Machined up a drill guide to suit a 3/16 drill bit. Leveled the extrusion .020" above the spar caps and backdrilled through the spar caps into the extrusion.
If you are having trouble finding a .020" shim to shim the extrusion above the spar caps, the brown metal strapping used to strap bundles of timber together at Aussie hardware shops, is exactly .020".
Drilling, really is boring aint it
backdrilling with my drill guides keeps everything true
