The bulkheads have some bolt holes that are used to hold the bulkheads together after they've clasped a "lower drag fitting" (see page 29-03). These holes should have a tight tolerance. The holes in the bulkheads were reamed to size at the factory (as verified by consulting with Van's). However, the holes in the mating angles and bulkhead webs have not been. The builder is tasked with reaming them him/herself once the parts are mated.
To properly ream, one ought to use a drill press to prevent the introduction of an incorrect bit trajectory. Negotiating these bulkheads on a consumer drill press is difficult. So I enlisted the help of a friend with a legitimate shop that has a milling machine and more spacious digs for the task. Well, turns out things didn't go well at all. Below are some pictures showing some of the holes with and without the proper bolts. The issue is obvious.
I believe the problem was caused by the reamer not being properly lined up with the holes to be reamed. I think the reamer came in at an angle. Lots of material came off the reamer and the lubrication got hot enough to smoke.
Unfortunately, this is an example of always being sure that you understand every element of the work being done, especially when someone else is doing it for you. I let my guard down and should have being more proactive in involving myself in this process.
Anyway, the parts needed to be replaced. For the curious, new bulkheads cost $575 for the forward and $540 for the aft. Angles cost $11.10 each for the forward and $19.30 for the aft. Cover ribs are $12.00 each. So that's a good time.
Click here to see the post involving the redo of these parts.
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