<December 5, 2007>
Drilled Flap Bearings
Another small task night. It seems that there are all these small tasks to finish up before I can put the Center Section together. Actually, I think I am just procrastinating from all the deburring I need to do.
My goal is to have all the deburring and priming done this weekend with the Center Section assembled and ready to rivet (probably next week). Slow progress, but I'll take it over no progress at all.
I just couldn't leave good enough alone, I had to make a few more adjustments to the flap bearing blocks. I sanded another 1/64" off the bottom and also trimmed the tops even. Now at least I have two blocks that match each other dimensionally.
Since I had altered the dimensions of the blocks slightly from stock, I drew centerlines down the front face of the block. Actually, that's not technically accurate. The line across the block is centered on the predrilled hole, not the overall block dimensions, while the long line is centered on the face of the block. I will work from the center of the hole rather than the center of the block. I then marked my dill holes taking into account the difference in block sized I created by sanding them even. Clear as mud?
I then used my drill press to drill the one hole in each block with a #10 drill. Normally I would use a #12 for AN3 bolts, but #12 doesn't work for plastic. The drill press was needed here as I don't trust my ability to drill a straight hole through something this thick by hand. It worked out well.
With a hole in each, I mounted and clamped them to the bulkhead, aligning the marks on the block with the other hole. Using my hand drill I drilled through the bulkhead and into each bearing, but only to a depth of ¼". I then removed the blocks from the bulkhead and I was easily able to finish the second hole in each on the drill press by using the starter hole in each to align the bit.
Perfection! The lines you see were accidental. As it turns out, I marked the wrong side of the block at first. I had marked the aft side when I needed to mark the front. Oops.
One more miscellaneous center section task to address. I still had two more bushing holes to cut in the flanges of the baggage ribs. Same as before, I started with the carbide cutter and finished with the sanding drum (in the Dremel). I think that does it for all the small center section tasks. Time to deburr and prime, yuk! I will install the nutplates on the ribs after they are primed.