Important ! All flanges of all coax busses (the 12V power connector too) MUST make good electrical contact with the OUTSIDE of the housings.

Drilling holes for the N-flange-busses :

-  Use a column-drilling machine and machine vice.
-  As the cabinet sides taper, punch the center of the holes and pre-drill with 2mm.
-  First drill de big hole.
-  Remove sharp edges.
-  Drill four 2,4mm holes for the M3 screws.
-  Remove sharp edges.
-  Tap the four holes in the housing with M3 thread.

By tapping the holes into the housings, and fixing the N-busses with screws from the outside to the inside, these screws will make at first contact with the outside of the cabinet.
You do not need to remove any paint from the boxes, although it does not harm.

     Watertight and oxidation free installation :
-  Apply a little acid-free vaseline (petroleum jelly) between the N-flange and the cabinet, onto the screws M3 thread, into the M3 holes, and onto the thread of the N=bus. -  Install the N-bus using stainless steel M3 screws.
-  Lock the screws by nuts at the inside of the cabinet.
-  Wipe-off all external  vaseline.

Rem :  when connecting the N-plugs, apply also vaseline onto their thread, and to all contact surfaces.

When closing the amplifier cabinet, apply vaseline onto the cabinet packing ring, its groove and the thread of the lid-screws.