Overview

A fully printable, fully functional printable harmonica in a simple 3-piece form factor that clips together - no fasteners needed! The design features swappable reed plates which set the playable notes. The attached reed plate has been painstakingly tuned to an A-minor scale, starting at A4 through to A5. I'll be adding additional reed plates in future updates to offer more note groupings. Better yet, feel free to try out your own designs using this model as a template (step files attached).

The current version does not incorporate draw reeds yet, only blow reeds.

UPDATE - 28/MAY/2023: Now with a print-in-place carry case

Print Instructions

The reed plate is very sensitive to the material, the printer and the slicer settings - a decent first layer is crucial! The clearance between the reeds and the plate must be as small as possible for maximum sound efficiency without being too tight as to interfere with the motion of the reeds. The reeds must be completely free to vibrate up and down within their gaps without coming in contact with the plate. I'd recommend you print the reed plate solo to avoid other parts interfering with the reeds.

The comb and cover are less fussy and don't need as much care. Use your favourite filaments and settings as usual.

Here's my recommended setup:

• Printer: Prusa mini+
• Bed: PEI smooth spring steel sheet
• Filament: 
  • Reed plate: Polymaker PolyTerra PLA in Charcoal Black
  • Cover: No preference
  • Comb: No preference
  • Case: No preference
• Bottom layer count:
  • Reed plate: 1
  • Cover: No preference
  • Comb: No preference
  • Case: No preference
• Top layer count:
  • Reed plate: 2
  • Cover: No preference
  • Comb: No preference
  • Case: No preference
• Infill:
  • Reed plate: Gyroid, 15%
  • Cover: No preference
  • Comb: No preference
  • Case: No preference
• Layer thickness:
  • Reed plate: 0.2mm
  • Cover: 0.2mm
  • Comb: 0.2mm
  • Case: 0.2mm
• All other settings: Prusa Slicer 0.2mm quality profile defaults

Print Orientations

Reed plate

Comb

Cover

Case

Assembly Instructions

See the attached video for a good visual on assembly.

1- Attach the reed plate to the comb by sliding the reed plate under the rear lip of the comb and pressing down on the slotted holes until the plate is completely flush with the top surface of the comb. This joint should be as airtight as possible for max volume.

2- Ensure the clips on either side of the comb are free to spring backwards. They may need be loosened up after printing.

3- Push the reed plate and comb assembly into the cover until the clips click into plate.

4- Play some sweet tunes!

Customisation

Use Prusa Slicer's new text feature to add your own text to the comb! Import the attached “comb_blank.stl” into Prusa Slicer and add your text to the blank back face of the comb.

Alternatively, use your favourite CAD software to make the mouth organ your own!

UPDATE 28/MAY/20234: Carry Case

Simply print the form fitted print-in-place carry case, pop it off the build plate, loosen the hinge and use it to securely carry your mouth organ!

Happy printing!