Small parts, small progress

A bit of a late start today.  I’m back from my second week on the job in Chicago and I got my first paycheck.  Yay!  Alas, the first paycheck is a paper check, so I had to wait for the bank to open.  Now my account is flush again.  Plenty of money to buy more tools!

I picked up with the aileron mounting bracket where I left off… a pile of small parts.  The parts still needed a bit of work before assembly.  When I checked over the inner cutouts, they were rougher than I was comfortable with, so i spent some time cleaning up the edges.  Next, there is a lot of match drilling and countersink work to do.  And of course, the hole deburring work!

I got all that done and was able to prime the pieces.  It’s a lot nicer being able to work with the garage door open.  I’m using a respirator, but the fumes clear much faster through the open door.

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I actually found the required bearings without much difficulty (I marked all the bags during inventory).  They are a very tight fit.  I first tried the two socket wrenches and C-clamp method.  That was a bust.  Turning the C-clamp causes the socket to shift whilst tightening.  Next I tried the two sockets in my vice.  Not a lot better.  In the end, I just hollowed out a small block to provide a relief area and used just the 7/16″ socket to push the bearing in.  As you can see, the hollowed out section doesn’t need to be particularly round, it just has to adequately support the end of the hinge bracket spacer.  The block was much easier to control than the large supporting socket.

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I took a break on the aileron hinge brackets and moved on to the spar doublers.  All the pieces so far either were all pre-drilled or used a couple of holes as alignment guides.  These pieces are hand placed, clamped, and fully match drilled.  So we use the “blue line” technique to add an alignment line in Sharpie that we will spot through some holes on the spar to make sure we get good edge distances on the doublers.

I used a gauge to lightly scratch a line 5/16″ from the edge into the blue plastic.

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I followed that up with a sharpie line to make it easier to spot.

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Next, I had to position them on the spars.  I’m doing both right and left at the same time to try to avoid mistakes.  I nearly put the left wing end doubler on the wrong end of the spar.  Check your work, check your work, check your work!

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Sure enough, the blue line show up and the piece is correctly centered!2015-06-13 14.52.17

At this point, I went back and riveted the aileron hinge brackets.  My air hose sprung a leak near the fitting (not so great when I have to turn the pressure up to 90 pounds to drive those 1/8″ rivets), but I was able to patch it up with electrical tape for now.  I did the 426 flush rivets with the hand squeezer (clamped to the table as shown) and the 470’s with the pneumatic squeezer.  The rivets are done in “random” order to try and keep the bracket from twisting.  It came out nice.

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I had to bail early because it’s the volunteer fire department summer clam bake today!

Next week, I’ll match drill the doublers, nibble out the push rod hole, and hopefully finish the rear spars!

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