Delete clipping part of 2 objects?

[oort]

Florens,
You can also create a hole without adding the booleans plugin.

See how to create a circular shape on a square face in the "Forming a circular face onto a square, using inflate" section here... circular face

Then you can select newly created circular faces on both sides of the cube and use the "Bridge" command to cut the hole.

(To see how bridge works... Create a cylinder > In face mode select both ends > Inset both ends > Bridge.)

Maybe more work but it works...

There is lots of useful info in the ppzpitstop by Puzzledpaul. Puzzledpaul Tutorials

oort