drilling through mated parts

[prkaye]

Suppose you have riveted two parts together so they are sitting flush and tight against each other. Suppose you wish to add a third rivet for added strength. So you drill a hole through the mated parts for the third rivet. You can deburr the sides of the hole on the outside faces of the parts, but obviously you can't deburr the hole on the inside faces, where the parts are mated together (or is there some way to do this?)
Is this a big deal, or do burrs not really form between the mated parts?

 

[briand]

The mil-spec does NOT require disassembly just to deburr.

But why are you just adding extra rivets. You better be sure they won't violate any edge distances or cause any interference issues. I wouldn't do it.

 

[Paul Eastham]

Hi Phil,

If the parts are truly tight against each other, and all layers are aluminum, I usually do not get a burr on the inside layers. If they are not tight together, you might get a burr, but you might also be able to knock some or all of the burr off with a chip-chaser.

And then you've got the riveting mil-spec , which surprisingly states "Disassembly after drilling and before riveting, in order to deburr faying surfaces, shall not be required." It's not clear to me if this means "don't design something that requires disassembly for debur" or if it means "you don't have to disassemble anything for debur". Van's obviously does not subscribe to the latter.

Paul

 

[prkaye]

Thanks for the info guys. Just to clarify, I'm not going around adding extra rivets to my plane. A couple of times I ran into a situation where I had one rivet in a part already set, and then another rivet went bad and had to be drilled out to larger size. That's when I wondered about the deburring issue... I didn't want to drill out my good rivets just to deburr the new (enlarged) hole.

Also, there is that spot on the elevator spar to tip rib where the plans call for two hard rivets, and because of problems leading to the holes becoming elongated, I added a strip of aluminum against the flange (where the holes were getting elongated) and put two blind rivets in there instead. Vans said this was OK, but I'm getting paranoid about my elevator counterweight falling off in flight, and wonder if i should throw an extra rivet in there for added strength (between the two that are there now). There is plenty of spacing for an extra blind rivet in there.