This is a T12 tip holder I designed for my portable soldering station.  There is a cavity in the “Holder Bottom” file to encapsulate a 30mm x 2mm magnet.  The idea was it would prevent the holder from falling over when selecting a tip.  However, I have not tried this feature.  The lid should be a tight snap fit with little to no back and fourth movement.  

This T12 tip holder is small enough to easily fit inside a Harbor Freight Apache 1800 case.  This was one of my requirements because this is for my portable soldering station.

To add the magnet insert a gcode pause on layer 15 and insert the magnet.   Please verify the dimensions of the magnet vs the 3mf file.  I have found significant size differences when re-ordering magnets from Amazon.