2 hours.<\/p>\n
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.<\/p>\n
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.<\/p>\n
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. <\/p>\n
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?<\/p>\n
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.<\/p>\n
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.<\/p>\n
This is truly a “come back victorious, or on your shield” moment.<\/p>\n","protected":false},"excerpt":{"rendered":"
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 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[6,10],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=\/wp\/v2\/posts\/317"}],"collection":[{"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=317"}],"version-history":[{"count":0,"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=\/wp\/v2\/posts\/317\/revisions"}],"wp:attachment":[{"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=317"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stjohn.openbar.com\/airplane\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}