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Tip: Countersinking the AEX Rudder Wedge (R-916)

RV7Factory

RV7Factory

Chief Obfuscation Officer
I just completed this a week or so ago and I thought this might be beneficial to others...

The idea of countersinking the rudder wedge caused me a little concern. It was probably the stories I've been told of botched parts (sometimes multimple times), or maybe it was the fancy drilling jigs I have seen pictured on other people's web sites. In the end, my concerns were unfounded, as I found the task to be largely mundane.

I certainly can't take credit for this method, but I can't remember where I saw it. I did however take a few pictures and made a few notes.

Pictures speak a thousand words, so here you go. More pictures and some short notes can be found HERE.

Happy building!

050731_003.jpg
 
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More than one way to skin a cat

I made a simple jig using extra wedge sections and scrap wood.

There is a write-up on Ailerons page of my web site.

The beauty of this jig is it holds the AEX wedge horizontal so you don?t have to hold the CS tool at an angle.
 
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I went through all the different methods of countersinking the wedges myself making jigs and even resorting to using a milling machine. By accident I found out why I was having problems in the first place. I was using my wonderful little Dotco air drill which spins up to 2800 RPM. While buildings the flaps the other day I put the countersink tool in my old cordless drill and it was on the slow speed range. The whole problem of wallowing out the holes and bad looking countersinks stopped. I was simply turning the bit to fast. I simply held the wedge in one hand and the drill in the other. I didn't even cleco it to the table. Of course it took me to the very last control surface to figure it out. :eek:

Live and learn!
Jim Wright RV-9A 90919 wings Arkansas
 
Use slow drill speeds

I used a technique similar to Brad's, but with a cordless drill like Jim. Using slower drill speeds with a countersink cutter makes countersinking much easier.

Pete
 
How to Countersink Perpendicular to the Trailing Edge Face?

I'm having a problem countersinking the AEX wedge perpendicular to the trailing edge of my rudder.

Per the RV-10 plans, I was very careful to drill the holes of the trailing edge "perpendicular to the chordline of the rudder, not the the skin." (Reference Page 7-6, Step 6.)

To facilitate this, I made a small home-made jig that Van's drawing in the aileron practice kit recommends to angle the bit at the 84 degrees from the skin necessary to be perpendicular to the chord line ...

FP03102006A00069.jpg


However, the RV-10 plans then say to countersink the AEX wedge "perpendicular to the trailing edge face." (Reference Page 7-6, Step 12.)

Now that the holes are match-drilled, my #40 countersink bit with the pilot nub causes the countersink to tilt along the axis of the rivet hole, which is 6 degrees off from perpendicular.

Maybe I'm being too picky here, but I'm simply trying to follow the plans.

Has anybody else had this same problem? If so, how did you resolve it? Did you use another countersink bit without a pilot nub? If so, what kind did you use?
 
After trying all the methods under the sun, I also settled on the countesink-into-the-table method shown at the top. WAY faster than clamping jigs on each hole, and I got better results. YMMV.

Roadster, if your table is made of particle board as mine was, or something else soft, you may be able to keep the countersink in-plane with the face if you are careful to keep the drill square. It seemed that the wood was giving slightly, allowing a better angle. That said, I did manage to break one countersink this way -- a one-hole countersink from Avery which they replaced for free -- so be gentle.

In any event, I cannot imagine that it matters much. The RV-9 directions repeatedly talk about not worrying if you get some deformation due to overlapping countersinks (which looks really ugly when it does happen...)
 
Thanks for the feedback, guys. I ended up using a deburring bit instead of the countersink bit with the pilot nub. That solved the problem. I also built a quick fixture based upon Bill's photos that really helped maintain a perpendicular angle using my drill press. (Thanks, Bill!) See photos below...

Countersink fixture mounted in drill press...

FP05102006A0001A.jpg


Fixture in use to maintain 90-degree angle...

FP05102006A0001B.jpg


Countersunk wedge, along with fixture and templates for visual reference...

FP05102006A0001C.jpg
 
t.e. strip

I got a hold of a freinds matching rudder T.E. and plan to cleco the two strips together (alternating the angles giving me 0* to the table top)
drill/countersinking without the use of special jigs everything is 0*. Plus the benifit of countersinking two parts at the same time (clecoed together, flip it over) I'll use the drill press after my drill press comes back from having some warrantee work done :mad:
keep it simple :)
 
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A new jig idea?

Forgive me for resurrecting an old thread, but in my lurking through the forums, I did not see a good method of building a jig for countersinking the AEX rudder wedge.

I had an idea to use a block of wood as a jig to countersink the trailing edge wedge. I cut an angled groove (approx 9 or 10 degrees) in the center of a piece of oak with the table saw. It took a few scraps and a few adjustments but I dialed it in so that the wedge sat in the wood block with the exposed side perfectly level with the face of the block. This allows the countersink cage to be properly supported when countersinking the holes. I drilled a #40 hole in the center of the piece to allow the pilot of the countersink bit to go through. It worked better than I imagined! Holes came out perfect!

http://4.bp.blogspot.com/-f5Q7y0LnkvM/VhXZ6i8YltI/AAAAAAAABCY/demebm_ld1M/s1600/IMG_5853.JPG
 
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