CHAPTER 37 - Adding the Baggage Floor Ribs
I assembled the F606 parts over a piece of particle board, drilling #40 holes at the F606C locations and the attach points for the Baggage Compartment Rear Wall. With the bulkhead clecoed ot the particle board, I marked the centerline on it and placed it in the jig. After positioning and clamping the bulkhead to the longerons at the correct fore/aft location, I marked the lateral line (longeron to longeron) across the board and drilled a 1" hole at the intersection of the lines, so the laser sight line could pass through. Next I centered and shimmed the bulkhead and clamped the longerons to the jig. In the first photo I have circled the sighting hole and markd an arrow to the left side shims. For some reason, that side settled in the center, requiring a lot of shims at F605, F606, and F607.
In the photos, you can see some modified detergent bottles being used to hold clecoes. I'd like to give credit for this idea; I got it from an RV site off the web. However, I can't remember which site - I just know I didn't think of it, but it sure works great! Before this I was using cardboard boxes, with predictable results as the load of clecoes grew..
The next bulkheads were assembled with 3/16" clecoes through the tooling holes and temporarily positioned in the jig. Again, I used some angle stock and cleco sidegrips to hold the bottom of the bulkheads in position. I followed the same sequence as the seat ribs, attaching the ribs at the front first. This is where I discovered that the F626 rib would require me to drill out yet another rivet on the F605. I Also found that the F623 ribs forward flange needed to be trimmed in order not to interfere with the F605 splice plate. This left me with barely sufficient edge distance; had I known of this in advance I could have shifted the rivet line 1/16" outboard while attaching the seat ribs. Still, it will be Ok.
After making the front attachment, I marked and attached the ribs to the F606 bulkhead. I found that the inner ribs required their flanges to be rebent to fit correctly. Again, during this process, I used an aluminum rule to make sure the ribs were flush with the bulkhead flanges and that the bulkheads were the correct distance apart. Now comes the rear structure.