Tuesday, October 6, 2020

Marking the brake line holes in the bottom skin - 2 hours

 One of the items I noticed was quite right was the alignment of the holes in the gear weldment and the pilot hole in the bottom skin for the brake lines. They don't exactly line up as well as some of the other pre-drilled parts. I decided that I will open the holes so that they align. First job is that I need to mark the holes.

 I clecoed the bottom skin on and fitted the gear weldments.

One of the items you have to pay attention to is that the most forward hole in the bottom skin (that is a the center) gets drilled out to #12 for future U-720A on the tri-gear RV's. Since I am building the 7A...I need to do this. I'm reluctant at going the full #12 now, so I just opened the hole to #30 so I don't accidentally dimple/rivet it. 
 

Now that its all together you can see how the pilot holes line up. One is decent, and the other is a bit off. 


I scratched my head on how I was going to mark the correct location on the bottom skin. I finally came up with the idea of using a paper tube to diameter of the hole in the weldment. I dipped that paper tube in white paint which I was able to stick through the weldment hole and mark the bottom skin. It worked very well.


I will open the pilot holes up just a bit (not to the full 5/8" opening). Then once the fuselage is fitted together and the parts are in their final position, I will use the dremel and files to open up the holes in the skin perfectly centered.



 

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