Lower cowl hinge drilling

So while I’m still not 100% sure what I’m going to do for my cowl pin covers, I’ve decided that figuring that out doesn’t need to stop me from moving forward on getting the hinges in place. So a couple nights ago, I measured the hinge locations for the fourth or fifth time, and then cut my hinge stock to make the two pieces. ThenI did some marking on the cowl for the rivet locations, and figured out how I wanted to lay out the rivet lines.

Tonight I actually broke out the rivet fan to mark the rivet lines, clamped the lower hinge halves in place and drilled the ~70 rivet holes for those to mount. Now that that’s done, I get to figure out how to handle drilling the upper cowl hinges. Before I can do that, I’m going to have to go back and bevel the hinge halves that connect the upper cowl to the firewall. Right now, the upper cowl has to be slid in place from the front, but that’s not going to work once the side hinges are drilled – it’ll have to drop in place. I’ve been putting this work off for a little while.

Another fun question is how I’m going to brace the back of the hinge against the upper cowling. At the front, I should be able to reach through the air inlets and get to the back of the hinge, but once I get to where the cylinders are, that’s probably not going to work any more. Maybe if I work front-to-back, I can count on each location being held in place by the preceding cleco? Not sure how I feel about that, even using a wood block to back the lower hinge, the drill bit wanted to push it away in a few spots. I’m not sure I’ll have any choice, though…if I try and do this with the cowl halves off the plane, I lose a lot of control of proper alignment between the two.

I’ll probably just have to sort of grin and bear it in the end…

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