Fuselage - Bulkheads

2005-02-12 - Assembling the F-704 bulkhead. (4.0 Hrs).

Today, we fabbed the web stiffeners, riveted on the cover supports, and finished-up the center section--we thought.

Cutting the web stiffeners from the 5 foot piece of 063x3/4x3/4.
Two stiffeners cut, deburred, and the center line marked.
Clamp the stiffener to the forward center section so the center line is visible, then drill.
Each stiffener needs two nutplates (shown here on backwards, so the holes line up with the center line). I wanted these to fit right, so I decided to use a screw to clamp the nutplate to the stiffener before drilling the rivet holes.
I decided that was a bit extreme. You just need the screw to align things, you don't have to screw it all the way into the nutplate. Then, use a cleco after the first hole is drilled. This really does not have to be perfect.
The web stiffeners are attached with flush rivets, so you need to countersink the front of the forward center section web. I used the stiffeners as countersink guides, but the holes really are not that deep.
One F-782 installed. A little too much air pressure on that left rivet.
One F-783 installed. Bolts inserted just for alignment.
All cover supports installed. On to the spacers.
I wanted these absolutely perfect, so I cut them a little long and used the disk sander to get the first one very close. The 3M wheel made it perfect. Then, the second one was sanded down until it was identical. You should be able to hold both spacers with the calipers without either one falling out--exactly 1.438 inches, or as close as you are going to get with a $20 set of calipers.
This hole, as well as the one on the other side and the two on the forward F-704, needs to be enlarged to 1/4". I did a suck-ass job, on the hole. After drilling, I used the 1/4" reamer to clean up the holes, so the final result was ok.
All done (I thought), just need to make the wooden spacers. I looked all over for the AN4-34A bolt, and the only ones that I have are the close tolerance bolts, and there are only 8 of those. They are not in the inventory.
I knew that surface planner would come in handy.