Trevor & Dewey's RV-7 Construction Log


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Date: 12/15/2009
Task: Finished attaching tank nutplates to right spar. Fabricated tie-down brackets

I started the day by working on the right spar tank attach nutplates. I had already predrilled the holes yesterday so I went right to riveting. I started on the top flange, riveted the nutplates, then countersunk them with my #30 countersink using the same OD of 0.370. I then flipped the spar over and riveted the bottom side nutplates. Once I had countersunk all the tank nutplates I changed to the #40 pilot and countersunk the inspection plate holes to an OD of 0.312.

Once all the holes were countersunk I masked off the spar and primed it with NAPA 7220.

Next task was to fabricate the W-731 tie-down bars. They were already the correct size but needed to be drilled 3/16".

I then tapped them 3/8-16 x 1" deep. LOTS of cutting oil used!

Next I cut 4 W-726 spacers out of AB4-187x1.25 material. They are cut into 2" lengths and edge deburred.

I then marked over 1" and down 5/8" to find center

I used my Unibit to drill the holes 3/4". The plans call for 1" lighting holes but I really didn't want to use my fly-cutter. Its a dangerous tool and these spacers are pretty small to clamp down. They are spacers only so I was not concerened.

I then taped the W-726 in place and clamped the W-731 tie-down bracket onto the spar. I used the one bolt hole and a square to align the bracket on the spar and ensure it was square. I then drilled all the holes to #12.

Next I marked through a K1000-3 nutplate for the rivet holes, center-punched, and drilled to #40. I match drilled these holes to the W-726 spacers.

Repeated the drilling on the right spar.

Finally, I primed the tie-down brackets.