Got a few more hours to work in the garage on my main spar. I continued to countersink the various holes on the flanges of my main spar. I’m sure I mentioned this in one of my Empennage posts, but I had previously had bad luck with the 3 flute countersink bits and opted to purchase some of the single-flute bits from Cleaveland tool. In each bag that have a warning that its easy to break the pilot off of these countersinks if you apply a side-load on the countersink. HA, I’m sure that warning is for other builders, not me!
HA, did I end up serving myself a slice of humble pie. Trying to countersink the holes on the spar web I ended up putting a side-load on the countersink and broke the pilot off in the hole. Oops! Not a huge deal, just get the pliers out to remove the pilot, make sure the hole wasn’t damaged, then spend a bunch of time getting the countersink cage set up on my original 3 flute cutter. I was concerned due to my previous experience with this countersink, but it worked like a champ.
Next step was to finish drilling the required mounting holes for the tie-down brackets. The first bracket needed a little extra sanding to allow the bracket to just rest against spar step-bar. (13-4: Step 7) The next bracket ended up having a 1/16 gap between the tie-down bracket and the step-bar. Since this didn’t match the wording in the construction manual, I sent a quick note of to Vans. Their prompt reply, “this is perfectly fine”.
The only thing left for the Main Spar section at this point is to spot-prime the main spar, prime the tie-down brackets, install the nutplates on the tie-down brackets and mount the brackets to the spar. Looking at the weather it may be a few weeks for that to happen, so time to look ahead in the construction manual to figure out what else I can work on till the weather improves.