Rubik's Cube
43,252,003,274,489,856,000 permutations
The idea of building a working Rubik Cube has always appealed. Here the
challenge is to create a mechanical device that has a number of degrees of
freedom about a central point. It's not easy! The cube consists of 12 edge
pieces, 8 corner pieces and one central piece. All of these have to be
interlocking, yet still be able to rotate about any axis at any time in any
direction! And all this with a basic square block! Thankfully LEGO has been
kind and the ratio of 5 bricks to 6 studs allows us
to create a genuine cube structure.
I must point out that quite independently a fellow LEGO enthusiast has also
constructed a working Rubik's cube. Maarten Steurbaut's cube is quite a bit different from mine. His original
design is based around 8x8x8 cubes and so it's slightly larger than my
cube. After seeing my version Maarten went on to create a Rubik's cube that's
smaller than my one based on 4x4x4 cubes. The challenge now is to get proper
corner pieces into the 4x4x4 version.
Rather than boring you with endless detail of how a Rubik Cube works it's
probably better just to scroll down or use the links to jump to a specified
sections and see how it was constructed. There's even a movie of the
Rubik's cube in action - its operation is a bit sticky due to there being
slightly different levels between pieces (a result of not having enough tile
plates), and self-destruction was always a possibility!
Inside a Rubik's cube is a mechanism that has six stems coming from the centre.
Each of these stems a centre piece is attached. These pieces can rotate with
the stem being their axis of rotation. T
The edge pieces have to lock between two of the centre pieces, but allow the
corner pieces to slide past them when one face is being rotated. There are
twelve edge pieces in total.
A Rubik's cube has eight corner pieces. These were the most difficult part
to make since the square nature of the LEGO brick doesn't lend itself too well to
the creating circles. The corner pieces have to move completely round the
entire cube as well as ensuring the whole puzzle remains self-interlocking (ie.
it doesn't fall apart).
There are four photographs of the whole Rubik cube. Three are the basic LEGO
model and the fourth has the stickers attached. The whole cube was pretty big,
which meant trying to do it very difficult. In fact the whole model was
prone to self-destructing, something that could only really be solved by using
glue. I also didn't have enough tile pieces. The consequence of this can be
seen in the movie of the cube in action. Basically, it meant that some of the
centre and edge pieces had at fractionally different heights than their
neighbours, resulting pieces catching when rotating.
For completeness I've also added a few photos of the cube being constructed.
There are a LDRAW CADs for the different parts and step-by-step instructions on how to build it.
