MAS 863 - How to Make Almost Anything Fall 2004

Amon Millner

millner [at] E15-020F, 20 Ames st, Cambridge, MA 02142
Weekly Assignments

The Magic Maracas

Inspiration I thought it would be interesting to make a press-fit object with sides that don't meet at a 90 degree angle
Project files magic maracas sDraw file dump

*in order for the maraca pieces in the files to fit together after you cut them out, you may have to do one of two things: (1) try changing the speed and power settings on the cutter (because the tiny amount of material the laser blasts away can alter the press-fit strength); or (2) tweak the "tabs" on each piece that presses together


Look how fun it is to shake this magic maraca!! The inside of the press-fit maraca is full of acrylic scraps. Scraps bounce around to make music we all know and love.


This close up shows how all the parts fit together (parts are shown below). It was tough to make sides that meet each other at a 45 degree angle (that's why boxes are popular projects). I thought through how the dimensions of many parts of the maraca would fit together (taking into account how the laser would alter the actual size of the physical parts). For the sides that meet at an angle, I found trial and error (using cardboard first) useful. 


Here is a look at the bottom. Notice the clamp where the handle meets the noise-maker. There are slots in the handle for this clamp to go through - inserting the clamp forces the handle to expand to make a SUPER SNUG fit into the noise-maker. This is to ensure safety in case someone wants to use this as a baby rattle. We don't want the top flying off and letting the dangerous-if-swallowed acrylic parts leak out.


In this photo, you'll see the output of the maraca's sDraw file. Cardboard is a great way to test how the pieces fit together. It is usually easy to find cardboard that is 1/8" thick if you plan on using 1/8" acrylic sheets. Two things to keep in mind that the settings on a laser cutter influence how parts fit together. For example, a laser can move quickly over cardboard using a low power laser (50%) and still cut it. It may take more power and slower movement to cut acrylic pieces. Playing with different speeds and powers alters how much material is melted away while cutting. This is important to note because you still may have to make adjustments after the cardboard fits snuggly (as I had to - see the picture below).

The parts shown are: tabbed noisemaker sides (8 needed); handle slots (2 parts); top and bottom handle clamps (using 1 worked out well); noisemaker top and bottom (the bottom has an insert for the handle and slits tabs)

Process notes/tips -tool settings: to cut a 1/8" sheet of acrylic, I set the power to 100 and the speed to 10 on the Epilog laser cutter.

-making good tabs is an acquired skill. I relied upon keeping a sDraw file that has each side of the maraca laid out  as overlapping rectangles that haven't been merged or subtracted yet. When I needed to change the tab sizes, I would go to the properties of each tab and modify the size by a millimeter or two

Things to think about

Cardboard gives way to pressure a lot more gracefully than acrylic does. When I first tried acrylic with slot sizes that worked for the cardboard prototype, the pressure I put on the handle while trying to jam them together caused it to break. It doesn't do much for your project, but it's a great stress reliever ;p