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Match hole mismatch

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SamP

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Nov 4, 2016
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We've started putting together a RV-12 kit, which has match drill holes that we drill to final size. When we assemble pieces together, we sometime note slight misalignments that doesn't hinder a cleco going in, but prevents a pop rivet from fitting in the hole. We've been taking a drill bit and passing it through the hole to slightly widen it, which allows the rivet to sit nicely in place.

My question is "Is this Kosher?" We don't take a lot of metal out when we twirl the drill bit in the hole to wide it up, but we may be forming burrs. This could prevent the rivet from seating correctly after being pulled.

Thanks for your thoughts.
 

D Hillberg

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as you set the rivets the base material stretches slightly causing the misalignment as you progress along the rivet line- either stager the rivets set (set and skip a few holes) or place the rivet shanks in the holes to keep the skins aligned as you work. celeos / wedge locks are a bit smaller than the rivet holes and the material does shift.
 

proppastie

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This if fine, cleco every other hole or rivets as above, but the bottom line is a rivet swells when driven or pulled and then fills the hole and that slight extra you may have removed to allow the rivet to go in the hole. The slight burr will not stop the rivet from seating.
 

Daleandee

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The slight burr will not stop the rivet from seating.
Burrs should be removed to allow the rivet to set completely and correctly & to prevent cracks & stress risers. The light use of a deburring tool is advised:

http://www.aircraftspruce.com/menus/to/hand_deburring_0deburring.html

Dale Williams
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cheapracer

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a rivet swells when driven or pulled and then fills the hole .
This is true.

Vans would use a cnc stamping machine to punch the holes, they should be near perfect every time, so I would be contacting Vans to check your methodology, or for other issues they are aware of.

Your many slight adjustments will add up and likely end up with some ugly panel waving.

Is is wrong for example to do rivets in sequence, do each end, then the middle, then the middles of those, then the middles of those, repeat over and over, always keeping an eye out for waves for which you should attend to immediately by pulling down the center of the wave evenly, then attending to the multiple smaller waves that creates.
 

bmcj

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When I hear you say "twirl" the drill, I picture you doing this by hand instead of with a tool (power or hand drill). Is that true? If so, then the misalignment is very small and should be able to be gently pulled into alignment with a small all, shank, etc. if it is that close, would a reamer finish out the hole rather than a drill?
 

BoKu

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Be careful about how much misalignment you accept. There are a few places in the RV12 kit where they use disruptions in the hole patterns to differentiate between right and left assemblies. So if you can't see through all the holes, double check that you are using the correct parts.
 

SamP

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Nov 4, 2016
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Yes, the twirling is done by hand, and we're not removing much metal. We'd try forcing the rivet in and bent the inner sheet metal. It took a good hour trying to bend that piece back to the original location.

The process that we're following is clecoing the parts together, final drilling the hole, take the parts apart, deburr, re-cleco, "twirl", then rivet.

Thanks for all the tips and suggestions. We've been setting rivets randomly to avoid waves. I think we'll try putting in, but not pull the rivet, before clecoing to ensure alignment on our next part. This will decrease the amount of times we have to twirl or use a #30 rod to push things into position.
 
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