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Care and Maintenance of Antique Disk Music Boxes
Care and Maintenance of Antique Disk Music Boxes
If you’re reading this How-to Guide, you probably already know that the majority of music boxes have their tunes “encoded” onto a cylinder, or alternatively into interchangeable flexible metal disks; and you also know that, in both cases, notes are played each time a pin or similar protrusion “plucks” a tooth in the music box’s comb as the cylinder or disk rotates.
But this is where the similarity between most cylinder and disk music boxes ends. Because, while the plucking action of the pins in cylinder boxes acts directly on the comb’s teeth, most disk boxes are equipped with an intermediary mechanism which carries the plucking impulse to the comb. This mechanism consists of an assembly of what are called star wheels.
Hence, in disk music boxes the protrusion on the disk strikes a star wheel causing the latter to rotate a notch… and, as it rotates, pluck a tooth in the comb.
However, the star wheel mechanism – ingenious as it is – makes the proper functioning and the longevity of disk music boxes even more dependent on their freedom from dust and dirt than is the case with cylinder music boxes. Ironically, this is because – the dust and or other foreign particles will quickly cause the latter to cease playing altogether, before they can cause damage to the mechanism or parts. Disk music boxes on the other hand – with their robust spring motors - will continue to play longer all the while increasing the likelihood of suffering permanent deterioration from abrasive dirt and grime.
In the early 1970s when I first began collecting music boxes, expert music box collector Etienne Blyelle-Horngacher from Geneva, Switzerland, initiated me in the essentials of caring for and maintaining the interchangeable disk music box. In the present How-To Guide, I’m pleased to pass on to you the valuable information he provided me.
Light Care and Maintenance
Rule N° 1
Take care not to “add dirt” to the mechanism yourself when you handle the box. It is best to brush off each disk before you play it. But even if you decide that following this procedure each and every time you put a disk on your music box is excessively compulsive, you should at least do this from time to time… And also not leave the disks to “lie around” where dust can accumulate on them. But if it does, brush them off before putting them on your music box!
Rule N° 2
Whenever you are compelled to put disks into storage you should first wrap them in wax paper. Do not use plastic a wrapper, as the hermetic seal this material forms can provoke condensation to form on the disk(s). Also do not store them where it is humid, e.g. prefer the attic to the basement!
It may sound like a “no brainer” but you’d be surprised… It’s important to provide proper care to your disks also when they are not in storage. Spraying them with a fine mist of oil will provide good protection; however, it also means that dusting them will be more difficult and need to be carried out more frequently.
Some experts recommend spraying the disks with cellulose varnish; however, this tends to darken them over time and may make them vulnerable to fingerprints. Additionally, these varnishes are difficult to remove later on, especially without simultaneously erasing all or portions of the song title, brand, etc. that are printed on the disk.
Rule N° 4
Regularly clean and check the performance of the star wheels on your music box. While an ordinary clothing brush suffices for dusting off your disks, a small stiff bristled machinery brush is required for cleaning star wheels.
Still, brushing alone is not sufficient. It is important also to have the patience to remove any hairs or other traces of dirt from around the star wheels. This best is accomplished with a pair of pointed watch maker’s tweezers, preferably those with curved ends.
After that, it is equally important to check each star wheel’s performance. To do this - without inserting a disk - close the disk hold-down latch and use a small lever (e.g. a small screwdriver) to rotate each peak of every star wheel IN THE DIRECTION THAT LIFTS THE CORRESPONDING TOOTH IN THE COMB UPWARDS… one after another… making it strike the associated tooth in the comb. As you do this, observe how the tooth lifts and listen to the vibration produced in order to verify that:
Using a small lever to accomplish the above operations facilitates pushing each star wheel slowly enough to immediately stop its forward motion once the tooth is released.
N.B.: If any of the star wheels prove very difficult – or even impossible – to turn, you should not play the music box until this is fixed (see Medium Care and Maintenance below), since doing otherwise you risk to damage your disks and music box .
After you have completed the above checks, if no problems are found, you also should control that the brakes on each star wheel are working properly… That is, that they offer only slight resistance, just enough to stop the associated star wheel from rotating spontaneously due to vibrations provoked in the comb.
Here again it is important to make each peak of every star wheel lift its associated tooth in the comb, because it is possible that only a single peak on one star wheel may offer abnormal resistance… e.g. when one of the other peaks on that star wheel is deformed and catches in the support assembly below it.
BEWARE: When this occurs, it can cause the disk to momentarily bind and then release with a jolt, thereby not only distorting the music, but also potentially damaging the disk and/or the dampers.
Because even the slightest deformity somewhere in the star wheel assembly – even one that’s hardly visible - can result in this problem, great care must be taken to identify the peak that is at fault… and then cautiously straighten it with a pair of small flat pliers which themselves need to be in excellent condition.
Beyond identifying any of the aforementioned problems, this careful 360° rotation of each star wheel also aims to bring to the surface any remaining dirt which earlier escaped attention, thus allowing its prompt removal.
Following the four preceding rules can significantly improve how your disk music box plays as well as prolong its working life.
Medium Care and Maintenance
While “Light Care and Maintenance” consists of procedures that generally do not pose particular challenges, “Medium Care and Maintenance” is a bigger job which you may decide to entrust to a more experienced technician.
In any any event, the procedure is as follows:
Start by removing the combs. To accomplish this, first unscrew each fastening bolt by a quarter turn. Next fully unscrew each bolt individually, placing it into a box with compartments to allow identifying which bolt corresponds to each position on the combs so that they do not become interchanged. This is important because the angle at which the combs were drilled during their manufacture is not always exactly the same for each hole; therefore each bolt may have assumed a slightly different bend at the time it was initially tightened.
Thereafter, each of the star wheels is turned to a position where it is NOT IN CONTACT with its corresponding damper (situated under the tooth it strikes from below when playing). This is the position into which the star wheels normally are placed by the disk at the normal end of a tune.
Subsequently each comb can be detached from the base plate, TAKING CARE THAT IT DOES NOT “PLUNGE” FORWARD IN THE PROCESS. Because if this happens, the tips, dampers and/or tuning weights may be damaged.
Detaching the comb is facilitated by inserting a lever (e.g. a screw driver) into the openings in the base of the comb provided for this purpose, and by inserting a relatively large metal rod into the neighboring hole in the comb. Once removed, THE COMB MUST BE LAID ON ITS BACK ON THE TABLE so as not to risk deforming the lead tuning weights under the force of the comb’s own weight.
Once the combs have been removed, the dampers will be visible. At this point they therefore can be CAREFULLY cleaned using a small brush and pair of tweezers.
Beyond that, as no reference points exist for positioning the dampers, it is not advisable to dismount them. Indeed, if this is done, their re-installation will necessitate successively carrying out a series of adjustments that are quite difficult to accomplish.
Additionally, in no event, should the star wheel gantry be dismounted. The latter often is set on spacing washers of various thicknesses which in no event may be interchanged. Also, the three-dimensional adjustments required to put this assembly back into place will impact on the totality of its operation… And exceeds the framework of “Medium Care and Maintenance”.
At this point you also may decide to remove the motor unit and separate it; however, this is NOT a job to be undertaken lightly. In particular removing the spring risks to have it unfurl wildly which has been known to cause serious injury to the repair-person.
If the motor is to be removed, it is not advisable to take apart the central pivot as, in some cases, this is not mounted on positioning shafts. Therefore, while it’s not unduly difficult to remount it again in such manner that the disk protrusions are properly aligned facing the star wheels, vertical misalignment will cause chords to play as arpeggios with an advance or retard to the base notes. None the less, this isn’t a critical issue, as even an amateur, as long as they are patient and methodological, will manage to find the correct position again.
Begin cleaning the combs by wiping them with a dry rag. If the dirt and grime prove to be very tenacious, the combs can be soaked in benzine. However, they should not be allowed to soak for longer than over night as this can provoke oxidation. A rag soaked in gasoline/petrol also may help to remove grime and surface rust… BUT YOU SHOULD NEVER - UNDER ANY CIRCUMSTANCES – USE AN ABRASIVE! BECAUSE IF YOU DO, THE PRICE OF THE COMB’S NEWFOUND SHEEN WILL BE TO HAVE DE-TUNED IT.
Indeed, retuning the comb thereafter is NOT something that an amateur can successfully undertake; and, even when carried out by an experienced professional, it is probable that the tonal quality will remain diminished. Therefore, it is advisable to keep the combs oxidized as they may be… but playing correctly!
Cleaning the spaces between the teeth is carried out by passing a piece of Bristol cardboard inside them, while at the same time taking care not to overly flex the teeth since the latter can bend and are difficult to straighten again… or even can break.
Once the combs are clean, a thin coat of Vaseline/petroleum jelly should be spread by finger across the entire upper surface and on the tips of the teeth. After that the lower surface can simply be wiped clean of excess Vaseline/petroleum jelly that has accumulated, thereby leaving a sufficient coat there too.
At this point a question of care and maintenance strategy comes into play. Should the star wheels be lubricated? The answer depends on the frequency with which “Light Care and Maintenance” will be carried out in the future… and on the degree to which the music box will remain protected from dust in the setting where it is kept and is used.
Lubrication diminishes the levels of friction and wear when the music box is in use. But it also facilitates the adhesion as well as accumulation of dust and dirt. Also to be considered, household dust is less noxious to a music box than is street dust, which is abrasive.
Expert Etienne Blyelle-Horngacher has estimated that a single rotation of the disk on a “dirty” mechanism causes a level of wear equivalent to 50 rotations on a clean and CORRECTLY lubricated one… Alternatively, if the movement is clean but not lubricated the advantage decreases to 30 for one. Here “CORRECTLY” means lubricated precisely in those places where it should be and with just the right amount of oil. Too much oil will flow throughout the mechanism, clog the dampers and more quickly cause lubrication to lack in places where it would be beneficial. Therefore, when the star wheels are to be lubricated, the recommended procedure is as follows:
Prior to remounting the combs, once again put each of the star wheels into the position where it WILL NOT BE IN CONTACT with its corresponding damper. For memory, this is the position into which the star wheels are put by the disk at the normal end of a tune. Otherwise, it will appear impossible to reassemble the mechanism… and will cause damage to the dampers.
When screwing the fastening bolts through the comb back into the base plate, they should not be fully tightened immediately. Begin by minimally tightening each; then go back and tighten them almost completely; and finally tighten all of the bolts to the end. A good regular tightening of the combs’ fastening bolts will contribute to the music box’s sound quality.
Check that all of the disk pressure wheels - both those in the upper pressure bar as well as those below the disk, are rotating freely. If any of these wheels have become flattened on one side through prolonged storage with a disk left in place, corrective measures need to be taken.
If the flattening is minimal, less than about 2 mm, the extremities can be rounded up with a file. If the flattening is greater than that, then either the upper pressure bar wheels must be rectified or the lower ones remade. In either case, the wheels should be concentric within a tolerance of at least +/- 0 .5 mm… and, if possible, not spaced more than 1 or 2 centimeters apart.
Visually - and then mechanically - check that everything is working properly. If you have removed the motor unit, place a disk on the spindle and turn it SLOWLY by hand, remembering that quick movements can provoke damage or breakage.
Finally inspect the protrusions on your disks, and, using a small pair of parallel pliers which are in good condition, readjust any that are bent out of shape. Should any protrusions be too badly distorted to be put back into form, they are best removed in order to prevent the protrusions which follow from jamming. N.B.: A method exists for soldering on replacement disk protrusions. The process requires care but is not overly difficult to accomplish.
What you have accomplished above will prolong the life of your valued disk music box as well as ensure that, musically, you continue to derive optimal pleasure from it.
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