Clock repair blog

FAN (governor) BALANCE:

Clocks that have governor fans must have them balanced. Either replace
the blade or adjust the balance by bending SLIGHTLY the wings of the fan. Also
filing some of the edge off on the heavy side will work, In severe cases, it may be
necessary to cut some of the brass off. Some fans are adjustable mainly to vary
the speed of the gear grain; however this adjustability can apply to balancing
also. Set the desired speed and then with small adjustments set the balance.
GOVERNORS MUST BE BALANCED OR THEY WILL NOT WORK dependably all the
time. Just rebushing and polishing the pivots will not fix them.
I cannot stress this enough. Here is the typical senerio. You repair a grandfather
clock. The governor bushings are just fine and the pivots are ok. The main wheel bushings
are bad on the strike and the time and the depthing of the gear teeth there is way off causing power loss. Enough to actually stop the clock. You see this and know it because you have seen it thousands of  times before so you are sure. You spend 6 hours working
on the mechanism and finally get it back together and in the case for the test run. You test
the clock and everything is fine. You take the clock back to the customer and all goes well;
or so you think. A few weeks later you get a call from the customer and they complain “the chimes don’t sound right”. You say ok , its just run down and gotten out of sequence. You do a service call and when you get there everything is fine. So you check the unit out and they customer is happy , and you think all is well … you hope all is well.
Three days later you get another call from the customer. Now they are quite upset and have the same complaint. Now if you did not know about the fact that governors MUST BE
BALANCED you would loose a customer and , drive yourself nuts trying to figure out why the thing keeps getting out of sequence. I discovered the answer to this about 5 years into my  career. In clocks you have only a very very small amount of power available to turn the governor or the escape wheel. If the “heavy” side is down when the governor stops ; there sometimes will not be enough power to get that heavy side to overcome the pull of gravity and the strike ( or chime ) will stall once. But not every time. Now why ? Well since we are not living in a perfect world there are always going to be some inconsistancies in gear trains and gear teeth. When the gears get to the point when there is , lets say , a thousandth of an inch difference in the spacing of the gear teeth on one of the gears , because you loose power exponentially as you go up the gear train, the power lost by this difference is just enough to prevent that governor from starting with that heavy side down. There could be any number of factors that combine at different times to be just enough to prevent that governor from starting. Now you may say that this is crazy. All I can say is that if you do clock repair long enough you will find out that this is true and you will always check the balance on governors before you put the clock back together. And you will have less headaches and more happy customers. This is mainly true in grandfather clock governors as they are sometimes quite large and  heavy. Spring drive clocks are susceptable because when the mainspring runs down slightly the power decreases and balance becomes more critical. On smaller governors the likelyhood of balance problems decreases somewhat ; but I would still recommend checking them. If you don’t on the first repair and they come back , if you are smart you will check the balance. I have repaired at least 17,000 clocks in my career and have seen problems  with far more than that in training other repair technicians and I can tell you for sure if you are not aware of this problem with governor balance there will be clocks that you will not be able to figure out. If you are in business , you may be seeing a lot of some of your customers that you want to. The downside of being aware of fan balance is that you might not get as well acquainted with some of your customers!

Governors that work by spinning weights or by friction are not as touchy about
balance but they are not as dependable as air operated governors. They are also not as
common; in my opinion, they are not a good design for use in clocks.
Most fans ( governors ) also have a clutch that allows them to slip on the shaft .
It must be tight but not too tight. If the clutch is too loose, the fan will slip and the
gear train will move too fast , usually WAY too fast.
If the clutch is too tight , the fan will not slip at all and not enough
of the shock of the shutoff action will be absorbed and the gear train will bounce
back when it stops. The shutoff cam and shutoff cam pin and any other parts of the
shutoff mechanism that absorb the shock of the gear train shutting off will be damaged
by the added stress that is supposed to be absorbed by the fan clutch. If the gear train
recoils like this when it shuts off sometimes it will bounce back far enough to jam the
lock pin in the shutoff lever.

SCORED PIVOTS:
Actually any kind of inconsistency on a pivot will cause a problem. Keep in
mind that a clock mechanism operates like a crowbar in reverse. Try operating a
crowbar backwards like this; apply force on the short end of the lever to a load that
you can just barely move. Now add a small weight to the load side and see for
yourself how much effect it has. This power relationship is similar to the power
transfer that occurs in clock mechanisms.
A pivot that is not perfectly round will impede power transfer. A pivot
that is not straight will cause problems : exceptions french clocks and some veinna
regulators. A pivot that in any way impedes end shake will stop a gear train. Always
check endshake under no power and under partial power. A pivot that is bent , even  slightly, will cause stoppage. A pivot that is off center with respect to the gears on
its shaft will cause problems. (power loss) . A pivot that is scored will cause problems
(accelerated wear and reduction of available power) . A pivot that is pitted or gouged
will cause problems( Accelerated wear and power loss) . Any foreign material in the
bushing that comes in contact with the pivot will cause problems (power loss and
possible wear problems). A pivot that is not long enough to have at least some (.010in.)
of its working surface outside the plate will cause problems(lack of endshake or improper
wear). Any rust or corrosion on a pivot is catastrophic; if the clock does run ,
it will be only a matter of months before the pivot and bushing are totally destroyed.

SYMPATHETIC VIBRATION:

This is a phenomena that sounds unbelievable at best, but it does exist and
is a common cause of many clocks stopping. Sympathetic vibration is the transfer of
energy from one object moving with a steady frequency to another object (initially
not moving( connected to it. The objects will transfer energy very
efficently if they are the same length , however , they do not have to
be the same length to transfer energy . A classic example is a large
grandfather clock with a heavy pendulum and a case that
is set up on a rug.When the weights travel downward and get even with the pendulum
bob ,the weights will absorb enough energy from the pendulum to either stop the clock
and or start the weights swinging and stop the clock. Also the clock case can absorb
energy from the pendulum because the case is not solid on the rug. Even the s
lightest instability can cause the clock to stop. On old cases ; if they are loose, if the  case is not solid, the pend moving will cause the case to oscillate (this may or may
not be visible) and the case will absorb enough energy to stop the clock. correct
is by securing the case to the wall. be sure the case is solid.

If there are several clocks running on a shelf with similar pendulum
lengths , and the shelf appears solid it still may be possible that the clocks on
this shelf will transfer energy back and forth. The result may not be just stoppage.
One or both of the clocks may not keep time or may be un-regulatable because they
will affect each other.

Sympathetic vibration may be demonstrated by a little device with weights
and strings. Start one weight swinging and very soon the other one will be swinging,
and the first one will be stopped.

CLOCKS WITH STEEL PLATES:

There have been a number of clocks made that have steel plates instead of
brass. Some of them have brass bushings installed and some of them don’t. If you
are using special reamers ; do not try to use them to ream out the steel,they will be  destroyed by the hard steel : it will dull them immediately. The brass bushings that
are factory installed will push out if you don’t have something backing it up when
he new bushing is pressed into the larger factory bushing. Some plates are brass plated
steel. Be sure to check the plates with a magnet before reaming.

CALENDAR CLOCKS:

A very important word about calendar clocks. DO NOT EVER OIL
THE CALENDAR MECHANISM;EVER. YOU WILL RUIN THE MECHANISM
IF YOU DO. They work on gravity power and they do not need oil! This applies to double dial types old and new. The types that have the calendar on the main dial
are a different story. They can be oiled but don’t need oil particularly; however if
there is a separate mechanism, be careful, if it works with a lever and depends
on gravity to work don’t oil it.

TOOTH STRAIGHTENING:

Bent teeth can be straightened if they haven’t been bent so far so as to
crack when they are driven back k into position. Check with a magnifier at the base
of the teeth that have damaged . If there is no visible start of a fracture line
then they will probably straighten without breaking. One or two teeth can be
straightened without much consequence on most spring barrels. The bigger the barrel
the more risk involved . #2 and #3 wheels are less critical, obviously because
less power is involved.
After the tooth is straightened , be sure to smooth the rough edges , taking
care to keep the original tooth shape as much as possible. Reinstall the gear in the
mechanism with the gear on the top and the gear on the bottom and carefully check
to determine if the gear train operates smoothly. This is a last resort fix: sometimes
it works; and sometimes it doesn’t . If a gear can’t be cut ans a replacement can’t
be found then the teeth must be straightened or replaced if the mechanism is to work.

GEARS:

The gears found in most clocks differ in several ways from other gears.
Usually the main wheel , 2nd wheel , and third wheels are part of a slow moving gear
train in time and strike and chime gear trains. The time train , particularly , is slow
moving all the way through the gear train. These gear trains work in an opposite
fashion from the gears; say; in an automobile. In a clock there are gears driving pinions
in a slow moving situation. In other situations there are pinions driving gears in a
speed reduction situation and gaining power as the energy is transferred through the
gears. In a clock , power is lost as the energy is transferred, Because of this , the tooth
design is cycloidal instead of involute. The gears are almost always brass and the
pinions steel because the brass is softer than the steel and will not wear out the
smaller pinions because there are many more teeth on the gear. In practice what
actually happens is exactly what should by design the pinion teeth and the brass
teeth both wear at the same rate if oil is kept out of the gear teeth. If , however , the
gear teeth are oiled they will destroy them selves , Looking at the illustrations you
will see that the involute tooth is stronger, but the cycloid is smoother and offers
less resistance to movement.

URGOS 9 TUBE CABLE DRIVE FLOOR CLOCK

This mechanism is nothing like the Herschede 9 tube clock. Except for the
differential like gear system on the chime side the rest of the mechanism is like the
standard rod chime cable drive urgos mechanism. The beveled gear system that drives
the chime must not be tight and the drive shaft that passes through the center of the
hammer lift drum must have the gear on its end PERFECTLY centered in the idler/drive
gears that mesh with the power train and the sequenceing train . Do not forget the
washers that belong on the end of the shafts in the transmission assembly, they are
critical to the centering of the drive gear assembly. Set the chime lock / trip pin on
the warning wheel at the 3 o’clock position EXACTLY , otherwise there will not be
enough governor spin before the first hammer picks up. Be absolutely certain that the
lock position is set accurately , because to change it after the mechanism is together
will mean much wasted time in much dis-assembly because the wheel is buried in the chime hammer assembly and is not readily accessible. Install the tubes
with the weights OFF otherwise they may easily be scratched. Another common
problem is the mechanism jamming up because the dial causes the plates of the
movement to twist slightly when the mount bolts are tightened.Be sure to check for
plenty of slack in the mounting procedure so as to not cause mysterious sudden stoppages.

Regulation:
popular European mechanism balance wheel new style : with large hairspring and
threaded timekeeping adjustment: the small style found on the 130-070 regulates
faster by turning the adjustment screw clockwise. The larger balance wheel
(found on the 050 mechanism) regulates opposite: that is it will run faster by
turning the adjustment screw counterclockwise.

HAMBURG -AMERICAN CLOCK COMPANY

Re: the beehive style case named the celebrate . This model has 2
jewels in the escape wheel. The hammer sequence is as follows: 3, 4 , 2 , 1. for the
westminster on the quarter hour. The longest rod being referred to as #1, and this rod
being the closest to the back plate of the mechanism. As for the regulation : 1 turn is about 1 minute per day . Turn the regulator to
the right to make the clock run faster and of course to the left to make the clock run
slower. The movement number on this clock is 865. The manufacturer is
Hamburg-Amerikansche Uhrenfabrick.