Back to work! 7/45.5

It's been a while since I looked at the bones of my horizontal stab. So long, in fact, that when I tiptoed the trail around the left wing and nose of Cruella, who takes up most of the garage, I walked through cobwebs... EEWW. It was just one of those weeks where work was long and I kept forgetting to buy a new bandsaw blade.... cold beer & TV won the war most evenings.

Today I finished making the elevator hinge brackets. FINALLY. New bandsaw blade is WONDERFUL, like a hot spoon through ice cream. Also riveted HS-309, the center bracket pair, together with their sandwiched bearing. Drilling that proved to be more of a challenge than I expected. The center hole was pretty easy-- I drilled a 1/8" hole in the center, then enlarged it to 3/4" using 2 different Uni-Bits. I did not know how easy it is to move a hole one way or the other with a uni-bit... my pilot holes were perfectly aligned with each other, but by the time the big hole was finished, they were off by 1/32". It was annoying, but not enough of an error to cause any problems. Then, after deburring the holes thoroughly, I slid the bearing in place, clamped it to one bracket with a Vise-Grip, and drilled the rivet holes by placing the piece on the edge of the drill press table, which was angled off to one side.

I think there should be an EAA SportAir workshop called "Creative Clamping & Drilling," because I need some work in that area. Ben helped out a little here. The flanges of the bracket assembly had to be clamped to a flat surface to assure their alignment and perfect fit with the spar surface, so traditional vertical drilling was tough to do. (although now that I think about it, I could have clamped them to a piece of angle instead of the workbench... oh well.) While I match drilled the second bracket to the bearing and the first bracket, I used a couple of rivets in the holes to make sure the bearing stayed aligned with the drilled bracket. (that was my idea.) Then, to make sure the brackets both sat flat, we clamped them to the solid work table with a long-reach welding clamp and used the long drill bit for the holes on the bottom that were too close to the table to reach with the drill and short bit. It was weird because I'm not used to drilling parallel to the ground, and I wanted to make sure the holes were drilled straight. To make sure I had the 12" bit parallel to the table, Ben showed me how to use your free hand as a gauge for drill bit height above the work surface. If I placed my hand so that the bit was just above the fingernail close to the work, then slid my hand back toward the drill and put the bit in the same relative height above the same fingernail, I knew the bit was parallel to the table. But then, as I applied pressure to the drill, it bowed the bit a little, so I have to watch out for that.

I figure by the time this plane is done, I will be able to teach "Creative Clamping and Drilling" myself.

Next, I laid out the brackets on the spar. I drilled a 1/16" pilot hole for the eventual AN3 bolt holes so that I could stretch a piece of string through there to get all of the brackets lined up along the spar centerline. This will assure a straight hinge line with no binding, if it all works as planned...