Another Long Day with the Flaperon

These flaperons sure are a piece of work! Today was the day to match drill the counterbalance tube and I had dreaded this job. Apparently the steel drills much slower than aluminum, giving the drill bit ample time to drift off and elongate the softer aluminum used as a guide to start the hole. The forum was very helpful how to deal with this issue and I decided to go with the mark or dimple (by just starting to drill a hole with a #40 bit) the steel and then drill the hole using the drill press with a tube support to hold the tube in place. I tried to be very careful again and took a lot of extra steps to make sure the holes would end up in the right place but I did not succeed with three of them. The bad thing about it is that I actually don't know what happened and how I screwed it up. Which is particularly bad as I will have to do another flaperon and have yet another set of chances to do the same (unknown) mistake(s) again.
I don't think the screw up is so bad that I would have to get replacement parts and it appears to be fixable but still my ego is hurt. With all the extra effort I took to make sure it was done right I didn't really expect anything like this. Mainly slightly displaced holes that in order to match drill them caused a slightly elongated hole. The rivet seem to have good grip though and it's in a non stress area, just holding the skin down, so I guess I'm good.

So, this is what I did. Placing the tube on the outboard nose ribs and marking the holes to drill with a Sharpie.


Then taking it apart, pre-punching the marked holes and putting the steel tube in the drill press. Use lots of Boelube, slowest RPM on the drill and don't press too hard. I actually relieved the pressure on the drill every other moment and pushed it back down thereafter to allow the oil to get down in the hole. I drilled the first hole with a #40 and then opened it up with a #30.


Put the tube back on the ribs, put a rivet in to see if it fits nicely - it did.


Now it was to put the skin on. I didn't rivet the two ribs to the tube yet as I wanted to mark the holes in the nose skin and then drill the holes on the drill press again and the ribs would have been in the way for that.


You really want to make sure you flute these two ribs thoroughly or you will see the edge protruding under the skin like this!


So back to the drill press it was. Unclecoed everything and also re-fluted that outer rib that would show. Fluting alone wasn't enough, I had to add some stronger deforming powers in form of my thumbs and unbeatable will.
Here I am drilling the holes I had dimpled with a #40 bit when the skin was clecoed on. I am drilling with a #40 again and I intended to do the match drilling to #30 with the hand drill when the skin is back on in case there were slight misalignments.
I also didn't just start drilling into the tube. Just as I had done it before with the two holes matching the ribs, I started the drill with some pressure and my hand turning the spindle to make sure the drill would stay in the dimple and start without wandering off.


Well, and then back to clecoing in the skin over the tube. That's when I noticed that the further I went towards the inboard end the harder it was to get those clecos in. It looks like a warping issue as it felt like it was progressing. The three inboard holes have elongations with the most inboard one having the worst. Before I was dimpling the holes I made sure the spar was sitting on a flat surface and that no forces could bend the spar. I have no clue at this time what caused this. Bummer!
Anyway, I match drilled as I had intended to and that kind of fixed the problem with the aforementioned elongations.
I took all the parts apart and deburred the holes and edges and threw some rattle can primer onto the surfaces that will have contact.


Although my mood was abit down after this episode, I kept on pressing and riveted the inboard actuation ribs.


I also match drilled the actuator bracket and the two hinge brackets for the left flaperon, deburred and cleaned them and threw some primer and let it sit over night to dry before riveting them on tomorrow, if I find the time.