Brief Description: Drill front section of Center Spar for 3/16" Rivet
Drill front section of Center Spar for 3/16" Rivets
1. Mark the center line of the Center Spar Webs on the top and bottom on the front side of the front half and the aft side of the rear half. 2. Mark the center of the Top Doubler on the vertical flange. Set the Top Doubler on the front half of the Center Spar. Align the center line marks and clamp the Top Doubler to the Web. 3. Back drill 5/32" through the Web into the doubler, clecoing. 4. Mark the center of the front bottom angle on the vertical flange. Set the Top Doubler on the front half of the Center Spar. Align the center line marks and clamp the front bottom angle to the Web. 5. Back drill 5/32" through the Web into the front bottom angle, clecoing. 6. Cleco the top and bottom spar caps to the web and doubler. 7. As noted on 2/17, I enlarged the holes on the front section when I removed the solid rivets. So, drill #11 through the rivet holes in the top spar cap to enlarge holes for 3/16" rivets. Cleco as the holes were drilled. The drilling was done on the drill press with the piece supported with the drill press table and and a roller stand. As shown in Figs. 1 & 2, I used a level to make sure the spar was level. 8. Use a transfer punch to mark the centers of the 5/16" bolt holes for the wing attach bolts.