Brief Description: Z Brackets - drilling to left spar
I drilled all the left wing brackets to the spar.
First I double checked the alignment of all brackets and clamped the bracket about to be drilled. Rechecked alignment after clamping as the bracket sometimes budged slightly during clamping. I clamped the bracket in such a way that I could back-drill both remaining holes (using the spar as a guide) without needing to remove the clamp - this minimised any opportuniy for later mis-alignment.
Usng both a set square and the centerline alignment from the bottom of the spar to ensure a square fit
Bracket clamped into position once aligned - double check alignment after clamping
Try to clamp in such a way that you can drill both holes without removing the clamp