CUCKOO CLOCK REPAIR TIPS: (advanced)
The modern cuckoo clock is available in musical and non musical versions. The musical version has several variations. The music mechanism can be mounted on the side of the case (usually on the right looking in the back) or on the top inside just below the roof. All of these versions are available with count wheel mechanisms in one day or eight day versions. Most of these (with count wheels) that are musical have a worm gear drive governor with a large vertical fan mounted on the movement. be cautious of these , they tend to bind up often and won’t tolerate much wear. The music sounding part is mounted on the side usually and has only brass drum and the steel fingers there being no need for a governor assembly.
Commonly the roof mount mechanisms are 1 day units. There are 2 basic types of shutoffs: one that simply moves in and out of a hole in the side of the drive gear on the melody sounding drum, and another that has a graduated slot that the shutoff lever is moved out of and above a ridge on the drive gear so it holds the shutoff open until the valley comes back around and the shutoff lever drops in and the tab hooks the fan. On this type the secret is that the lock lever must snap out and up from the shutoff hole to keep it going. These are usually either 22 note or 18 note units.
All of the music mechanisms have small dampers cemented to the bottom of the fingers on the sounding bar. These dampers must come in contact with the small pins on the brass drum the instant before the pin comes in contact with small finger on the sounding bar as the music mechanism is in operation. The purpose of this is to prevent a squeaking sound from occurring as the pin contacts the finger while it is still vibrating from the last stroke. If these dampers are missing or defective they must be replaced or the music mechanism will squeak. That is it. There is no other way, Do not attempt to oil the sounding fingers ; this will not stop the squeak without causing the sound to deaden, and will eventually thoroughly gum up the mechanism and ruin it.
HUBERT HERR CUCKOOS:
These mechanisms have a shutoff system that depends entirely on gravity to operate. Do not oil this system or it will not work.Looking at the mechanism from the front: the shutoff lever reaches across the outside and drops down on the rod with the little brass weight that looks like a bushing and pops it out of the way of the locking lever on the inside of the plate. The angles here are critical. Do not change them. Be sure the position of the 3rd wheel does not change ; if it is rebushed the lock will not set and hold if this wheel position changes.Oiling this causes the thing to hang up fr9om the surface tension of the oil. If it is hanging up , polish it carefully but do not oil the hook or the rod. some of the older cuckoos do not have an inspection hole in the back to allow access to the gong and hammer for adjustment. There are several ways around this. The least desirable is to drill a hole near the center of the gong. The reason I say least desirable is this : you may very well end up with a very angry customer when they see the hole you drilled in their prized 100 year old family heirloom that great grampa brought from germany during world war 1. Do not ever alter someone’s clock unless you have a very good understanding with them; and even then you are taking a big chance. The best way is to adjust the hammer/gong clearance before the bellows are installed. The hammer and gong can be seen through the hole for the bellow. It is possible to reach the hammer with an adjustment tool. Bend the hammer not the gong. I am remembering here the time I was adjusting a cuckoo for a customer at the counter ; and just a slight adjustment on the gong and ……….. OH NO!!!!!!!! Guess what happened ? the gong broke off in my hand. Unbeknownst to me and the customer the last person to work on the clock had taken the fatal short cut and bent the gong several times just enough. Hubert herr roof mount music mechanism : trip lever has to be absolutely free to move or the clock will not cuckoo because there is no return spring. Just enough to weaken it and now it was my turn to break it. Bend the hammer , not the gong. The 1 day regula cuckoo clock movements with 77mm x 75mm plates (stamped with 35) have common pendulum lengths of 28.5 cm and 20.5cm. The smaller regula movement 73mm x 63mm usually is available in 23.5cm pendulum length. These are the same chain size. 61links per foot and a wire diameter of .035in.. The pendulum length is measured from the suspension post to the center of the pendulum, bob or leaf.
SESSIONS 2 SPRING W/C: Set the hour trip position on the front cam and coordinate with cam on the back of the centerpost: cam on back of centerpost should move the pin on the hammer lift assembly into sequence hole before the quarter hour trip and them drop off edge n the half hour . Be sure the idler gear on the front plate is tight. The cam on the back
of the centerpost must be tight . Set the hammer sequence at the ¼ after position.