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Function Sessions Tall Case

Johnny Lee

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Sep 20, 2021
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I've taken in a Sessions chain-driven, tall case with a broken stick pendulum. The longer portion of the stick is missing. Can anyone help me with the length?

The mechanism, apart from being dirty and dry, appears to be sound. I'd like to solve the pendulum issue and test before doing disassembly.

I removed the bonnet with mechanism to bring to the shop. I don't have pix of body of the cabinet.

Thanks.
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Willie X

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Feb 9, 2008
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Just make the pendulum stick long and tape the bob in place. Move it up or down as necessary.

There are often arc shaped marks left by the old pendulum's rating nut. Going by these ghost marks will get to close at the start. Just don't cut the stick until you have it keeping time. Even at this point it best to make the cut about 1" longer than you think necessary.

Note, cutting off the excess stick will speed up the clock a bit, so leaving an extra inch is good insurance that you will have enough stick to get it back to rate. You have to sneak up on it. Failure to do so will result in you getting extra practice making pendulum sticks. :)

Willie X
 

Andy Dervan

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Oct 23, 2002
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Most grandfather clock pendulums are roughly 1 meter (39") in length. Willie provided good guidance.

You could check with horological parts suppliers: Merritts, Timesavers, and Griffen's Clock parts. They probably sell complete wood pendulum rod and bob kits.

Andy Dervan
 

Jim Hartog

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Jan 6, 2010
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Hello Johnny,

I have a Sessions weight driven, chain drive movement in a mission floor clock and the chain does not look like yours. Does that chain actually work? Mine is jack chain, not ladder chain, but yours is what some call "plumbing" chain since it was used on early toilets. The Monitor Clock Co. used this kind of chain.

Don't expect a seconds pendulum. My clock is either a 68 or 72 beat clock. The pendulum (missing, so I made one with a 4.5" Sessions bob) looked too short for the case so I played with "lengthening" the pendulum by making the rod heavy (steel) and the bob light (wood) to "stretch" it. The center of oscillation was not changed by my shinanigans, but I was able to get a significant length change with no function change by redistributing the mass from the bob to the rod. Do you have the standard Sessions 4.5" bob? It will have S Clock Co. embossed in the iron back.

The other thing I did was to make a pendulum leader with the top hook and slot in a short rod, a couple of inches longer than the piece you have. Then the rest of the pendulum is made to hang from that. Make the leader long enough so that the pendulum can be hung onto the leader easily.

I am also wondering why I don't see a seat board in your photos. The weights are likely heavy.

Page 257 of Tran Duy Ly's Sessions Clocks book shows my movement (No. 31) with the jack chain, 2 piece pendulum and round top weights. My weights were also missing so I copied the profile from this picture. The caption implies that Sessions sold the mechanicals separately. There are only two floor clocks by Sessions in Tran's book, both electric, so assume that your case is not Sessions.

Jim
 

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