2 hours.
Drilled the left wing. Everything was lined up, everything went perfectly, everything was easy as pie. Then I went over to the right wing. I measured and checked level again, then locked in my drill guide. I almost got through when the 12″ drill bit broke off in the guide block. Then the remaining nub snapped again when I tried to extract the guide block and drill bit from the spar. Oops.
There’s that feeling you get, I know everyone’s felt it at one time or another, and if you haven’t, you haven’t lived. It’s that sinking feeling in the pit of your stomach, when the world does a traveling zoom, where the only thought running through your head is ‘I am so utterly, completely, well and truly f**ked.’ Before the urge to throw breakable things takes over, it’s good to breathe, look at what’s going on, and come up with a plan. The facts: I have a drill bit broken off, pinning 3 layers of aluminum together. I have enough edge distance to completely drill around the broken bit to facilitate extraction.
First step was to drill alongside the broken bit. A relief well, if you will, to see if that would allow me to wiggle the broken bit out the way it came. I tried drilling out a #40 hole to see if that would loosen things up. No joy. Next was to see if I could just go up a couple of drill sizes (#3) and pulverize the stuck bit while drilling through along the same path. I got just past the first layer (aft part of bracket) when the #3 bit started to spin and wouldn’t cut into the broken bit at all. Back away. Back away before you make it worse.
So I pondered, and then had a hunch. What if I can move the wing spar relative to the bracket? I unclamped everything, making sure to double check that my sweep and incidence positions were marked and gave the wing a jiggle. YES! The spar end slid inside the bracket, which meant that the broken bit wasn’t pinning all three layers, just the first two. So what to do now?
Take the damn wing off. With the wing off, I can get at everything and backdrill to the broken bit from the forward side, then pound it out with a drift punch and a hammer. The broken bit will be right below the #40 hole, so with a good guess, I can put another #40 hole below that one and hit the tip of the broken bit, all without compromising my edge distance to the sides of the bracket or the spar. I have to tread very, very carefully now. This has the potential to be a nasty incident pit.
And if I fail completely, I can have the bracket and spar welded up and redrill it. I think. Might have to contact tech support on that one. Best policy is not to mess it up.
This is truly a “come back victorious, or on your shield” moment.
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