Simple Fidget Infinity Cube
I recently purchased a wood etcher and wanted something worthwhile to burn pictures onto. So I decided to go with a fidget infinity cube. I had to take 2 runs at it cause I made some mistakes on the first go around. The main difficulty is leaving space for the hinge and keeping the hinge aligned for easier bending. So here's what I built.
Supplies
Mark Where You Want Hinges to Go
First off there are 8 hinges needed for this project. And for me, the three-dimensional geometry can get a bit muddled when you're trying to remember which hinge goes where so I suggest marking the spots for all 8 hinges with a corresponding number. The above is the numbering scheme I used and will be referring to (hinge 1, 2, ... 8) in this project, but you can use whatever numbers or symbols you might like. Make sure to make the numbers small so they will be covered by the hinge.
So lay your cubes in a 2 x 4 setup and put 1s, 2s, 3s and 4s on the top as pictured. 7s and 8s go on the sides. and on the reverse goes 5s and 6s.
Attach 2 Blocks by a Hinge
Bend one hinge over the edge of the cube so that both sides of the hinge are fully flat on each side. Then place the clamp on the side that did not have the number on it. Make sure this clamp is firmly pressing against the hinge's leaf and not its knuckles or pin. Also, make sure the hinge is centred, it doesn't need to be perfect but should look good.
Using the Drill drill 2 holes in the centre of the holes on the leaf. It will help to go slowly at first then build up speed on the drill once you're sure of the positioning. If the holes are where you want them then screw the screws into place. If not see below on what to do if holes are in the wrong place.
Next lay the block flat with the hinge at the top and folded together. Then use 2 spare hinges placing them with knuckles at the edges of the square and the side with the attached hinge between them (see picture 3). Then place (carefully) the other block with a 1 on it on top of that cube and press them together with a clamp. This part is finicky and may take a few tries. Keep the faith and I'm sure it will work out. Apply another clamp to either side of the 2 cubes to keep them aligned.
Make sure the cubes are spaced out, by the spare hinges, and that are completely aligned in all directions. Then fold the exposed hinge over and drill 2 more holes, carefully. If the holes are where you want them then screw them into place.
Repeat this step three more times for the sets of cubes for 2, 3 and 4.
What to do if you make a mistake positioning the holes
If you accidentally drill a hole in the wrong place and it affects the alignment of the hinge then fill that wit would glue, and maybe some sawdust if you have some. Then let it dry and try again Mae sure the drill bit is exactly where you want it and try again. If you have to do this more than once i'd use a new block.
Attach Hinges 5 and 6
Now that you have 4 sets of attached cubes it's time to attach sets 1 and 2 via hinge 5 and blocks 3 and 4 via hinge 6.
Similar to the last step take the cubes with 1s on them and bend a hinge over the corner that has a 5 on it. Then clamp it in place on the leaf, avoiding the knuckles of the hinge. Drill the holes on that leaf and screw it into place. Use 2 or 4 hinges as spacers again by lying them on the block. I only used 2 but if you can get them to balance on the other cube it might make a better spacer overall. Then clamp the set of blocks with 2s on them on top so that the 5 on that block lines up with the hinge. Clamp it into place and make sure all sides line up again. Drill and screw it into place.
Repeat this step for the blocks with 3s and 4s on them joined at the sides with the sixes on them.
Joining All 8 Blocks.
Starting with the cubes with the 7s on them (for numerical purposes only) bend a hinge over one of the cubes with a 7 on it. Clamp it in place, drill it and screw it in place. Do the same for the block with the 8 on it that is connected to the block you just attached a hinge to. See pic 3.
Lay the blocks flat (as in pic 3) then fold the blocks up so hinges 5 and 6 are now on top put spacers between hinges for blocs with 7s and 8s. This part requires you to have 5 or 6 hands (kidding), but seriously it's hard so may take a bit of time but once you get it press the blocks together and clamp them. Make sure EVERYTHING is lined up in all directions. Drill, Screw, breath cause you just finished all the hard parts.
Finishing Off Your Blocks
So you can sand down the edges if you like. I chose not to on this one but you can if you like. I did choose to add 3 coats of polyurethane (varnish) to each side. which I recommend doing 1 side at a time. Polyurethane takes a very short time to dry. Make sure you lightly sand with a fine grain sandpaper between 2 layers 1 and 2 (and 3 if needed). All in all, it took me 2 hours to do this but only about 10 minutes of effort and really increases the niceness of it.