So this is my Open Master Pentultimate. It was obviously inspired by the open puzzles of Tony Fisher. However, having the freedom of 3D printing I am not limited by existing puzzles. Tony's Open Petaminx for instance has a Megaminx on the 'inside' but having it there does not really add anything since the Megaminx is also on the outside. My version is a bit like a Multidodecahedron, with a (bandaged) Megaminx on the inside and a (bandaged) Master Pentultimate on the outside. This means the outside can be solved while the inside is still scrambled or vice-versa.
A mayor advantage over my Multidodecahedron is that it is far much easier to see inside.
This puzzle only really has 3 turnable faces. This was achieved by removing the cuts surrounding one corner. An alternative would have been to remove the 5 cuts surrounding a center, which would have essentially resulted in a Pentultimate (with internal parts visible). I decided to stick some gold stickers on the open part since without them it just looked very dark. I think this is nicer.
The puzzle is 40mm on an edge. It's quite large so the puzzle on the inside is also nice and large. The hole is about 60mm in diameter.
The rotational movement on this puzzle is very smooth. I have not used springs in this design as that would have required the inner puzzle to become smaller which would have been a shame. The feeling of this puzzle is therefor a little different from other puzzles which do use springs like my Multidodecahedron but it's still very good.
If you order this model, you will get a DIY kit of the plastic parts needed to make this puzzle. You will need to supply your own screws (M3), stickers and springs for assembly.
You can also order an assembled copy of this puzzle from me directly, but this option is more expensive and it will take longer to get your puzzle.
Shapeways has recently changed their pricing making this model much more expensive. I've not yet had the time to optimize this model to be as cheap as posible. Please contact me at firstname.lastname@example.org if you are interested in obtaining this puzzle so we can discuss cheaper options.