Instructables
27 3/4" clear acrylic cubes are drilled with 108 3/16" holes, fitted with 108 D32 neodymium disc magnets with proper polarities facing out from each, and assembled into a size-matched magnetic version of the original Rubik's Cube.


Update: Instructables user burzvingion has made a beautiful red translucent dice version of this cube. Make sure you check it out!


Tons more pictures of the process can be seen in

The pre-build gallery:
http://flickr.com/photos/garyfixler/sets/72057594101653870/

The build gallery:
http://flickr.com/photos/garyfixler/sets/72057594105668430/
 
Remove these adsRemove these ads by Signing Up

Step 1: Plan out polarities

Before I devoted my time to this idea, which came to me while imagining a version of the cube that didn't need the intricate connecting tabs found inside a cube, I checked Google for magnetic rubik's cubes, finding none (though a friend found one (theoretically) available in China by removing the 's from rubik the day before I finished this thing). Then I mocked up a 3D version in Maya to figure out the polarities of the magnets to see if it would remain sound as faces were spun all around. It appeared that it would.

Step 2: Get some cubes

I researched cubes of all sorts online, including wooden blocks, "learning cubes," cubes of ABS, PVC, etc, and finally settled on 3/4" clear cast acrylic cubes from Tap Plastics:

http://www.tapplastics.com/shop/product.php?pid=136&

I got 3 sets of 10, as I needed 27. The extra 3 helped me test things out, which saved me some big trouble. These aren't all that precise, with romboid and trapezoidal angles aplenty, but in the end, they work well, especially as they're nicely rounded.

Step 3: Get some magnets

I found K&J magnetics through Google:

http://www.kjmagnetics.com/

They have a huge selection, and I settled on their D32 3/16" disc magnets, which are 3/16" tall.

http://www.kjmagnetics.com/proddetail.asp?prod=D32

I got a pack of 100, and a pack of 25. I needed 108 for the cube prototype. If I build another, I'm going to beef up 12 of the magnets - the 6 pairs that form the axles off the center cube, probably to twice the width, perhaps to the D63:

http://www.kjmagnetics.com/proddetail.asp?prod=D63

Step 4: Set up the drill press

I don't have a shop at the moment, so I had to settle on a cheap drill press on the dining room table. I used a needlessly high-precision CNC-milled clamping square from Woodpeckers, makers of fine, high-tolerance machining guides:

http://www.woodpeck.com/groupclampingsquare.html

They have a feast of uber precision stuff:
http://www.woodpeck.com/

I held the clamp guides in place with some small Irwin Quick-Clamps, and later, for some more stability, with standard metal C clamps.

To align things, I eyeballed it: I'd get it about right, clamp it down, then press the non-spinning bit into the acrylic to make a tiny dent, then turned the cube 90 degrees and pressed again. When I got this to make a perfect tiny X in the acrylic, I knew it was pretty good. The cubes aren't accurate enough to be bothered with anything more precise than that.

Step 5: Get your polarities straight

It's crucial that all these axially-polarized disc magnets are put in the right way, and I'm glad to say I didn't mess this up once in all 108 magnets. To keep me straight as to which side of each magnet was which, I stuck them all together in one long rod, then drew a Sharpie dot on one end, and peeled that magnet off, and repeated, all the way down. Now they all had a visible polarity, though I don't know still which was N or S.

Step 6: Drill out the central piece

The central piece requires 6 holes, one per side, dead center. At first, I tried using a drill stop clamped onto the bit itself, but this is disasterous. The acrylic going up the flutes gets caught in there, and becomes a heated spinneret of fibers that instantly wraps around the bit, creating a solid acrylic chamfer between the bit and stop that then immediately cuts conically into the plastic. Once I remembered that my drill press had a stop built in, I got perfectly clean holes every time.

I drilled all holes for the project a little shallow first, then tested with a magnet as I slightly drilled more each time, up to the stop value I set in, until the magnet was just a hair's width lower than the surface of the cubes. As the cubes aren't all exact, I couldn't just rely on the stop itself.

The trick is to not let the magnets touch. In that last hair's width, their force becomes tremendous, and it's much harder to shear them apart. Better to let them be lower than the surface, and have only the acrylic surfaces slide against each other.

The magnets themselves slid in to an almost air-tight seal. Their slippery nickel-plating helped a lot here. To get the magnet back out after I tested it, I simply pushed the block up against part of the drill press, and it fly out and stick to the metal. In this way, I could keep drilling just a bit more and dropping the magnet back in to test for the right depth. Many times, however, the holes were the perfect depth after the first drilling.

Step 7: Glue in the magnets

Without prior testing, I settled on Duco Cement from my local hardware store. You can see in the first two images that I'd put a bit of the glue in the hole, then push the rod of magnets into it, and slide the rod sideways to leave the tip magnet in the hole - always remembering to check the polarity.

In the third image, you'll see an interesting phenomenon of my materials choices. Duco Cement eats through faults in acrylic. As such, the circle at the end of the bored shaft, where it meets the crown, would "bloom" outward at a roughly 45 degree angle cone. Quite pretty, though not what I intended. Some of these blooms got pretty complex and wavy, but most just appeared like the conical cloud of vapor that trails supersonic jets. As the glue rehardened each time, the structural integrity of the cubes was not compromised. If I make another cube, I'm going to test other glues to find a nice clear one that doesn't do this, but still has this kind of strength and fast-drying time (30 seconds or so). It remains an interesting thing to see, however.

Be sure the 6 magnets you glue into the central piece have matching outward-facing polarities.

Step 8: Drill and fill the 6 center face pieces

These are the pieces that attach to the 6 faces of the central 'axle' piece. They require all but one side to be drilled and filled with a magnet. These untouched sides will be the center facelets on each of the 6 faces of the cube.

Make sure you get the polarities such that these cubes will stick to the center cube!

Step 9: Drill and fill the 12 edge pieces

Now it starts to get fun. The edge pieces each join a pair of center face pieces, and eventually a pair of corners. This leaves 2 faces undrilled, and you just need to make sure these 2 faces connect along one edge.

Again, make sure your polarities work. The two sides that connect to edge pieces need to match - so both N or both S facing out, because a piece can get spun around and return flipped to the same position. Likewise, the corner-facing sides need to match outward-facing polarities, for the same reason. In my model, the edge piece facing sides are opposite in polarity to the corner piece facing sides. This is probably the best way, as I've found that my cube can combine very well in all manner of unexpected positions.

You'll note in the pics that you can now make a central 3x3 layer with 1 central piece, 4 center face pieces, and 4 edge pieces. You can also remove the central piece - something you can't do with a regular Rubik's Cube. Too, you can create the whole cube now, sans corner pieces.

The last pic shows the flexible nature of the layers of the magnetic cube. It's fun to twist it back and forth like taffy.

Step 10: Drill and fill the 8 corner pieces

The corner pieces have 3 sides that face out, and shouldn't be drilled, and that means they have 3 sides that should. Just be sure they're all connected at one corner, and that your outward facing polarities all match, and mate properly with the edge pieces.

Step 12: Optional step - labels!

My newly-acquired cubing habit has not only spawned a bunch of weird project ideas like this, but has also seen me gather lots of official cube junk to me, and as such, I have a stack of nice PVC labels (the polypropylene are crap - steer clear of these immediately-peeling nightmares).

Many people, including me, prefer the beauty of the clear cube, but as this one is my first, and kind of homebrew looking, and because it got boring having nothing to solve, I applied some official labels and made it a real cube, albeit satisfyingly heavier. You really feel you could do some damage throwing this little cannon ball.

The only thing to note here, besides making sure you center them carefully, is that if you want it to be official, you need to put orange opposite red, green across from blue, and yellow on the flip side of white. Also, you need to get the winding order correct. For example, if white faces up (and thus yellow down), and blue faces you (and thus green away), then red needs to be the left face, and orange the right.

Enjoy your new cube, labeled or not, and remember that if you want to apply imagery to the faces of the cube, the edges and corners will always work out again when you solve it, but the centers can end up in 1 of 4 rotations, which greatly increases the number of possible solutions, and makes solving it by traditional methods all kinds of way harder. You can use that to your advantage in a cube with a pattern that can have its subcomponents twist without getting messed up.

Luckily, the magnetocube is easy to take apart and put back together, either way :)
1-40 of 237Next »
NESmodder1 year ago
Very nice!
tap guy5 years ago
For a totally different look, make your own cubes from scratch with clear liquid resin. Add dye, pigment, embedments or swirled colors. The cubes could be cast with magnet hole already made. No drilling! Check out our video "How to make jewels, gems, crystals and pendants" on youtube or tapplastics.com
In the mid 90's I was really into resin casting. I would use molds and resin from Tap and rare earth magnets from Black Feather electronics. I would make interesting designs such as sea scenes with fish stickers and plastic plants from craft stores, as well as sand. I would tint the first few layers with blue dye and then the final layer with blue opaque pigment and the magnet, and maybe a thin layer with surface curing agent to prevent it from being sticky. Also I liked making domes with an artificial rose in a thick clear layer with a white opaque layer and felt behind it. I always wished I had a hood fan though lol!
In the mid 90's I was being born.
majorson2 years ago
Great instructable! If you interested in Rubik's Cube 
Than Visit my Rubik's Cube solution easy Website:

Rubik's Cube 

Foaly74 years ago
Could you spray paint the sides? And if so, is there any paint that would make it translucent instead of transparent?
Just use a matte spray paint.
Fabritren4 years ago
Hello" nice tutorial, by the way, is it possible to build a 2x2x2 cube using this method? I'm interested in building it, so, just want to be sure if it will work fine...
Thanks!
Sure it will. You just need to make sure it is a cube and you will need to rearrange the magnets and holes
reddevved3 years ago
About the sticker placement I think Asian cubes are the opposites on yours are adjacent (hope that makes sense) but I don't know what colors are opposite.
jj.inc3 years ago
Drop it, then just put it back together the semi-easier way
The force magnets exert on each other is explained by the inverse square law. Say you have 2 magnets (with opposite poles facing each other) 2mm apart. Now you move then to 1mm. You just halved the distance so the inverse square law says the force will be four times as powerful! Inverse square law works like this:invert the fraction that the current distance is of the original distance and then multiply it by itself. 1/2 inverted =2/1 2/1 (two) times 2/1 = 4
That is not entirely accurate. That would only be true if the magnets in question were magnetic monopolies (meaning one was entirely north and one was entirely south). Although nothing in Maxwell's equations forbids these from existing (on the contrary, if they did exist it would explain charge quantization) none have ever been seen. The magnets we deal with in every day life are rather more complicated. In the far field (so on a length scale much larger than that of the magnet) they usually approximate a dipole field, which obeys an inverse cube law. In the near field It depends on the shape of the magnet and the way that the magnetization is distributed within the magnet. It is probably best to deal with this as a multi pole expansion that can be truncated to whatever accuracy you like.
Zazou adastria5 years ago
del B = 0 forbids magnetic monopoles. You need to rewrite Maxwell's equations somewhat to allow for them.
do i remember an episode of big bang theory in which sheldon discovers a way to make monopoles possible?
adastria Zazou5 years ago
Clearly.
Look, physical laws are descriptive, not prescriptive. The only reason that magnetic fields have zero divergence (<nabla,B>=0...remember inner product. as you state it you are taking the gradient not the divergence) is that monopoles have not yet been observed. Obviously, Maxwell's equations could be modified to include magnetic charge. As is they just have that charge set to zero.
Zazou adastria5 years ago
Apologies--should have been div rather than del. Of course physical laws are descriptive, but by what you've said, you may as well say "nothing about the laws of thermodynamics forbids free energy devices". The presumption behind such a comment is that the mentioned law is an accurate model of the physical universe, otherwise you're just talking in tautologies.
ahhh! my uncontrollable cubing habit is driving my up the wall of awesome!! my record (that i actually timed) is 01:27.52. i might have done better with out timing, not sure though..... this is an AMAZING instructable by the way. i realllllly want to do this, but i dont have a drill press.... dang!!
get your own cube, already made: magneticcube.com
try a vice and a power drill (will take a few tries as you need to be dead center all the way through)
22killzz4 years ago
about how much was the total cost?
prodo1234 years ago
You know what would be cool? a transparent sticker on that cube. It has the Rubik's Cube feel while retaining the clear glassy feel.
How much money does it cost to get all those magnets?
$22+S&H
rjt1709774 years ago
Love it
How much did it cost in the end stickers and all?
ubercurious4 years ago
 hmmm, rather than stickers, I wonder if you could dye the cubes for the colors.  It would look much nicer and stick with the clear theme.
LocTite makes a UV cured adhesive that cures with the help of a special UV light it's practically invisible. Although for home use I think a glob of super glue should do the trick. Anyway really cool Rubiks Cube.
arhodes185 years ago
very cool! So you can't solve this by using the traditional patterns though? that kind of stinks... fave'd +5
JellyWoo5 years ago
Cool! A good place to find stickers is http://cubesmith.com/.
manman33308 years ago
How do you get Maya?
You don't. Use blender, which is an open source program that matches, and at times exceeds, the functionality. www.blender.org
Or don't. Blender is marginally more confusing than a book in a language you've never even heard of.
But it's free And there are tons of excellent tutorials on Blender. I would reccomend youtube username Super3Boy; that's how I learned
Blender really is awesome, and it does exceed maya at times. Although, it is very confusing at first, once you become accustomed to the controls, you find it is very quick and streamlined to use. I think blender will be easier for newbies to understand once 2.5 is out (no offence to anyone).
gfixler (author)  manman33308 years ago
You can buy it from www.autodesk.com, or try out their PLE (Personal Learning Edition - free trial), also from the site, or steal it somehow, say through bittorrent. It all depends on how much money and integrity you have. I have it because we use it (registered copies) at work.
I beleve that the PLE has no time limit, as long as you use it for only personal needs.
yeah, it just puts a watermark in the file and has a seperate file format.
bumper445 years ago
My record for solving is 1:41. Here is a video of me solving a Rubiks cube!

That's pretty good. Although, I think a friend of mine can do a 5 by 5 in a little under 2:30.
1-40 of 237Next »