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Rudder horn hole elongation

stigaro

Well Known Member
Started to work on my RV-14A rudder recently and while final drilling the rudder horn (R-405PD) to bottom rib/spar assembly, I noticed my holes were slightly elongated (between 0.010" to 0.020"). Not sure how this happened, but I know this is out of spec for AN470AD4 rivets (0.125"-0.135" hole size). Anyone know if this is still OK or if it's possible to drill these out to AN470AD5 rivets? Or should I just scrap these and do them over? I have sent an email to Van's as well, so hoping to hear back from them soon.
 

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Non-Van's answer: Use a longer rivet to fill the hole. Rivets are good in that they expand to fill the hole, but you'll need the extra material to ensure a proper shop head.
 
Good to know about dull drill bits doing this. I used a new #30 spiral reamer for this but I wonder if the holes were a bit smaller in the rudder horn compared to the thinner sheet material and as a result the reamer tended to wander a bit going through the horn. I did notice the reamer seemed to cut out more material than I thought it should have at the time.
 
I have seen a lot of this, and the engineers at Vans usually suggest if the edge distance is sufficient, and the material is thick enough, go with the oversize rivet.

Gary
 
I had just this on my elevator. I ran it past my inspector (I’m in the U.K.) and I drilled the holes out round and went up to the next size rivet AN470AD5.
 

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surprising to read a reamer did these holes. the purpose of a reamer is a round hole. the problem must be in the drilling operation/drills as suggested.
holes must have already been too large when the reamer got there.
 
What did Van's say about this? I did pretty much the exact same thing with my reamer, despite trying hard to keep the drill square. I have some AN5 rivets on order.

How are you experience folks avoiding elongated holes when drilling through thick layers? I've got another one on the horizontal stabilizer doubler when match-drilling the inboard nose ribs. Frustrating.
 
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How are you experience folks avoiding elongated holes when drilling through thick layers? I've got another one on the horizontal stabilizer doubler when match-drilling the inboard nose ribs. Frustrating.
Make sure you are spinning the drill bit as fast as possible - that's what's nice about the air drills - they turn fast. And of course use good quality, sharp bits.
 
Started to work on my RV-14A rudder recently and while final drilling the rudder horn (R-405PD) to bottom rib/spar assembly, I noticed my holes were slightly elongated (between 0.010" to 0.020"). Not sure how this happened, but I know this is out of spec for AN470AD4 rivets (0.125"-0.135" hole size). Anyone know if this is still OK or if it's possible to drill these out to AN470AD5 rivets? Or should I just scrap these and do them over? I have sent an email to Van's as well, so hoping to hear back from them soon.

Worst case scenario, the holes are spaced far enough apart, when doubt, you can use AN-5 rivet, no worries!

DAR Gary
 
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