May 27, 2008 ...  When I built my work table I took special care to assure that the surface was perfectly flat and the front edge was straight. That has proven to be very helpful .Using the straight edge of the table as a guide, I attached (screwed) a piece of smooth, flat Melamine trim to the tabletop.  To straighten out the traditional Sonex warp that occurs in the Main spar from the riveting process, I clamped the left wing rear spar so that the spar edge followed the trim edge. I then shimmed up the wing airframe so that it was perfectly level with the table.

 

Then came the great moment of truth ...I laid the wing skin on the airframe, and checked out the fit. Yeehaw! It fit absolutely PERFECT!  It looked so good I went ahead and pre-drilled and clecoed the skin to the rear spar and used spring clamps to hold the skin to the forward edge to the main spar. This is one of those jubilant moments when I realized the worth of the Sonex kit. I don't know that everything would have lined up this perfectly if I had to layout, cut and pre-drill the wing skin myself, or fabricate the ribs from scratch.

 

I set up my workstands and leveled them with my digital level. Then I had my son help me lift the whole wing assembly and set it on it's main spar. I used some 1/4 inch steel rod and 3/4 X 1/8 inch flat aluminum bar material to fabricate a couple plumb bobs. I put a 1/4 inch hole (centered) on one end and put a centered point on the other end. I put a plumb at each end of the wing by sliding the rod into the rear reference  (production) holes on the ribs and suspending the aluminum bar. It didn't  take much shimming to level up the wing. After both plumbing rods centered on the forward production holes, I made a final check with my digital level and clamped the spar to the work stands. I am finally able to pre-drill. I followed the Sonex technique of starting with the center rib and fanning outward.