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What am I missing here?

Ebeswick

Member
I'm a new RV-9A builder who is currently working on construction of the VS. I have reached the point up to where I need to countersink the lower portion of the rear spar doubler and I am now confused. The plans show as follows:
140yil4.jpg


The problem I have run into is that the AN-426AD4-6 rivet does not fit the corresponding hole either before or after the countersink. Per the plans I have previously match-drilled these holes with a #30 bit. What am I missing here?

Countersink Images
2j13050.jpg

jugzdd.jpg


I apologize in advance for the elementary question. Any advice would be helpful.

Thanks,
Ethan
 
Just run your #30 drill bit through the holes again and the rivet should drop into place. If not, LIGHTLY tap them with your rivet gun without using a bucking bar. That will seat the rivet. Then you can shoot them with the bucking bar or squeeze them.
 
Double check what your using

  1. Double check that rivet is an AD4 and not a AD5 accidentally mixed on with the others.
  2. Double check that you drilled using #30 not number #40. Re-drill to clean up hole.
 
Thank You

Thank you for the tips. I ran the #30 bit through the holes again and the rivets were able to be coaxed into place.

Best,
Ethan
 
One other tip, put a piece of rivet tape over every rivet you are going to drive. (Optional when squeezing.)

That will rivet help keep the rivet from backing out on the first strike with the gun and expanding in the hole, causing the rivet to stand proud of the skin.
 
Thanks

Joe- Thank you for the link and advice. I will look into getting both a #30 and #40 reamer.

Bill- I appreciate it. I will be sure to use rivet tape over the rivets when I go to drive them.
 
If you run a #30 bit through the hole after they are clecoed in place and you have to coax the rivet into the hole, either your #30 drill bit is not a #30 drill bit or your AN4 rivet is not an AN4 rivet. It sounds like you may be using a 1/8" drill bit, which would cause exactly what you are seeing, or possibly got the #31 in the slot of the #30.
 
Duh.

I just looked at my drill bits and I must have accidentally used a 1/8 bit to drill out the holes instead of a #30 bit.

Is this troublesome if I made the same mistake on the ribs and skin of the VS? I have already dimpled the ribs and front spar.

Thanks again for the help.
 
The ribs and skin should all be #40 holes and AN3 rivets. Did you use the right bit for those?
 
I made the same mistake with the different bit. I improperly used a 3/32 bit instead of the #40 bit.

Once dimpled the AN3 rivets fit fine, but I was unsure if I ruined the parts by using the 3/32 instead of the #40, and then dimpling them before I caught the mistake and went back through with the #40 bit to slightly enlarge the hole from the 3/32 bit.

I have rechecked the parts and cracking does not seem to be an issue from the dimpling of the slightly smaller holes on the ribs, or front spar. Should I be worried about microscopic cracks that could have formed from this process?
 
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