You're looking at a close-up of the elevator. I installed a hard point which is in this case is a 5/16" hardwood dowel. I don't see this done enough on planes that I see being built. The purpose of the hard point is to stop the balsa from being crushed when the control horn is tightened down. Not only does it weaken the balsa, but it can change the angle of the horn effecting the geometry.