Dice Tray Project

For project 1 for 3D modeling and Digital Fabrication class I decided to create a dice tray. I had trouble finding something artistic to do with this project, but I had a bunch of ideas for tools and useful things. I decided to make a tool artistically. Voila! Fancy dice tray.

First up, drafting the basic pieces of the tray. I started with a basic hexagon, then put an inner trace and an outer trace around it to create a 1/4" wide shape. I parted out the shape to create a smaller shape of the boarder that had only 2 sides and a single vertex of the whole hexagon. I measured out the placement of the screw holes along the center-line of the boarder, the first 1/4" in from the end, and the second 1/2" from the end.

I drafted the circles image featured on the baseplate from a video that Numberphile did on YouTube about the concept of circle inversion. Video here: https://www.youtube.com/watch?v=sG_6nlMZ8f4

After parting out each wall piece, I duplicated it in triples to form whole layers of hexagonal walls, and nested them together as best I could while still fitting the hexagonal baseplate on the same sheet of acrylic.

Looking at all the acrylics on Inventables.com, I decided to make the walls out of red and black acrylic, the support base out of black acrylic, and the decorative base out of two toned acrylic, aluminum on black. The Al on black only came in 1/16" thickness, which necessitated the black support base underneath.

I created separate files for each color of acrylic to better organize my thoughts, my process, and to reduce the chances of mistakenly cutting the wrong file from the wrong plastic.

Black Acrylic File:

You’ll notice that there are more shapes than just the walls and hexagonal base on that file. I added cuts to produce a series of point counters to utilize more of the available area of the acrylic sheet I purchased. I also had to change the green lines to blue to make the laser happy.

The red acrylic file:

This file only has wall pieces. I decided that since the support base wouldn’t really be seen, I’d cut it out of black, leaving more area of red for any future projects, black being the cheaper of the two sheets.

The Al on black acrylic file:

An interesting thing happened on this cut. You’ll notice that on every file that has screw holes, they’re a different color than the hexagon. I thought it wiser to cut the screw holes before the hexagon so if the larger piece dropped or shifted, the screw holes would still be accurate. On every other cut, the red line cut before the blue line. On this cut, the blue line cut first. Thankfully, the large piece didn’t drop or shift, so the screw holes remained accurate.

I cut the prototype out of cardboard to test placement and fit, however the settings listed in the materials bible didn’t quite cut all the way through, causing the pieces to rip when I attempted to separate the pieces. the pieces that were intact seemed to fit well. I didn’t get photos of this prototype.

The first cut I did was the black acrylic.

In the above picture the laser has already cut the red lines outlining the screw holes. The “+” shapes are tabs to secure the point counters, and are unrelated to this project.

Next was a dry fit of the pieces and hardware.

Seeing all fitting well, I proceeded to cut the red acrylic. At this point I realized that the original Al/black acrylic sheet I bought was too small to fit the decorative bottom. I ordered another, larger, piece that evening.

On to the final assembly!

Hardware you’ll need:

168x M3 machine washers, 24x M3 Nylock nuts, 24x M3 Acorn nuts, and 24x M3/30 .50 thread bolts.

All the pieces:

Also appearing, a ratcheting screwdriver, a small pliers, a reverse tweezers, and a fine Phillips screwdriver.

First up, put a washer on each of the bolts, and place them through the first wall piece.

Flip the pieces down so the threaded end of the bolts faces upward.

Apply washers to each bolt, and lay out the next layer of wall pieces.

Place the next wall pieces so the vertex of the new piece joins two of the originals. I will be placing the right most piece first.

Alternating the end points of the wall pieces strengthens the overall structure, and resists twisting and warping. Assemble the next two pieces, jumping an endpoint, and place more washers.

Repeat, alternating endpoints and washer/wall layers.

After 5 layers, place the decorative bottom piece. As the overall piece is symmetrical, the orientation is immaterial.

Place the bottom support piece.

Put the Nylocks on the bolts.

Before tightening, inspect your work. Double check that you have only one washer between each layer of wall piece. The little buggers love to stick together, and may cause the acrylic to crack when you tighten the bolts.

Tighten nuts and bolts until firm. Be careful not to over tighten, as you may crack the acrylic. Just in case, I made spares.

Tighten the Acorn nuts down to finger tight over the Nylocks. These become the feet of the tray as to not scratch the bejezus out of the surface you put the tray on.

Congratulations! You now have a completed dice tray!