This model prints in place with built in hinge and clasp. This should accommodate any soldering tips with dimensions under 6.6mm for the diameter and 66.4mm in length. I modeled this with the Weller ST series soldering iron tips in mind.

This should also be able to store CNCKITCHEN's threaded insert adapters for soldering irons.

I would recommend printing it at 0.2mm layer height or less for hinge to work properly.

No supports needed.

V2: larger size detent to catch the lid properly

I have a “wider tips” version to accommodate tips up to 7.2mm in diameter. 

Please let me know if you like to see other cases made specifically for your soldering iron.