After thinking about it a while, I decided to go ahead and order parts to build a new vertical stabilizer spar. The pieces are relatively cheap and I'll feel better about the airplane. The old spar could probably have been made to work just fine, but I don't want to be lazy and accept work I know isn't as good as it could be.
Also ordered some NAS1097 rivets, which will probably come in handy later on when riveting skins.
Occasionally, living in Kansas has its advantages – like the way I can order something from the Yard Store in Wichita and it gets here the next business day for like six bucks. Here's the new (rebuilt) rivet squeezer I received today:
It is a clone of the Chicago Pneumatic CP-214, but I don't know who actually made this one. It looks like it was built when FDR was president and has obviously seen a lot of use, but it still works great. Those 1/8" AD4 rivets I was having trouble squeezing by hand are no problem for this guy. In fact, a typical work session with the pneumatic squeezer goes something like this:
Me: Here is a rivet that needs to be squeezed.
CP-214: DESTROY!!!
You get the idea. The folks who say this is the most useful riveting tool they've ever bought are speaking the truth.
Here I've set the rivets in the center elevator bearing assembly I was working on the other day:
…and then drilled the bolt holes that will attach it to the HS spar:
Then I switched back to the vertical stabilizer spar, seen here resting in the grass after receiving a little primer touch-up:
Although it looks okay in the photo, I'm not totally happy with the way it turned out. For one thing, I foolishly damaged some holes by trying to drill out three rivets with the wrong size drill bit. Must double-check drill size next time. Those holes will have to be filled with bolts, probably, so there goes the weight savings I picked up by cutting the optional lightening holes.
The other thing I don't like about the VS spar is that I oriented the rivets so the manufactured head is on the forward (internal) side and the shop head is aft (outside). While this is a purely cosmetic issue, it bothers me that I didn't think about which way I was going to put the rivets in so the pretty side would be out. Yes, this is extremely picky, but I am considering chalking this one up to practice and ordering new parts to build a replacement VS spar with the lessons I learned on this one. Stay tuned…
Okay, I said I was going to build the vertical stabilizer first, but then I got to those @#$% AD4 rivets in the VS spar. I was resisting the purchase of a pneumatic squeezer, but that only lasted till about the third one of of those suckers. I guess I could hit them with the rivet gun, but I'd just rather squeeze 'em, so pneumatic it is.
So, while I wait on my rebuilt pneumatic squeezer to arrive from the Yard Store, I switched to the horizontal stabilizer. I figure I can get some prep work done there in the meantime. Here I've deburred and polished out the milling marks from the HS rear spar reinforcement bars:
…and match-drilled them to the rear spars:
Drilled the rivet holes for the center elevator bearing:
And, since I must wait on the squeezer to smash those rivets too, it's on to the front HS spar reinforcement angles. Drilled them to the front spars, then marked and cut the tapered sections. Not shown is the half-hour with the hacksaw and vixen file, plus bad language, that it took to get them looking so nice:
Then the ears on the reinforcement angles get bent to exactly 6 degrees to accomodate the sweepback of the front spars. The manual calls for you to clamp the ears in between wood blocks and beat on them with a hammer, but I found the aluminum was soft enough that I could just clamp the parts at the bend line in a padded vise and bend the ears by hand.
Note the aircraft-quality angle bending template.
Not much time to work on the project tonight, but got the vertical stabilizer rear spar clecoed back together:
This is my DRDT-2 dimpling tool. It's more expensive than the usual C-frame dimpler, but it rocks. It's easy to dimple one-handed, it's stress-free, and it makes no noise so I can dimple at night without waking up the neighbors.
I used the well-known trick of removing the blue plastic along the rivet lines using a wooden straightedge and a soldering iron, and it worked great.