I love listening to music, but i'm terrible at playing it. However, I've always appreciated the simple rattle/shaker , or Maraca, a frequent instrument in Latin music.

I found several models of Maracas online, but the assembly or printing always seemed a bit tricky, requiring rafts, alignment procedures, or other setup that made it seem like a chore to make. Additionally, I wanted a traditional looking design instead of something that looked like it was designed just for 3D printing. To fix this, I designed and optimized this Maraca to be an easy 3-part print that's tolerant of typical issues with FDM printers (like overhangs and first layer bulging ruining screw threads).

Printing

• I printed in PETG @ 0.16 mm layer height, however variable layer height would also work well with this print. PLA should work fine (or maybe better) too. If you use thicker layers, the parts that need the thinner layers are the threaded areas of each of the parts, and the top of the shaker body dome.
• There are 3 parts, the screw, the shaker body, and the handle. Shaker body and handle should be oriented flat-side down on the bed.
• Avoid brims if possible, or else you'll need to clean them up for a pretty result. I was able to print in PETG without them. Printing-by-part instead of by layer helps ensure you don't get collisions.
• The screw print orientation is important, as one side is specifically designed to be on the bed to avoid issues with the threads. Print with the labeled “up” side facing away from the bed, as pictured here:

Assembly:

• The screw features a hex driver hole on both sides to allow for easy installation into the recessed threaded holes on the shaker body and handle. I recommend using an M6 allen key or screwdriver to drive the screw first into the handle until it bottoms out and then screw the shaker body/top on to the handle+screw. Orient the screw so that the “Up” imprint faces the shaker body/ top.
• After confirming assembly fit, fill the shaker head with rice, cous-cous, or beans. Experiment with different fillings to change the sound.
• Note that the screw may be a little tight at first.. working it back and forth with a hex wrench a little should loosen it up nicely. If it doesn't a touch of grease on the threads should do the trick.
• If you have any trouble with your printer's first layer mush screwing up the threading fit, try running a deburring tool or knife around the inside of the threaded holes on both the handle and top, and this will likely allow the threads to mate easily.

Design Notes:

• The screw has chamfered relief on both sides to ease driver insertion and has been tested to fit an M6 hex driver snugly.
• If you apply a drop of glue before inserting the thread into the handle, you can be assured the thread will always come out stuck to the handle instead of the top. This is purely optional. The tension of the two sides pulling on the screw in opposite directions will keep the maraca together without any need for glue.
• The screw has a thin offset and chamfer built in on one side (opposite the “up”) to make sure a first layer smush doesn't screw up the threads. It's much easier to ream out the holes a little than it is to trim down the thread to get it to fit in the case of issues.
• The top is not spherical to minimize issues with overhangs on the inside.
• The handle and the shaker body both have screw-stops built in to prevent the screw from going too far.
• STEP and Fusion 360 files provided in case people want to make adjustments.