1. Position gusset so as to catch existing rivet holes, and align with side of fuselage. 2. Back drill existing #40 holes and cleco. 3. Back drill existing #20 holes from bottom of fuselage. 4. Back drill side holes with #40 bit. 5. Remove gusset, and mark position of extra rivets on bottom of gusset. 6. Punch and drill with #40 bit. 7. Reinstall gusset. 8. Back drill #40 holes just added. 9. Open #40 holes from bottom with #20 bit for A5 rivets.
