SB 14-01-31 pt 6

Whew…more fun. Tonight I got the doublers fitted and all the drilling done…and there was quite a bit of it.

As of last night I’d clamped the doublers in place, but not really done anything in terms of positioning them or anything. That was what started tonight – lots of tweaking the position while peering inside the stab body with a flashlight and examining the lines I’d drawn. Once I had them aligned the way I wanted, I decided that in the spirit of “measure twice, cut once,” I’d mark each hole location with a Sharpie and remove the doublers just to make sure the locations were good.

Here’s the result of that – good edge distance all around:

Then it was just a matter of clamping them back in place, carefully aligned, and getting started on the drilling…and as mentioned before, there was a lot of it – 30 holes per doubler, many requiring use of the angle drill at awkward angles. Unfortunately, this didn’t go completely well – it turned out that the first #30 bit I was using had gotten dull, and I didn’t notice immediately. The result was that, for a couple holes that were drilled using the spar web as a guide, the bit ended up wandering a bit and widening the hole in the spar web. These spots will need to be opened up to a larger size and I’ll use a 5/32 diameter rivet in them. The real fun here is that all of these holes are common between the ribs, so I’ll have to open the holes with all the parts in assembly, and limited access. The good news is that there’s plenty of extra material around these holes, so edge distance shouldn’t become an issue when enlarging the hole.

Anyway, here’s the scene after I finally got all the holes drilled – just a solid forest of clecos:

That’s enough for tonight. Next, I get to remove these doublers, see if all the holes ended up looking decent, and do a bunch of deburring. Then it’s on to fabbing up the new angle flanges for the main ribs. Before long it’ll be time to so some really fun tight-quarters riveting!

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