Initial Prep (Debur, Trim, Drill, and Cut)
7/20/23 - 0.8h
7/21/23 - 1.7h
7/29/23 - 0.9h
7/30/23 - 0.4h
The torque tube-to-bellcrank pushrods are made from 1 1/8” O.D. aluminum tubing that has to be cut to length. I tried a couple different methods to measure the length of the tube, and eventually settled on my 40” aluminum ruler and a couple of blocks clamped at strategic locations on the work bench. One block was clamped to the end of the bench as a backstop, and the second was clamped 24 1/4" from the first block as a stop for the 40” ruler. The result was the end of the tube placed against the end backstop lined up with the end of the ruler placed against the other block for a total length of 64 1/4" as specified in the plans. This setup made accurate measurements very easy. After marking the distance on the tube, I used a tubing cutter to make a straight, clean cut at the distance mark.

The next task was to drill the 6 pilot holes in each end of the tubes according to the template provided in the plans. I taped the templates in place, and marked the center of each hole with a center punch. I went to the drill press after marking the hole locations to drill the pilot holes followed by some light deburring to allow the threaded rod ends to slide into the tubes.

The threaded rod ends went into the tubes without any drama or additional sanding to make them fit. After aligning the top of the cylinder section with the end of the tube, it was back to the drill press to final drill each of the holes. I then marked each rod end and tube so I could align the holes the way they were drilled for final assembly, removed the threaded rod ends, and deburred the holes. I found a Dremel with a barrel sanding bit was a good way to debur the inside surface of the holes.
[Hole and Edge Deburring Tools, Tubing Cutter, Ruler, Center Punch, #40 Drill, #30 Drill, Drill Press, Dremel with Barrel Sanding Bit]

Prime
7/30/23 - 1.0h
8/1/23 - 0.1h
8/2/23 - 0.2h
I decided to focus on priming the inside surfaces of the pushrods first, starting with the threaded rod end interiors and exterior cylinder sections. I inserted the rod end bearings to prevent primer from clogging up the threads, which also made a good handle for priming. The surfaces were scuffed lightly with a Scotch Brite pad, cleaned, and degreased. I taped off the rod end bearing and cone portion of the threaded rod ends. The plan was to rivet the threaded rod end into place after priming the interior sections and the interior of the tube, and then prime the completed pushrod exterior.

Priming the tubes is interesting. They are long and narrow, so you can't apply direct spray inside the tubes beyond a few inches. I started by scuffing the inside with a flap wheel that I made from a Scotch Brite pad on the end of a long piece of PVC. I inserted the PVC into a drill, and then ran the Scotch Brite pad through the tubes a few times to scuff the insides for primer. Scuffing was followed up by ramming a clean cloth through each tube a few times to clean out any debris from cutting, drilling, scuffing, and deburring the tubes. I held the tube up to the light and looked down the interior length to confirm it was clean. I degreased the ends a few inches into the tubes to clean up areas that I had touched before spraying.

I tried to spray the tubes in a vertical position as much as possible. I went very heavy with the spray from each end, and rotated the tubes between spray blasts to help spread out primer runs. The runs were intentional in this case to help insure coverage toward the middle of the tube. I noticed a cloud of primer exiting the opposite end of the tube I was spraying from, which gave me confidence that primer reached the entire length of the tube from both ends. It was hard to see if the primer coated completely, but I didn't see any shiny areas inside the tube like I did before spraying, so I feel like I got some coverage everywhere.
[Maroon Scotch Brite Pads, Dupli-Color Degreaser, Rust-Oleum Automotive Self Etching Primer (Green – Rattle Can)]

Assemble
7/31/23 - 0.4h
8/1/23 - 0.7h
8/3/23 - 0.3h
The parts for the Torque Tube to Bellcrank Pushrod go together very quickly. Each end cap is secured with six blind rivets, the jam-nuts get threaded onto the rod end bearings, and then the rod end bearings are screwed into the threaded rod ends. The job is finished by adjusting the rod end bearings to a total length of 67 7/16”. That length may need to be fine-tuned later, so I decided not to torque down the jam-nut until after the aileron control is rigged properly.
[Rivet Puller]