Next, I drilled all of the nutplates in the F-715 ribs. (I'm getting tired of nutplates).
Next task that needs to be done is to drill the tooling hole out on the F-715 rib to 5/8" for the electrical wiring/pitot tubing (As called for on drawing 28/Side skins). I decided to drill the hole to 1/2" for now....I can open the hole up to 5/8" at a later time. I'm not 100% that this will be the pitot tube routing so hence why I'm reluctant to open to the full 5/8". I error on the side of caution in this case.
Next task that I want to get sorted out was that I was never happy with how I drilled the F-661EF flap bearing blocks. They way I was doing it was that the holes that met the F-705 bulkhead were spot on, however the holes on the opposite side of the flap bearing block where a bit skewed off to the side. Not parallel and perpendicular. Much has to do with the fact that the block material distorts when you are clamping it to the drill press, and the other is that you are drilling quite distance all accentuate the possibility of error. After a number of previous attempts at drilling these...There's quite a trick to learn. 1st step is to mark out the proper hole location on the block....But on both the forward side and the aft side. Then set up and drill with #40 halfway through the block....Flip the block over and drill halfway through the block on the other side. If you have done the measuring correctly....both holes with line up correctly. Keep repeating this process with #30, ~#20, then finish with #10. By the time you get to this point you will be able to run the #10 drill bit through the entire way and the hole will be perfectly parallel and perpendicular. I then could mount the assembly and start marking out the top most holes.
Repeat the lengthy and painful process for the top most holes. The result is a perfect fit and the bolts will be perfectly parallel and perpendicular. (Not slightly angled)
