I saw this neat tie-down anchor a few weeks ago at Nancy’s Airport Café in Willows, CA. It was in an RV-6, N213JM. I thought it was a good design, well worth borrowing, so with permission from the owner, here it is.
I started with a piece of scrap aluminum angle. I drilled a couple of pilot holes approximately 1/3 up from the apex of the angle, and then used a Unibit step drill to enlarge the holes until the edge of each hole was even with the opposite side of the angle. All measurements were done by “TLAR” (that looks about right)!
The two center holes in Fig. 1 are what I am working with. The other holes were already there, but will not be used—as I said, this is scrap material, so I just used what was available.
In Fig. 2, I have cut off the end of the angle, just barely cutting into one of the holes I drilled and enlarged with the Unibit.
As you can see in Fig. 3, I cut off the extra material near the second hole and did a bit of shaping on the top edge of the piece of angle to get rid of the sharp corners. Next, I drilled a couple of holes to rivet the cleat into place. When the photo was taken, no deburring or finish work had been done.
In Fig. 4, I did a test fit with a bungee cord—looks like it will do the job. It still needs a few minutes with a file and Scotch-Brite wheel. Total time to make the cleat was not even five minutes—way less time than it took to type up this article!