Final drill skins?

[Ueli N]

I am a new builder and started to build on the tail section of the RV 12.
So far not too many problems. Rudder completed.
Something bothers me where I need some expert opinion.
In the plans and on the video there is no mention about final drilling the
skins. With my experience the rivets will not fit through the skin and ribs
without running the #30 drill through first, or at least on most holes.
It seems the holes are about 1/1000 th too small.
If the holes are deburred in the first place, there is no burr visible after
drilling.
How are you handling it?
1: deburr all holes, cleco, drill and rivet
or
2: cleco, drill, remove-deburr, cleco and rivet

Any advise please -

[Keith Williams]

I did not drill the skins (well, in just a few places). For me using an awl to align the holes where needed was enough.

[txaviator]

Check out this entire thread. I know you asked about the skins, and even though this thread mentions the flanges, it covers your question:

http://www.vansairforce.com/communit...ht=final+drill

**Like Keith said above, I had to drill a few, but not many!

[Dvalcik]

Get a #30 Straight Flute Reamer

http://www.cleavelandtool.com/30-Str.../#.UnFQE_mshcY

[bobnoffs]

i just got my kit and my experience is that the skin holes are just too small.when a rivit won't fit into the skin only, not attached to anything, the hole is not big enough. if you try a rivit on a few pieces with only that hole you will see that the hole needs a #30 [or equivelent] run thru it. it only takes a .00001 to make or break the fit.
if it won't fit thru the skin alone it is not an alignment issue.

[DEWATSON]

What DVALCIK said.....

[DaveLS]

If a rivet will not fit through just the skin holes then something is wrong.

Try a different rivet. Try a different hole.

I have found that some (very few) rivets are larger than others.

Calling Vans might be in order.

-Dave

[txaviator]

Originally Posted by DaveLS

If a rivet will not fit through just the skin holes then something is wrong.

Try a different rivet. Try a different hole.

I have found that some (very few) rivets are larger than others.

Calling Vans might be in order.

-Dave

It's like Scott (from Van's) mentioned in the link I posted above. Sometimes a tool at the factory may become a bit dull and a hole won't be sized properly, but I'd bet it's rare. I didn't find that to be the case often. I had a few that seemed undersized, but who knows...I could have had a burr on the rivet, or ???

[bird]

Always fit, Cleo, drill, disassemble and deburr. I have found that skins can and will creep on you when reassembling after good fitting and drilling. The single most often mistake I have seen builders make is not using enough clecoes. Get plenty of them and use them. On skins I go every other hole when fitting and drilling, it is important. I know it is more work, but my skins went on great and only on occasion did I need to ream/drill a hole during the final riveting. I bought a lot more clecoes than recommended, especially on the fuselage when you get to that point. This is my opinion on the best way to get a really good fit and finish. Hope this helps.

Bird

[Bill_H]

I would not follow Bird's advice, for the -12. I understand that the -12 skins are thinner and the practices that work well for other RVs do not all apply to the -12! My experience was that an occasional "touch drill" is needed but NOT often. Also do NOT over-deburr! Just a light turn with the deburring bit in your slow-speed power screwdriver.