Sonex 1404

Posts Tagged ‘AN4

Making the wing attach blocks from the 6061 bar stock proved more difficult than I thought. I tried using my miter saw to cut the stock but ended up burning the motor. I bought a chop saw and put a non-ferrous cutting wheel which did the job beautifully. I used the Scotchbrite wheel to polish the blocks a little and remove the manufacturing marks.

The next step was to drill the holes to mount the blocks to the brackets and also the pilot hole for the spar carry through bolt. I practiced on a scrap block first. I up-drilled from 3/16″ all the way to almost 1/4″ in 2-3 steps and finally reamed the holes out to AN4 size for a perfect fit. Reducing the speed of the drill press and using Boelube helped a lot.

The last step was to put the AN4 hardware on. The bolts slid in with no play at all, and the nuts were torqued to about 50-60 inch-pounds.

Next step is to mount the attach blocks and other angles to the wing spars and complete it.