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Sankyo 50 and 72 Note Music Box Design & Installation Considerations

This document is a mix of Sankyo's instructions and our own experience. We hope they will be helpful to you. Most important to designing your music box will be the Dimensional Requirements PDF Drawing. A ways down below is the "Box Design Considerations" heading, which elaborates on the PDF. Using Glass is important, as it enhances the bass resonance as well as protecting the movement from fingers and dust.

Sankyo has individually precision-machined, assembled, and adjusted each movement for optimum musical performance and satisfaction. We personally inspect and play each movement before shipping it, and on occasion make adjustments necessary for optimal performance.

Please be careful to handle all movements with care to avoid getting skin oils and acids on surfaces that could corrode. Pay special attention to not bump the Governor, as you may inadvertently change the tempo. Do not allow movement to play when sitting on cloth, bubble-wrap, etc., as they may catch on cylinder pins and be drawn into the comb!


 

Music Box Movement Components (Glossary)

Spring Housing (or "Spring Cage")

 

 


Winding Shaft comes out the bottom of the spring housing. The Winding Key screws onto the winding shaft. A 3/8" (10mm) Key Extender is available if needed.

#2 Gear or "main gear" (at the left end of the cylinder) engages the gear in the bottom of the spring cage and the governor gear.

On top of the spring cage is the "Geneva Stop". It stops the spring before it winds down completely.

 
  Governor
   
The friction governor assembly consists of gears and a "rubber" fan or governor.  Its purpose is to maintain consistent speed regardless of spring tension or number of notes being plucked at once. Pay special attention to not bump the Governor, as you may inadvertently change the tempo.

If the governor breaks, the cylinder will spin at very high speed, usually breaking teeth on the comb and "stripping" the cylinder (bending many of the pins), thus ruining the movement. This will only happen due to physical abuse or the use of oil containing solvents which assault the integrity of the "rubber" governor (which is not really rubber, but a material with superior properties).


  Cylinder

   

The polished cylinder (otherwise called the "Tune Drum") is drilled and hand-pinned.

The Pins protruding from it are held in place by epoxy inside the cylinder.

The pins lift the teeth on the comb and then drop them.

The resulting vibrations in the teeth produce the beautifully ringing notes.

  Comb (or "Vibration Plate")
 

 


The Teeth on the comb are individually tuned.

The bass teeth (on the left end of the comb) have Lead Weights to lower the pitch.

All but the highest notes (right end of the comb) have Dampers glued to the bottom of each tooth. Without dampers, these teeth would buzz when coming in contact with a pin before they had stopped vibrating from the last time they were plucked.

  Stopper Lever (or "Feather")
 

 


The spring-mounted stopper lever stops the mechanism at the end of each tune by engaging the hole in the #2 gear. When the On-Off Lever holds it to the right, the movement plays tune after tune continuously.

 

Handling

Avoid touching the movement parts with your bare hands, especially the comb and cylinder.

 

 

Some parts of the movement are susceptible to corrosion. Human perspiration contains salts and acids that can promote corrosion. It is common to see old musical movements that have some rust, and many no longer play well because of corrosion.

If you accidentally touch the comb, you can gently brush some clock oil on it with a small paint brush. Keep lubricants away from the black, rubber-like governor, as they WILL damage it. Do not use WD-40, 3-In-One, or other oils that contain solvents, as they WILL damage the finishes.

The cylinder pins, the comb "teeth", the gears, and the governor assembly are very delicate and can be damaged, so be careful.

 

Safe Handling

Store the movement in its original packaging in a dry, dust-free environment until installed in your box. Remove the cardboard piece at the right end of the cylinder before you play the movement. Be careful not to touch the governor, comb or cylinder. Try to touch only the cast base plate (as shown). Be careful not to let the movement slip out of the case!
 
 


  Readjusting any part of the movement, modifying the movement in any way, or re-oiling with the wrong oil is not recommended, think twice! An occasional cleaning and lubrication by your local clock repair shop is advisable. Please warn them that the black, rubber-like governor can be easily damaged by lubricants. He will apply a light clock oil sparingly to the metal-to-metal wear points.
     
 

Box Design Considerations

See
Dimensional Requirements PDF Drawing
in conjunction with the information below.

Box Material

 

 


Do not use extremely hard (e.g., Ebony) or extremely soft material (e.g., Balsa) because the acoustical amplification properties of these types of wood are not good. Walnut and Cherry are good choices. Generally, more dense woods amplify bass resonance while lighter weight woods are stronger on the treble end of the range.

Choose a wood that is sound, stable and dry (around 4-5% humidity). You don't want wood that will warp or that has hidden cracks.

 

  Box Bottom or "Resonator Strip" Material (the most important element to the acoustics of the box)

 


Thickness - 3mm - 10mm (nominal 1/8" to 3/8"). The thickness of the box bottom affects the volume and timbre. 1/8" (3mm) to 1/4" (6mm) seems to resonate best in most woods. Most older, quality music boxes have a full bottom about 1/8" (3mm) thick, with 1/8" (3mm) wood strips added on top of that bottom at the front and back, leaving a "trough" down the middle (running from left end to right end). These resonate very well.

 

It is best to mount the movement right side up and horizontal. However, tilting it up to 90 degrees is OK, as long as the cylinder axis remains horizontal (see below).
 
                        Best                                        Good                                       Poor





   
Bottom Thickness
- 3/8" (10mm) maximum without key extender, 3/4"(20mm) maximum with one key extender. 1/8" (3mm) -1/4" (6mm) seems to work best in most cases.


Mounting Height
- the distance from the top of the resonator strip (the movement mounting surface) to the support surface (table) should be at least 11/16" (18mm) to keep the key from rubbing on the table.


Operating Lever Dado
(Inside the front of the box)

 
   

           Height: 3/8" (10mm): the operating lever is 10mm (3/8") so make sure it will slide freely.

           Depth: 1/8" (3mm)- 3/8" (10mm)


Top of Resonator Strip to Bottom of Dado
: 9/16" (15mm) to 3/4" (20mm).


On-Off Button Hole Diameter
: 1/4" - 5/16" (6 - 8mm): big enough so the lever will slide, but small enough so it doesn't show behind the "Lyre" button.


Box Front Thickness:
Dado depth plus 3/8" (10mm) is required for Operating Lever to work properly. Dado need not be very deep.


Location of 3/16" (5mm) holes in the bottom of the box
, see template (we send one with your order).


Face of box to front edge of movement base plate:

7/8" (22mm): you'll need to trim the stopper lever (feather). To avoid having to trim, 1 1/8" - 1 1/2" (29mm - 33mm) will work fine, but your movement won't fit quite as tydily in the box: it will have more room around it.

Glass:

Using Glass is important, as it enhances the bass resonance as well as protecting the movement from fingers and dust. The movement is 1 1/4" (31mm) high, so your dado for the glass should be perhaps 1/4" (6mm) above that..
 
Rattling or Buzzing
    All four feet need to sit solidly on the table. Thin felt pads on the feet will eliminate most rattling and buzzing. Note: most tables are not perfectly flat, so even if your box is perfect, felt pads are still a good idea.

Use a cushion to prevent glass from rattling or humming inside the box. A short piece of rubber band works well. Small scraps of dried silicone caulk work even better.
 
 


Assembly

Clean the Inside of Box

 

 


Make sure that there is no dirt or dust inside the box. (Use a blast of air or a vacuum to remove the dust.)

  Clean the Movement
 

 


If your movement needs cleaning, clean it with suction (a vacuum) or low-pressure air, avoid fingerprints, and be careful. A natural bristle brush may be used on the cylinder. A small soft paint brush can be used to apply a light coat of clock oil to the comb (follow the direction of the grain) if you've gotten fingerprints on it, but be careful not to get oil on the cylinder, as it is hard to remove.

 
Mount the Movement in the Box
   
Use our Drilling Template to locate the holes correctly.

Handle the movement only by its painted baseplate.

Use all three screws and lock washers, applying a tightening torque of around 10 kg f-cm (solidly snug).

  Mount the Operating Lever
   


The long operating lever is designed to be customizable to your requirements. Usually the hole for the "lyre" button is horizontally centered on your box. You'll probably need to clip off the end of the soft aluminum operating lever and bend it in the right place to fit your box. We're sometimes able to ship a short lever with 50 note movements that works without modifications.

The clearance between the Operating Lever and the Stopper Lever should be about 1mm (1/16") when in the off position (slid to the left).

The nylon washer goes on the outside of the box, to protect the finish on the face of the box.

Make sure the Operating Lever does not cause the point of the Stopper Lever to lift and ride up on the top of the Spring Housing. If it does, you may need to twist the operating lever slightly so it lifts the tail of the Stopper Lever when engaged.

 
 

When Shipping a Finished Music Box, it Should be:


    Wound Down - Geneva Stop engaged (so it won't accidentally play if jarred during shipment).

Between Tunes - Stopper engaged (so the pins on the cylinder and the teeth on the comb don't damage each other):
1. Let the movement wind down all the way.
2. Wind it one click at a time and let it play until it reaches the end of the tune.

Right side up and well padded

Shipping damage usually results from severe jarring or from pins interfering with comb teeth during shipping (e.g. if it plays during shipping).
   
   
 

Storage

 

 

Store Musical Movements as packed, in a dry place with fairly stable temperature. If you have to store Musical Movements unpackaged, cover them so that humidity, dirt, and /or dust cannot settle on them.


 

Installation Parts for 50 or 72 Note Sankyo Movement

For fastening the movement into the box:

 

 


Screws - 3 ea.

Lock washers - 3 ea. (Usually used just under the screw head)

 
Operating lever

 

 


L - shaped metal piece with slotted hole: may need to be cut to size and bent to fit your situation.

Spring (thin steel with slotted hole and slight bends, goes just under the L - shaped piece. Its tension keeps the lever tight enough, while still letting it slide easily)

Operating "Lyre" button (with threaded shaft)

Nylon washer (goes under the head of the "Lyre" button to protect the wood face of your box)

Nut (to hold them all together. Make sure the spring and L - shaped piece are properly seated on the flattened part of the lever button's shaft, then tighten the nut securely)

 
Winding Key

Decorative Tune Label


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