Stabilator spar box and ribs

Page 9-2 has us separating hinge brackets, spacers, and doubler plates; final drilling holes, countersinking, and deburring.  With the right tool, deburring holes is fairly routine by now and goes quickly.

Didn't have any issues (I hope) following the instructions on pages 9-3 (prepping the spar box) and 9-4 (installing the counterbalance arm bracket); don't have any interesting stories to tell (Chinese curse: may your day be interesting); didn't take any pictures; and I'm behind on my blogging so I'm skipping past those pages.  I just hope that I got the nut plates for the upper and lower stabilator horns riveted in the right place.  If the horns don't bolt in just right, it would be bad.  Really bad.

Page 9-5 has us cut a short piece of aluminum tube into four shorter pieces of aluminum tube.   They'll be used as hinge stops.

It's actually quite a PITA challenge because the prescribed length is 21/32nds of an inch, plus 1/32nd or minus 0/32.  When was the last time you saw a ruler marked in 32nds of an inch?  Since metal is much easier to remove than to add back on the strategy is to cut slightly too long and nibble it ever so delicately down to a target of 43/64ths of an inch (0.672") with a Scotch brite wheel.  At 43/64ths the tolerance range is +/- 1/64th (+/- .016").  The only way to measure that is with precision calipers, which, lucky for me, was included with all the other tools loaned to me by a guy at work.

It was difficult making the ends perfectly square, but the final tube lengths came out to 0.666 +/- .004, 0.674" +/- .003, 0.676 +/- .002, and 0.672 +/- .001.  Two were ground down below spec. (Rats!)  I suspect that's why Van's included two of the tubes in the kit.  They know.

On Page 9-6 Van's suggests that "A great way to form the radius [of the rib tips] is with a fine file." Since there are 8 foward ribs (and, thus, 16 tips to radius), I think they say that to get a laugh, like the instructions to use a metric crescent wrench.  A scotch-brite wheel is wayyy faster and is the one indespensible tool if you want to get the plane done before it's time to move into the old folks home.  Here's the before and after picture:

Attaching the ribs on the spar is encouraging because you know it won't be long 'til the skin goes on, which, in my case, will free up a lot of space on the shop table.  The pop rivets used are fairly dummy proof, but unfortunately the tiny space between the rib and rivet post makes it hard to get a pop rivet tool on the rivet post.

That's what these little wedges are for.  Sometimes you use one, sometimes two.  Sometimes you start with two and then switch to one.  The instructions don't really say.  They help you get the rivet tool on the post, or mandrel, and pull it at an angle till it "pops" (breaks off).  Bending the rib over a little bit helps too.

Speaking of rivet tools, I've been lobbying a coworker to let me "try out" his pneumatic pop-rivet puller for months.  I think I'm finally wearing him down.  Just in time too.  The two stabilator skins use almost 600 pop rivets.  Once he realized that it had a lifetime warranty he seemed a bit less concerned about me borrowing it.  Smart guy.

And now we have a nice rivet in a very hard to get at location.  Whew!  Just 30 more to go...