Anyone knows how music box drums are made? 3

[mforoutanfar]

Hi everyone,

I was wondering if anyone knows how music box drums are made.

From what I've seen in a video, one type is basically a metal sheet rolled into a hollow cylinder. Small holes are drilled on the cylinder. Then, wire is inserted into each hole and is trimmed. The cylinder is then filled with resin to fix the wires in place. This forms the "pins" that, when the drum rotates, hit the musical "comb" and produce music.

However, I have this music box whose drum seems to be manufactured differently. The pins seem to be welded or formed directly on the drum (see pics below).

http://farm6.staticflickr.com/5121/5303387162_8e0380b36c_z.jpg

http://thumbs.dreamstime.com/x/closeup-old-music-box-movement-drum-tines-12781483.jpg

On the inside surface of the drum, there are very shallow depressions where the pins are located, and there's of course no resin or anything.

Does anybody know how this second type is manufactured? Thanks.

 

[IRstuff]

The options could be:
> pressfit pins
> stamped -- some sites say it can't be done
> molded?

One very interesting possibility might be to 3D print the cylinder

TTFN
faq731-376

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[GregLocock]

soldered studs

Cheers

Greg Locock


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[mforoutanfar]

Thanks for your reply IRstuff.

Can you give me the link to those sites you mentioned?

As for 3D printing, that's indeed an interesting idea. Do you thing the material is strong enough though? (I'm not familiar with the material used) Will the pins withstand the stress of the strokes in the long run?

 

[3DDave]

Tiny stud resistance capacitive discharge welder? Little ones are used in making dental work and putting solder tabs on battery packs. The depressions could be from the electrode pressing on the inside surface of the cylinder. I think the drill and fill method is chosen for its clean appearance - the cylinder surface will be unmarked, but welding is cheaper so you see the welding in low end units. It could be solder, but I don't think solder is strong enough and it would not leave marks on the inside of the cylinder.

This is a page from someone who felt they succeeded

http://www.unity303.com/musicbox/

using polymer clay and a small drill. I would think an attractive unit might be made with acrylic rod and music wire pins.

 

[Compositepro]

The drums that are made in large quantity are die cast (your first picture).