I worked on the cabin frame today. Drilling the inner straps to the channels had to be very precise. I did the aft channels first. The lower inner strap was clamped and drilled from the center toward the ends. The strap tries to bent up out of the channel in the curve, so many clamps were neede to keep it in place. Once the two inner straps were drilled and clecoed in place, I make 6 blocks 1-3/8" thick. I used these as spacers between the aft channels and the forward channels. I put the forward channels over the spacers and clamped them in place. The frame is 1.5" thick, so the spacers allowed for the 1/16" thick channels (2x). I used my angle drill for all of the holes. Once the parts were assembled, I drilled the F-631E plate and clecoed it in place. The next step was to set the whole assembly up on its ends and measure the height. It needs to be 17-19/32, but mine was about 17-21/32, so I used the belt sander to shave off enought to make the measurement perfect. I didn't take a picture of the completed assembly, before I broke it down for deburring and countersinking. There are about 180 holes to deburr and countersink in this thing.....I did that for another hour before I called it a night......
The lower inner strap is drilled to the channels.
The lower strap is on and the upper strap is ready to drill.
