2/12/2021 – 0.9 hours
The trim tab is attached to the elevator with a piano hinge that runs the length of the trim tab. The hinge was previously marked, and a pilot hole was drilled in the left end of each of the forward and aft halves of the hinge. The task now is to cleco the hinge to the rear spar of the elevator through the pilot hole, and then match drill the remainder of the hinge holes to the rear spar. The first key consideration is to ensure the hinge is aligned parallel to the spar. I did that by drawing a line 3/16” from the leading edge of the forward half to align with the hole I drilled earlier. I then clamped the hinge in place with the line showing through the center of the holes. I used 1/2" cleco clamps approximately 2 – 4 holes ahead of where I was drilling to hold the hinge tight to the spar, and cleco'd every hole after it was drilled to help keep everything straight and tight.
[#40 drill, 1/2" Cleco Clamps]
2/13/2021 – 1.1 hours
After drilling the forward half of the trim tab hinge, I used the edge of the inboard rib and the beveled edge of the rear spar to draw a straight cut line on the excess hinge material. I removed the hinge from the rear spar, did a rough cut with the Dremel metal cutting wheel, and finished the cut with a grinding wheel and finally the 6” cut-and-polish wheel. I rounded the cut corner, and deburred the trimmed edges. The entire process of drilling and trimming repeated with the aft half of the hinge attached to the trim tab spar. Pay close attention to the drawings in the plans to ensure the trim tab spar is oriented correctly and the hinge is attached to the correct flange. The other trick to the aft hinge drilling is to ensure the trim tab spar is clamped down adequately. I managed to clamp the bottom flange of the spar between the bench and a spare piece of wood.
[#40 Drill, 1/2" Cleco Clamps, Dremel, 1 1/2" Metal Cutting Wheel, 6” Grinding Wheel, 6” Cut-and-Polish Wheel]