Re-assemble a Hermel clock chiming train

[rkw]

Hello Bob and fellow repairers.
I am going to strip and service a Hermel eight day Westminster clock movement 340-020. Before I disassemble the movement, as a reference I fully photograph the movements workings.
My question.
I know that French clocks have cogs are marked and these marked cogs must be re-aligned when the movement is re-assembled.
On my Hermel clock movement there are no visible alignment markings. How do I re-assemble the chiming train so that the chiming sequence is correct, do I set the clock to an hour and mark/scribe the chiming train and hammer cam, taking note of the warning pins position before I disassemble the movement. Alternatively Can the chiming sequence be adjusted once the movement is re-assembled? Following your tutorial I keep the movement trains and mainsprings separate, to ensure the correct gears and spring are re-installed in the correct train.
Thank you for an excellent web site. Roger

[Bob Tascione]

Hi Roger,
I don’t know if there’s really a way to pre-mark things so everything is in sycn after re-assembly.I do have a quick way to set everything up that seems to work for me though. First thing though…try to study the set-up to understand exactly how and why it works. This is an important step to take with anything that may not be familiar. There are so many different designs for clocks and watches (that’s what makes it so much fun) so it’s always a very good idea to study anything that’s new to you. Taking pictures is an excellent idea ….. as is making any notes and drawings you can think of. After doing a certain type of set-up a few times it becomes much easier but the first time can be a real bear if you have little or no understanding of how it functions. It’s like someone handing you a box of unfamiliar parts and telling you to put IT together. If you don’t know what IT is you’ve got a challenge ahead of you.

Yes the chiming sequence can be set up after the movement is assembled on the Hermle 340-020 which is really, really nice. I’ll get to that in a bit but first…setting up the locking pins etc. WARNING!!. My terminology might be off here so if I’m calling something by the wrong name please forgive me as I don’t have a book down here with me with the proper names and I’m notorius for forgetting proper names. Please correct me if I screw up a name.

First Let down all power!
Next loosen the screws that hold the Chiming Lock Wheel and Count Cam (see attached pics) so that they are free to rotate on their arbors. Turn the warn wheel so that the warn pin (no pic) has a 180 degree run to the warn lever. Should be at about the top…12:00 to 1:00. Hold in this position and turn the Count Cam so that the Cam Lever Pin drops in the SECOND slot after the largest cam lobe NOT the first slot and then turn the cam a little bit more if necessary so that the lever is resting just before the next lobe is ready to lift it. You may need to move this one way or the other later if things don’t lock quite right. Tighten the Count Cam screw. While holding everything in this position rotate the Chiming Lock Wheel until it’s locked in place by the Chiming Lock Lever then tighten it down. If you use the first slot on the Count Cam instead of the second slot it will still work but makes it tougher to get everything in sync. Being in the second slot allows for adjusting the chimes for the quarter hour…which has the fewest notes and for me is easiest to decern.
Now you can adjust the chiming sequence by loosening the screw on the top wheel on the back plate. Begin turning the chime wheel by turning the lower wheel on the back plate until you get to the quarter hour chime…that’s the one that has 4 descending notes. JUST after the hammer falls off final pin allowing the last note to sound tighten the top wheel in place. You may need to mess around with this adjustment a little but once you get the hang of it it’s pretty easy. It’s very important that the chime doesn’t stop while lifting a hammer as this can stop the train. It must stop right after the last pin clears the hammer and well BEFORE lifting the next hammer. If it’s advanced too far forward then the train will begin lifting the hammer during warn and not have enough power to start again. It needs to have a bit of a run at the hammer when the chiming process begins.
Hope this helps Roger,
Enjoy!
Bob

• This reply was modified 2 years ago by Tamas Richard.

[rkw]

Hello Bob and thank you for the very detailed response, over the week end I will follow your advice and let you know how I fair.
A word of warning to all new disciples of clock repair. When removing a main spring and you chose not to wear gloves and protective eye glasses, that spring packs a painful punch and I have the bruises on my fingers to prove it. It was a good lesson respect the power in a spring.

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