Sat Feb 2 2008

F-705 Rear spar bulkhead work

I was match drilling the #10 bolt holes for the seatbelt attach brackets and got these nice helical chips. I love a sharp drill bit. :-)

I drilled the bolt holes in the small spacer blocks, too. Note that I had to slightly increase the chamfer size on the spacer block for the left side.

Then I popped in a couple 5/8 inch holes for snap bushings.

Flipping forward a page or wto in the plans, I cut these bars to length. Why, you ask, did I jump forward? Well see that tiny little piece of leftover material in the upper left hand corner of the picture? I wanted to use that...

...for a spacer while I match drilled the other brackets to the F-705B doubler bar. That material is .187 thick, so I didn't have to fabricate a spacer.

Just clamp the puppy in place, flip it over, and drill through. Boelube was used to protect the innocent.

I also trimmed the ears from some of these brackets. I actually trimmed a couple that didn't need trimming. The plans indicate it's OK to put an AN426 flush head rivet under flange, but I trimmed the flange so that I could use all AN470 rivets to attach the F-705B and the two F-605Cs to the F-705A. I also made sure the flanges of the brackets would not interfere with the ribs they're adjacent to.

These are the F-705J angles is for the seat back incline adjustment. I laid out the nine holes and drilled them through one angle...

...then clamped the other F-705J angle to the back of the first and transfer drilled the nine holes in the second angle.

Again, I'm using a piece of scrap (leftover from cutting the F-705B) to hold the angle off by 1/8 inch while drilling the holes.

Match drilled the F-705D to the two angles, deburred the holes, and called it a night.