6 holes on each side need a spacer to prevent the skin bulging inwards and preventing unnecessary stress on the underlying flanges.
This illustrates the gaps between the skin and the flanges:
To prevent multiple spacers I designed one single spacer with multiple thicknesses and a required taper:
CAM was quite some work because it requires 2 operations (front and back) so a soft jaw was needed to be machined as well.
From stock 6061-T6 the parts were machined:
Test fit of the part:
Inside view with the skin attached:
Final check to confirm that the skin is flush now:
