Horizontal Stabilizer

2/16/2011
Hours: 3.0
HS Total: 49.0

Tonight I got the ribs dimpled and the right skin.  The only excitement was when I was dimpling one of the last 5 holes and the skin slipped as I was coming down on the hammer of the C-Frame tool.  The dimple ended up off center and damaged the edge of the hole.  My first thought was, "Oh great.  how many hours?  And now I have to order a new skin."  But then I thought about how I might repair it.  I finished dimpling the holes and scratched my head for a few minutes.

I undid the dimple with the flat sets in the squeezer.  Then I clecoed the stringer in place (this is where the hole was located) and match-drilled that hole for a 1/8 flush rivet.  I pulled the stringer back off, dimpled the hole for a 1/8 flush rivet and countersunk the corresponding hole in the stringer.  It looked fine from the front - perfect in fact.  But from the back, I got a little concerned when I looked really close and noticed what looked like two little cracks.  It was clear that these cracks didn't go through the skin since they were not visible from the front.  But they were there.  I fired up the compressor and plugged in the dremmel tool I have loaded with a little 1" scotch-brite wheel.  I hoped that a few gentle touches on those cracks would prove them to be very shallow.  With great relief I report that they were.  After a few light touches with the wheel, they disappeared entirely.  I marked the spot so I remember to put in a #4 rivet when the time comes.

Stringer with the enlarged, countersunk hole

The damaged hole enlarged and dimpled for a 1/8 flush rivet.


Closeup of backside of hole after being enlarged and dimpled (and with the marker cleaned off).  The two cracks are visible.

If you zoom in, you can still see where one of the crack was because of how the light reflects on the area where the metal has been polished, but it's now smooth across that spot.  Looking at it in person, you'd know something was done there, but you wouldn't know what.


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