Clock Repair Archive – –
TIMEKEEPING
The Herschede with the imitation mercury pendulum has a weight inside the center of the
imitation vial. It is hidden so be aware of this and check it out if there is an unexplained
regulation problem. This weight can slide up and down inside and disrupt the center of gravity
on the pendulum. If the clock runs fast and can’t be slowed down the weight is probably stuck
in the up position inside the cylinder.
Check the impluse pin on the pendulum. If it is loose you must tighten it. If it is slightly
loose you must tighten it. If you can see it move it moves too much. Tighten it. If it is pitted or
worn you must tighten it.
If the pendulum wobbles it may mean the suspension spring is bent. They can be straightened, but
it is very time consuming. It is best to replace them. Sometimes the pendulum will wobble if the
suspension spring is jammed in its holder and is not free to slide. Check that before you replace the
spring. This is true of all clocks with a suspension spring. This will also influence the timekeeping.
Suspension springs do not just bend themselves. The most common ways they get bent is during regulation,
or removal and re-installation. Use the utmost care when adjusting the pendulum position with the adusting
nut. If you twist the pendulum slightly the suspension spring can be bent and you may not even realize it.
ADJUSTMENT AND REPAIR
Most of the Herschede 9 Tube and 5 Tube grandfather clock mechanisms
are very will built. The majority of the problems on these clocks are created by well
meaning uniformed repair persons. The two racks and snails are the areas to look
first for problems. When the rack hook is lifted on either side (chime or
strike) ; the rack should move neither up or down; it should simply stay put as
hough nothing were happening until the hook releases it. If the angle is disturbed
on either the rack or the rack hook, then there will be a problem to the extent as to
how much the rack moves when the hook is moved up or down slowly. Be sure to
check the hub on both sides of both racks ; the angle is critical and they must be
absolutely tight. These rack problems most likely start with wear on the gathering
pallet arbor bushing. Take the time to check the operation of the gathering pallets
EXTENSIVELY before final assembly; particularly if you have had to rebush them.
The angle here is critical; I cannot stress this enough. Most of the problems
with Herschedes are here. If you do not FULLY understand how these work, do not even
attempt a repair on a Herschede clock until you do. If you dive into one of these
without checking this out first you will be very, very sorry. Be sure to check the tightness
of the gathering pallets on their square shafts before you reassemble the mechanism.
They must be very tight on the shaft or they will work themselves loose over time.
If they are not tight , make them tight or replace them if necessary . A SMALL
amount of silver solder on the square shaft will tighten them up. remove ALL THE
SOLDERING FLUX WHEN YOU ARE DONE. Do not use soft solder it will not
hold it shape well enough.
Be sure to mark the centerpost hour tube assembly so it goes back together exactly
the same way it came apart. (Some times the hour tube support is not symmetrical
and the center post will bind.) Put the same screw in the same hole and the same corner
in the same place.
Pivot polishing is critical on this mechanism especially. Many of these
mechanisms have a plating on most all the pivots. Be sure to completely disassemble
the main wheels and polish the area where they ride on the arbor behind the cupped
tension washer. If this area is not polished , the winding process will soon cause it it
bind up. Plenty of lubrication is needed here. I have heard some say why polish in
that area, you are just causing that problem; everything is fine until the plating is
removed. That is all well and good if the plating in fact has not broken down. My
opinion is this : do the repair job once so that it will work , or do the job once so that it
might work , and then do it again so that it will work. A Herschede overhaul is a major job.
If you mess it up, you will have an enormous amount of work. If you are smart you will heed these
warnings. I have already been through this.
The moon dial on this clock will stop it if the detent spring is too tight. Be
sure to check the spring to confirm that it is just tight enough to allow the dial to
ratchet ahead and hold but no tighter.
Always check the impulse post on the pendulum. It must be tight. If it is
loose at all the clock will not run., Be sure that there are no rough spots on the post
or the impulse arm where the post rides on it.
Be aware that if the hammer lift drum is submerged in the cleaning liquid, it
es very likely that a substantial amount or the cleaner will get inside the drum and
later leak and run all over the drum and its adjacent parts. Either clean this outside
of the liquid by some other method or drill (carefully) holes in the ends of the drum
so the liquid can drain out immediately. The winding key on the 9 tube clocks is a
number 13 or 14 depending on how much wear there is on the arbor.
Very carefully check the cords that the bells hang by and the hammer
lift strings to be sure they aren’t decayed. Also check the hammer pads and change
them if they have worn through.
The drive gear system that turns the hammer lift drum needs to have some
play in the gear depthing, it must not be tight. About 30% of the way to the gear teeth
not meshing at all will allow it to work. The beveled gears are particularly critical.
Be sure to tell the customer to not change the chime melody while the clock
is chiming or even when the clock has gone into the lock position ( 5 minutes to the quarter hour ).
The pulleys must be taken apart, cleaned and checked. Do not simply throw them into the
ultrasonic cleaner and call it good. You will be sorry if you do. The shafts that the
pulleys ride on are pitted or scored in about 90% of the clocks that come in for a
complete overhaul. The shafts must be polished thoroughly and the pulleys rebushed
if they are loose or worn. If you do not fix this problem with the pullys the clock will not work
correctly. You will need to chuck the pulley up on a lathe and center the hole for the
bushing. Don’t just drill the hole out and press in a bushing. That won’t work. You will not be able to
center the hole. It must be done on a lathe. I have seen pulleys bushed this way. The reason I have seen
them is because the clock did not work after the repair was done and the repair person could not figure
out what was wrong. I know this because I have made the mistake myself, and I have seen others mistakes.
Always check the cables; specifically the ends that are inside the main
wheel drums. If only the ends are bad, then simply retie the knot in the end . This
is a corner you can cut safely IF THE REST OF THE CABLE IS OK. If any breaks
or worn spots are found on the brass cable REPLACE IT. Check inside the drum where the
cable is held. If there is a sharp edge inside there, smoothe it out and replace the cable.
If you don’t do this the cable will keep breaking. If the chime weight cable breaks when the
weight is all the way up, the weight will go through the bottom of the clock case and smash
whatever is below it. The chime, strike, and time weights are marked on the bottom.
The Hershede was designed to run with brass cables. DO NOT PUT STEEL CABLES ON THIS CLOCK. These
are high quality clocks designed to be kept in families for years and years. Sure steel cables will
work for a while. But there is a good possibility that after you are dead and gone those steel cables
will ruin the brass pullys that are on the clock and at that time it may not be possible to fix. You are
not helping anyone by doing this. If you own a Herschede be sure the repair person does not use steel
cables on your clock. I have repaired many of these and there is not a need for steel cables.
They work fine with brass cable. I have seen many other grandfather clocks with brass cable 50 years
old still in perfect shape.
The strike and chime fans ( governors ) ABSOLUTLEY MUST BE BALANCED. Most of them are adjustable
mainly to set the speed of the chime and strike. If they are not balanced, however, they will stall
sometimes and create all sorts of other problems. So how do you balance one of these?
Do this: ( on smaller Herschedes )
Put the plates together. Set the governor on top of the plate as if it were in the plate, so it can
roll freely. Give it a very slight push to get it rotating slowly and watch it. You will be able to
tell if it is heavy on one side by watching it. If it stops in the same place every time you push it,
then the blade that is down is too heavy. Move it in. If you see it move, it might have moved too much.
Keep doing this until it stops only in random positions. If you do not balance the governors on this clock
you will be sorry.
On larger 5 and 9 tube Herschedes that have brackets for the fans, you will have to put them in
the bracket. Do not do this with the other gears in the gear train, or the friction of those gears will
destroy your balanceing efforts.
Sound of of the chime
On the tubular clocks the sound is softened by the presence of leather pads in the hammer
heads. The thickness of this leather will determine the amount of higher frequency sound in the notes.
Of course there is a limit to the thickness because the hammer heads must fit together, and it is not
possible to get the pads in there if the leather is too thick. Now measuring leather with a micrometer
is not a very accurate operation because as you squeeze on the leather you will reduce the reading on
the dial of the instrument, so there is a huge margin of error here. Much over .040 inches of thickness
will be difficult to install. This would be a guideline for thickness. There have been different styles
of hammer heads made for these mechanisms, so your experience might be slightly different. On most of
them I have done, the hammer heads come apart and the leather goes inside with just enough room to put
them back together and hold the leather in place. I am not a fan of leather of any kind, but that is just
a personal thing. The original was leather. This is why I mention it. My experience has been that the most
important thing is that the customer is happy with the sound.
Many times these clocks come from homes where they have been running for maybe 20 years
or so with no change in the hammer pads until one of them wears through to the metal below, then the
owner will definately notice the abrupt change in sound characteristics, even if they are tone deaf,
and call for service. Now what they don’t know, and you should know before you change all the hammer pads
is that the sound has changed in all those years, and because it was so gradual, sort of like a tree growing,
the customer does not realize it. What happens is that the leather hardens up from repeated striking and age.
This gradually makes the sound sharper. Then the well meaning repair person comes along, hears this, and,
knowing that a Herschede should not sound like a dinner bell, replaces all the leathers in the hammer heads
and proudly brings the clock back to the customer. When the customer hears it, they just go off like
a screaming banshee. They are absolutely furious that you changed the hammers on their heirloom and they want
you to change it back. Well, now you are really stuck because there is no way you can return that original
sound they were used to. Trying to explain this to them will just make matters exponentially worse, as you may
well imagine. you’d better have good insurance, because you are probably going to need it. What is the moral
here? Change only the hammer that is bad, and try to get it to sound like the others. Take the clock back,
and explain this situation to the customer, AFTER they have heard it, and are satisfied with what you have
done about the sound, and the leather, and such. Keep in mind that to most people, the sound of their clock
is the thing that is the most important to them whether they realize it or not. If it changes, they will
usually notice it. If you change it, then it’s your fault, or you get the glory, depending on how you
communicate your work to them.
