Introduction: Mad Chopstick Burr

When we heard that the latest challenge was chopstick based a friend said to me that I should make "one of those mad pencil thingies but with chopsticks rather than pencils".  I finally managed to get sense out of him and he directed me to this website and the amazing work of George Hart:

I sourced some super cheap chopsticks from ebay and set about making my own slight variation.  I knew I could not use exactly the same design as the chopsticks where not hexagonal cross section like pencils and they tapered.  So rather than the 72 pencils of George Harts original creation - I went for 76 chopsticks in a solid three to the edge hexagon rather than empty 4 to the edge

Step 1: Craft Temporary Rigs I

First you need to get the spacing of the chopsticks straight - in your head and then on paper.  Each set of chopsticks fits through each other set at a 60 degree angle.  This part does not need to be absolutely millimetre perfect - after drawing lines at 30 degrees apart on a piece of Westfoam 5mm foam board,
1. To avoid ripping paper make a tiny cross cut in the board (much smaller than cross section of the stick) at the point where the tow lines meet.
2. Supporting the board push one chopstick through 
3. Lie a chopstick flat on the board and ensure it is point at around 60 degress
4. Draw around a second upright  end of chopstick
5. Repeat with another to get a good idea of the separation needed.

Step 2: Create Temporary Rig II

Now you know the separation you can make a grid - this has nineteen nodes.   Carefully using a sharp point - it doesn't have to be too sharp, I used as sharpened  4H pencil.

Step 3: Create Temporary Rig III

You can then use first hexagon as a stencil - poking through each hole to mark a layer below.  You will need eight of these 

Step 4: First Dimension

Always being careful to support the board start pushing the chopssticks through the first rig.

As the chopsticks are not the same down the entire length (ie they taper) it matters which way round they are I decided to have all the corner sticks in the same direction and those in the middle of the side in the opposite.  The ones in the centre I alternated direction.

After the six corners and the centre I added the other rig and gently pushed through the others.  You should end up with nineteen chopsticks held firmly in place by the board rigs at each end.  You can note from the photo that there are clear gaps through which you can see/stick next set of chopsticks

Step 5: Second Dimension

With a new rig - push through all six corners and the centre chopstick.  You now need to slot the open ends through the open gaps you could see in the picture.  Add the other rig at the other end - and fill in all nineteen spaces.   It becomes clear which holes each goes through.

Up close you can see that another set of holes that the next dimension will fit through.

Step 6: 3rd Dimension

Fit another seven in a rig and feed through holes in the last close-up.  Add the other rig and fill in the rest of the 19.

Step 7: Into the 4th Dimension

You will have noted from the last closeup of the previous set and the pitcure below  the holes for the final group are quite obvious.  Its best to still use a rig - to make sure you get everything in the right order.  

After the last set are through (which I forgot to photo) - put elastic bands around the end of each group (I managed to photograph that)  and very carefully remove the rigs.

Step 8: Remove the Evidence

The last stage is to tighten the band a bit by adding a few more bands - this will bend in the sticks slightly .   You want the chopsticks to be under a bit of tension.

Any of the interior that are loose can be fixed - by giving a little twist. As they are square the twist will tend to lock them in place

Then a thin band of see-through acetate (I used a hacked up cover of a presentation folder is wrapped next to the rubber bands and secured with a small bit of see through Scotch Crystal tape. Do this for all eight ends - before removing the bands.  As the tension is released from the bands then acetate strip with take the strain and be held tight.  

This is almost invisible - i have tried to get a snap of it.  Mostly you can only see it when the light reflects off.  

Step 9: Final Look

With all the bands taken off and the acetate on it looks pretty good - and I am convinced that if dropped it would explode into 76 chopsticks .