I clecoed the F-01412A and F-01412B bulkheads to the vertical stabilizer using the two locators holes. I match drilled the #30 and #40 holes per the plans, and enlarged the systems hole to 1/4 using my step drill. I clecoed the tie down bracket to the bulkheads and vertical stabilizer and final drilled #12 the four holes indicated in the plans. The bulkhead assembly will be attached to the vertical stabilizer later using these holes and AN3 bolts.
I removed the tie down bracket and bulkheads from the vertical stabilizer and deburred the parts on my bench grinder with the scotch brite wheel. On the curved portions of the bulheads I used the scotch brite wheel to round over the faceted edges.
I dimpled the #30 holes in the web of the bulkheads for an AN426AD4 flush rivet. I machine countersunk the four holes in the tie down bracket for the four holes in the bulkheads that were dimpled.
I dimpled the #40 holes in the flanges of the bulkheads, except for the ones that were not to be dimpled per the plans. I also dimpled the optional #27 holes in the flanges for the access cover. This will allow for a flush screw installation later.
