Im all new to this, so let me know if any information is missing.

My problem wich ended with this project: I bought an old tabel and some old chairs, but the chairs couldet go under the table.

I designed a circel in TinkerCad with a diameter on 58mm wide and 15mm in height. On top og that i made a circle with a hole in the same diameter of 58mm and set the wall for 1 which made it 3mm wide, so it wont brake off, so the hole is 55mm wide. I made the wall 10mm high, so the extender works like a cork and you dont need any screws.

Dimensions:

Bottom 58mm wide x 15mm high

Top 58mm wide x 3mm wall x 10mm high

You can modify the model for fitting your table leg. Measure the diameter and fit the model to it.

I attached a file from TinkerCad and the file from Cura. Guess Cura saves the settings from my printet setup.

Hope someone can use this.