Hey, so I had a big model that I cut down and didn't want to use glue, I have searched the internet but didn't find any lock or something that can help me to hold both parts together without glue , so I designed a simple lock that you can drag and put inside your cutted model , and then connect them without any glue :) , super easy to install and super easy to deatch if needed.
 

Fell free to resize to your needs!(Resize all the 3 parts together)

Basically the round shape is bigger than the enterance , that why it needed to bend a little and when it gets in it will just be stuck there untill you put force.

Simply drag the box to your first half cutted model and put it inside , but so the hole be visible , do the same to the second part.(Make sure they are aligned in the same line , so it will seat straight.