Instead of using threads to fasten the egg together, this model uses magnets! This makes it easier to align the colors of the top and bottom when using multi-color filaments and is so satisfying to open and close!
All you need are magnets that are 6mm x 3mm. You may need to glue them in. I designed it to be a "loose press fit" for the magnets, which means, depending on your printer's configuration, it could be fine being press fit in, but if your printer is extremely precise, you'll probably need to glue them in. Just make sure the magnets are oriented properly so you don't get them repelling each other.
It's recommended that your printer be well tuned to ensure pieces fit comfortably. Tolerances are set to 0.3mm. This puts the fitment somewhere between snug and loose in order to accommodate the wide variety of printers out there and their tuned states.
If you happen to have clearance issues, you can always scale the model up in order to loosen up the tolerances necessary for pieces to fit together properly.
Happy printing!