I can't finish up the assembly of the center section until my stainless foil tape arrives but I was able to match drill and fit the spar spacers this morning. I began by inserting the spacers between the spar bars attached to the fore and aft center section bulkheads and lining them up flush on the bottom and top.
Next step was to mark the spacers for drilling using the holes in the center section bulkheads. You don't want to use the spar bars as a drilling guide so I used a transfer punch to mark the locations on the spacer for each 1/4" bolt hole. I bought a set of transfer punches form Harbor Freight a couple years ago knowing they would be of use someday and today was the day. I selected one size smaller than 1/4" because the spar holes are so tight.
After leveling the work surface on my drill press, the four holes were drilled in each spacer. The holes were drilled with a bit measuring .280 rather than .250. This makes it easier to insert the close tolerance bolts through the assembly. By the way, when working on rather precise components like the center section spar spacers, a plumb and true work surface on the press is critical.
