[ Jody received this request from Mr. Andrew Young. Since little on
[ this topic has appeared in MMDigest we asked Ralph Heintz if he
[ could respond. An expert restorer of musical boxes, he also serves
[ as technical correspondent for Musical Box Society International
[ (MBSI -- http://www.mbsi.org/). Thanks to Mr. Heintz for kindly
[ sharing his knowledge with MMDigest. -- Robbie
> I have a music box that needs to be oiled and I have a question about
> the shaft that is directly in front of the mainspring (holding a
> wheel with teeth that spins around). I think that is the culprit
> that is causing some noise between songs on my movement. I am not
> sure though. Can you move this wheel to the right or left? Any
> info would be appreciated. Thank you. Andrew Young
Dear Andrew: I have been asked to add a few words on your questions
regarding "non-musical" noise in modern musical box mechanisms.
As you have discovered, the noise generally emanates from the
(1) "governor" assembly, consisting of the "air brake" or fan;
(2) the worm (referred to in England as the 'endless'); (3) the worm
gear, that meshes with the worm (on a longish, horizontal shaft with
a very small spur gear at the other end); (4) a "step-up" gear that
increases the drive speed to the worm; and (5) a framework that holds
the whole mess together.
Although this type of governor system has been used in musical boxes
for over a century, it remains a mechanical engineer's nightmare. No
self-respecting engineer would ever dream of driving a worm with the
worm-gear. It is always used the other way around as a speed
_reduction_ device; yet it works here, and has worked so well that no
one has come up with a better device in the history of musical boxes.
With this as background, then, you have already noted that the fan
rotates quite rapidly -- it literally "beats up" the air in order to
put a brake on the rotation of the cylinder. Otherwise, the cylinder
would spin with all the force of the mainspring behind it and both the
cylinder pins and the musical comb would be destroyed.
The rotation of the fan is what causes the whirring noise, just as do
the blades of an electric fan or a rotary blower. It is something that
can't be escaped, although it can be minimized by a cover such as the
glass on your 3/72 movement. The sound of a smooth-running governor
is an indication that the drive system is operating properly.
Lubrication in very small amounts can reduce gear noise, if that is
adding to the noise problem. I would _not recommend_ using "3-in-1"
oil or sewing-machine oil under any circumstances. They become gummy
over the years and can slow down the governor or even keep it from
operating. A good watch oil is probably best, applied sparingly to the
pivots. I have also found that a light, molybdenum-disulfide grease
(e.g. "Molykote G"), applied to the worm wheel and brushed to remove
all but a minute film, will sometimes give smoother operation, but
I think you are pretty well stuck with the fan noise.
Regarding a cover over the governor, I feel that this would be an added
expense that the manufacturers would not care to absorb. It would not
buy much in noise reduction, and it would complicate access to the
governor for cleaning and lubrication. As I mentioned, people have
been making musical boxes this way for more than a hundred years and
are not about to change now. The high cost of Reuge movements reflects
the cost of Swiss labor, and the company does everything in its power
to reduce the cost of manufacture.
One word of caution in closing. The governor should _never_ be removed
unless and until the mainspring is _completely_ wound down. There is
no reason to remove it anyway, unless there are other problems with the
movement, such as gear damage or a broken mainspring, and those repairs
should be handled by a qualified repair person. The same holds for the
comb. The comb position has been set at the factory, and it has
nothing to do with the drive mechanism, so it is best left alone.
I hope this will provide some help with your questions.