Marked rivet lines on elevator skin 8.5mm from top and bottom edges of trim tab cutout. Marked matching lines on the cutout channel. Layed out holes at 40mm pitch on bottom skin and pilot drilled. Ensured line drawn on channel flange was centered under skin pilot holes and web of channel was flush with skin edges then match drilled bottom flange of channel.
Used trim tab as marking template to lay out the holes on the top skin, punched and pilot drilled. Again ensuring marked line was centered on skin holes and channel web was flush with top skin I match drilled top flange of channel.
With hinge attached to trim tab I inserted opposite hinge flange between skin and channel. Created equal gaps at each end and held trailing edge of tab co-linear with elevator trailing edge. Match drilled a hole at each end to hold hinge in place then drilled matching dimples in remaining hinge hole locations. Removed hinge to through-drill the pilot holes. This two-step drilling method ensured that any misalignment of the channel holes would not result in elongating those holes when drilling the hinge. Concluded todays work by finish drilling all holes up to 1/8".
