I was looking to build a nutcracker for the upcoming season.
Quickly I decided for the screw type (less prone to "overcracking" the nut)
Target object should be walnuts.
I wanted the cup to be closed at one end in order to catch the finer debris an I also wanted to use a trapezoidal thread for the screw.
Since I was unable to find a proper design on Thingiverse I created one.
I opted for the "Hex" design style, maybe I will even print some spanners to use the cracker with in order for the cracker to be useable for my Kids.
If you plan to realize it in two colors I would recommend to actually print one set per color and the after you have broken in the threads mix the two.
just some minor grinding,sandpaper and breaking in the threads