Magnetic 4 Cavity 21700 Case

Purpose:

This is a case I designed to hold extra 21700 cells for my flashlight (TS21) while not in use. I needed some way to safely carry them around without losing them. This case will electrically and thermally insulate the cells to keep them from shorting out and keep them from getting too hot or cold. I have designed it with a minimum wall thickness of 2.5 millimeters, while conserving plastic and being easy to print.

Printability:

There is a small section of overhang on the bottom of the case which can easily be bridged by most printers. No support material was required for me.

Most 3D printing plastics and settings will work for this design. I made mine in ABS, with a 0.2 layer height, 4 outside perimeters, and 40 percent volumetric infill.

Assembly:

Print (2) of the identical case halves, provided in .STL format, or .STEP file for customization.

Gently press (10) small 3mm cubic magnets into the square pockets in each half of the case, using glue if needed. The fit of the magnets will depend on how accurate your printer is, I used a dab of super glue on each magnet.

(Make sure that the polarity of all the magnets in one half is facing the same direction and insert all the magnets in the other half facing the opposite way so that the halves don't repel each other.)

Dimensions and Compatibility:

The rough external dimensions of the completed case are 105mm x 76mm x 24mm (4.125in x 3in x 0.95in)

This case is designed to fit flat top 21700s and it was designed to support the Samsung INR21700-50E (21.1mm x 70.6mm) and the Wurkkos 21700 (21.2mm x 71mm) including a small amount of outside clearance for both.