This giant tricky present has a hidden latch mechanism that will keep it securely closed until you twist the topper.
Printing
All parts can be printed without supports.
The base includes a few long bridging sections. If your printer struggles with printing straight bridges, pre-supported versions of each base are available. Just use a screwdriver and hammer to gently knock the custom support out after printing.
The spring works best if it's printed with enough perimeter lines to make the arms of the spring solid. This works better than just increasing the infill % because perimeter lines will flow in the direction of the spring arms.
Assembly
Assembly is the same as the original Twist Lock Trick Box. Watch this video for the complete process.
Make sure to pre-tension the spring by one gear tooth This will assure that the latches have a strong hold on the base. This is also necessary for the alignment of some toppers.
Make sure to glue the spring and topper If you do not fully secure these parts, the mechanism may become detached while in a locked state. I recommend using either super glue or 3D Gloop!, but hot glue can work as well.
Internal Dimensions Approximate internal space for each box.
This doesn't include extra space available in the corners and lid.
Base 38mm 180 x 180 x 38mm
Base 68mm 180 x 180 x 68mm
Base 98mm 180 x 180 x 98mm
Base 128mm 180 x 180 x 128mm
Base 158mm 180 x 180 x 158mm