Demon Core Pen Holder

The Demon Core Pen Holder

A pen holder modeled after the demon core. Putting a pen in the holder will cause the lid to be lifted up and away from the base, exposing the core. Once the pen is removed, the lid will drop back down and fully surround the core. If this were to happen with the actual demon core a criticality incident would occur, but this one is just plastic so you're safe! This idea had been floating around in my head for a few months, and when I saw the Prusa blog post about their new radiation shielding filament I decided it was time to sit down and actually design it. Enjoy!

Can also be used to hold screwdrivers.

File descriptions

Files with three different pen hole diameters are provided, 9mm, 13mm, and 20mm. The 9mm pen holder will hold objects the size of wooden pencils or bic ballpoint pens, the 13mm will hold objects the size of sharpies or some fountain pens, and the 20mm will hold large whiteboard markers. Each size has two variations, one for single color prints and one for multi-color prints. The multi-color file has individual entities for the top, bottom, legs, and core, as seen in the render. 

Print settings

This model is print in place, but will require some supports on the legs and hinge. I used the following settings:

• 0.4mm nozzle
• 0.45mm line width
• 0.2mm layer height
• 10% gyroid infill
• Organic supports, smart fill brush used to apply supports to the legs, top and bottom shells, and the hinge

Additional parts needed

You could add four rubber feet to the base of the legs to keep the pen holder from sliding around, but they aren't necessary.

Colophon

All parts were designed using onshape and are fully parametric. If you want to make any alterations to the design, it is accessible here.