Hi Andre,

Here's a (mostly) repaired version that booleans with the rectangle ok.

The problem was that there were some really tiny edges and surfaces. Some of this junk was along the edge of the rectangle and so was confusing the boolean. I found the problems using this plugin:

https://moi3d.com/forum/lmessages.php?webtag=MOI&msg=11271.13

I then separated out the bad surfaces, trimmed off the junk, entirely remade the large cylindrical surfaces, and then joined everything back together. I left in some junk outside the area of the boolean. One problem is marked with a red point.

- Peer