulum. The backplate bears a stamped "M" surrounded by "Marquee Deposee" and the numbers 5066 45. I found a picture of what appears to be an identical movement online and by scaling it, it appears the bob size would be about 1 1/4". Can anyone provide the correct specs (weight etc.) for the pendulum for my clock? Thanks in advance.

Clock movement
 
Posts: 3 | Location: Ontario in Canada | Registered: October 24, 2015
Life Member
posted
Size of bob is not nearly as critical as pendulum length. 4 5 indicates 4 pouce, 5 lignes. That should be the distance from the pivot point to the centroid (center of mass for pendulum, including suspension spring, pendulum rod, bob, and rating nut).

1 ligne = 1/12" = 2.255 mm, and 1 pouce = 1" = 25.4mm, so 4 5 indicates 114.5 mm, or 4.51 inches.

So a rod about 5" long would put the center of the bob at about 4 1/2 inches - close enough to get you within the range of adjustment for timing.

French pendulum assemblies come up from time to time on the well-known auction site, or there may be someone on here who has one lying around.

Typically for these round movements, the suspension spring is about 1.5 cm long, including the upper and lower blocks.
 
Posts: 213 | Location: Westminster, Maryland in the USA | Registered: March 02, 2015
posted
Thank you so much David - wonderful information. I should be able to get this little beauty up and running soon. (yes, suitable pendulums seem to be available online)
 
Posts: 3 | Location: Ontario in Canada | Registered: October 24, 2015
Life Member
posted
Forgot to mention - I am not positive, but I think the "M" logo is one that Marti Cie used for their clocks. I am not sure whether the other numbers are a serial number or a model number - I think they ae serial numbers, since I have never encountered any duplicates between any Marti clocks I have worked on.


If you decide you need to clean it, be careful when getting the mainsprings out of the barrels. French clocks are notorious for having thin mainsprings, and the end hole tends to tear out if it isn't treated carefully when winding and unwinding it out out of the barrel. If that happens, you can usually make a new end hole, by annealing an inch or so of the remaining spring, but it is a pain in the butt to have to do.
 
Posts: 213 | Location: Westminster, Maryland in the USA | Registered: March 02, 2015
posted
Thanks once more David. I have no experience in cleaning (let alone repairing) clocks. Fortunately, the clock is able to run (fast of course) and chime OK without it's pendulum, so I'll be more than satisfied just replacing the pendulum.
 
Posts: 3 | Location: Ontario in Canada | Registered: October 24, 2015
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