Drilled bottom skin for about 1 hour. Rotated the bottom skin + sides upright and set on the work table. Aligned 3 aft cross members to start squaring up the assembly, about 1 hour. Spent about 1/2 hour trimming F24-01 box cross beam by 3/32" each side (only where it interfered with the 3/16" joint plates). I added up the dimensions and remeasured the box beam, and the box beam length plus a 3/16" plate each side plus the 2 .032" skins should add up to exactly 40", but it was giving me 40 3/16". After trimming, it pulled into 40" right on. Spent the remaining 1/2 hour or so aligning the forward box beam to each side to give 40" width at bottom and top of the fuselage plus squareness. Had to rig a string to pull from the lower left (access hole in the vertical member) to the upper right (a cleco in the 3/16 splice plate). I couldn't very well gently press this into position by hand, but using the string, I could pull it a little at a time. Drilled the 4 corners of this assembly to maintain the squareness.
