Marked the two left side spar mount angles for the height of the flap detent. Put the forward and aft detent mount brackets in place with cleco clamps, and cleco-clamped the detent angle to them. Noticed that maybe these mount brackets shouldn't be exactly 90 degrees since the two spar angles are parallel, but the detent angle isn't exactly perpendicular to them. So the forward angle should be slightly greater than 90, the aft one slightly less. Tried 4 degrees to start (since that's what the spar angles are bent to), but it turned out to be about half that. Finally got the detent angle to sit at the right height off the fuselage side wall at the forward end (the reference dimension given). After getting the detent angle to sit well, I removed the aft spar attach angle with the mount angle clamped to it, marked the hole pattern and drilled both of these parts, plus the trim cable retention bracket on the drill press. Riveted these parts together. Needed to use a little spacer at the tip of the rivet puller to get down into the channel between the spar mount angle and the trim cable retention bracket, but the rivets all pulled nice. Clecoed it all back in place. The forward mount bracket has to be drilled in place, since the forward spar attach angle is already riveted to the fuselage side.
Flap detent angle in position.
Rivets on aft side needed spacer on riveter to pull.
Trying to show the mount angles aren't exactly 90 degrees.
