Clamped & drilled main ribs 1-5 to rear spar. Used 9/64" bit for pilot holes, thinking that 3/16 bolts went there. Drilled one hole up to 3/16" size. Did not double-check plans! Holes can be enlarged to accomodate AN426-5 rivets. 3/16" hole can be enlarged to -6 rivet size. Drilled 3/32" pilot holes in center of ribs 1 & 2, then drilled up to proper size of #30 bit. Drilled 3/16" hole in doubler for these 2 holes.
