I was inspired by this site.
Some details:
- wire is 3mm thick
- screws are M6 copper. Could also be stainless steel, but that is difficult to solder !
at one end one bold, at the other 3 bolds. 2 are soldered to the copper plate of the box. Do that with a stainless steel screw in it
to avoid soldering the screw! Put a third bold on the copper screw and turn the screw as far as necessary for the filter tuning.
The third bold can be used to fix the screw after tuning.
- I fixed the top of the coils with a piece of PCB material. Two wholes of 3mm in it, remove most of the copper and solder it to the side of the box to fix it, I used fast glue.