Clock Repair Archive – –
The sonora chime by Seth Thomas that has dual chimes (whittington
and westminster ) has 2 small dials about 1 inch in diameter on the top of the
face. One of them is for the chime selection and the other is for the timekeeping
adjustment. The mainspring in the chime unit is larger than in the single chime
unit; it’s dimensions are: strength: .0215inches thick by 1.375 inches wide by
approximately 106 inches long.Be careful with this spring. When it is wound fully it
has a lot of energy stored in it. If you are installing this with a spring winder, I
would strongly recommend wearing a face shield; not just eye protection, but a face
shield and eye protection. The sequence of the hammers is as follows: looking in the
back of the case assign numbers to the hammers and let the hammer closest to the back be #1 .
The wittington sequence is as follows at the quarter hour chime: 1, 4, 6, 7, 2 ,3 ,5 ,8.
The westminster chime at the quarter hour is: 6, 7 ,2 ,8.
This clock has two mechanisms. The one closest to the front of the clock powers
the strike and the time gear trains. It also trips the chime. The chime mechanism is
closest to the back of the clock. The chime mechanism has a huge mainspring and mainspring
barrell. Pay very close attention to the teeth on this barrell; if this mainspring or
barrell lets go , it will do much damage to the mechanism and possibly to someone’s finger.
Most of these clocks are not self correcting on the chime or the strike.The
mechanism that runs the strike and the time is very similar to the 8 day
time and strike american clock mechanisms. The chime usually is sounded on a row of bells
mounted above a resonating box. These clocks have a beautiful sound in my opinion. The hammer
sequence is different on these clocks than on the modern german w/c self correcting
mechanisms.
The time and strike mechanism is activated by the chime mechanism,
however, the chime mechanism is activated by the trip lever and the trip cam in the
time and strike mechanism. It is a good idea to be very sure you have the lift wires
correctly adjusted before you re-install the mechanisms in the case. I have usually
set them up on a couple of blocks outside of the case to get the adjustment reasonably
close before installing the mechanisms.
Be absolutely sure to check the ratchet dog system on
the chime mechanism; I have seen many of these loose when they come in for repair.
If one of these lets go, the results will be disastrous indeed. The mainspring in one
of these mechanisms is powerful enough to easily break someone’s finger. There is usually
a pin on the inside of the ratchet that the click spring pushes on to make the click
work. Be sure to check this pin very carefully, it must not be loose or the
ratchet system will fail.
The pendulum on these mechanisms usually will have at lease 2 inches of
swing, and the pendulum bob is one of the heavier (2+ ounces typically) types.
Before getting too far on the repair of one of these clocks . it is very wise to check
the gear teeth on the chime mainspring barrell. If the barrell is bad , there is no point
in doing the rest of the work until the barrell problem can be resolved. If the chime
mechanism won’t work, then neither will the strike . The hammer throw is critical
on these clocks ; it may have to be reduced if it has been tampered with. Take the
hammer assembly out, take it apart and clean it throughly. If you do not do this
you will be insulting the integrity of the owner and the quality of the clock.
I have frequently seen these mechanisms bind up because of excessive hammer friction
due to too much throw or gummy oil.
Unless you are working on a family heirloom, be prepared to have trouble with
these clocks. Not that they are bad; on the contrary, they are excellent clocks in my opinion.
Many of them I have seen have been butchered, or have had so much oil slopped on the gears that
the chime mainspring barrell has teeth that are dangerously worn. You can save yourself a lot
of headache and embarrassment by checking the chime mainspring barrell while the customer is
there, if possible. If you have too many customers to check it at the counter, be sure to
check it BEFORE you get into the repair. Look at the teeth on this barrell carefully. If you see
grooves worn in the teeth be alerted. It has been my experience that more than 10% wear on
these teeth will cause the chime to bind up sometimes. I have seen them with more wear that
will still make the chime work. This is an extremely dangerous situation. Here we have a situation
of what you can get by with, and what is a good restoration. The damage has already been done.
Now the owner has to decide if they want to keep the original barrell and risk destroying the rest
of the clock by running it until the thing explodes, or not running it and having it original.
It is a judgement call as far as the antique condition of the clock is concerned.
The hammer sequence on the single melody westminister chime is different than usual.
It is as follows: looking in the back of the clock and assigning numbers to the four bells
used for the quarter hour melody starting with the bell closest to the back door
and calling it #1 and the one next to it #2 ,Then #3 and finally #4 , not counting the
bell used for the hour strike or course , the order for the quarter hour chime (down
the scale westminster) is ; 2 ,4 ,1 ,3 . This same sequence would also apply to the
3rd measure of the 3/4 hour chime.