This six piece puzzle is one of Stewart Coffin's classic designs! It's called the Cluster Buster because it's hard to even get it apart... but once you do then the real challenge begins because it's extremely difficult to get the pieces back together again due to the physical dexterity required to hold the pieces properly in the correct orientation. There are three versions of this puzzle: the original Cluster Buster has all six pieces with the same shape, however the "Improved Cluster Buster" has three different types of pieces which come in pairs. The Truncated Cluster Buster is essentially the same thing as the original one, however some of the pointy tips are squared off in order to make the puzzle itself more aesthetically pleasing for display and/or handling purposes.
If you want to make the original "Cluster Buster" then print out (6x) of the "CB piece finger finger" STL file.
If you want to make the "Truncated Cluster Buster" then print out (6x) of the "TCB piece" STL file.
If you want to make the "Improved Cluster Buster" then print out (2x) of each of the pieces EXCEPT FOR the "TCB piece" STL file
If you want geometrically precise pointy tips on the puzzle pieces then use the "sharp" folders but otherwise I recommend using the "snub" folders which should require much less post-processing cleanup work. The folders are also organized by the amount of surface offset applied, so start with the "minus-75" folders but if the puzzle fits too tight then go up to the "minus-100" folders. If the puzzle fits too loose then go down to the "minus-50" folders.