The wing posts are the next things we will need to make. The tissue tubes which you created are 3/32" diameter so we need our wingposts to be the same diameter so they will plug into the tissue tubes. The wingposts are made from very hard (10 to 12 pound density) 3/32" square balsa. The wood needs to be hard because the wing is attached to the model with these two posts, and they can be subjected to a lot of loads when the model is flying around. Cut two pieces of the wood 4" long.

Note: The plan states that 1/16" x 1/16" basswood may be substituted for the 3/32" square balsawood in this step, but it will require 1/16" diameter tissue tubes to be rolled instead of the 3/32" tissue tubes rolled.

What we want to do is turn this square piece of wood into a round piece of wood that is just the right size to slide into the tissue tube snugly. To do this, use the sanding block to sand off the corners of the wood to round it. Continue this process of rounding and sanding the wood. Periodically, check to see if the wingpost will slide into the tissue tube. The fit needs to be snug, otherwise the wingpost may come out of the tube during flying and can break the model. If you overdue it and sand too much off, then just start again with a new piece of 1/8" square.

Here is a rounded wingpost with a snug fitting tissue tube.

A completed set of wingposts and sockets.