About this 3D model
Just print it, let it cool down and try to take out the middle part. Print-Settings: 2 Perimeters and minimum 5% Infill → If you want more, go higher. If you like you can try out my other difficulties of Tolerance Tests here: https://makerworld.com/en/u/3276628277 I bet you can't get them all to work !!! 0.05mm → Difficulty: Ultra Hard 0.1mm → Difficulty: Very Hard 0.15mm → Difficulty: Hard 0.2mm → Difficulty: Normal 0.25mm → Difficulty: Easy 0.3mm → Difficulty: Very Easy