[ditch]

Just want to get a feel for what people think the reason for de-burring holes is. Often after final drilling holes, I can't feel any real burr or lip around the holes. Is the purpose to knock down the bigger chunks that sometimes seem to hang up on the holes or is to break the edges of the holes even if there isn't a burr there? I have a really hard time de-burring holes when they feel fine and look fine. Unless the reason is for breaking the edges of the holes, do you really need to do it to each hole? How many do each side of the holes? Just curious cause this has been making wonder for some time now. I have been doing any hole that feels slightly rough but not every one.

 

[LettersFromFlyoverCountry]

I'm basically breaking the edge. And yeah, I do both sides. A couple of turns, flip, a couple more turns. Done.

I've read some article somewhere that says this is pointless. But I figure the folks who design airplanes are smarter than I am -- at least in matters of building airplanes.

Over the course of 1700 hours I've put in on the project so far, deburring has probably accounted for about... I'd guess... 2.

 

[Les Dial]

Breaking the edge eliminates the sharp corner. Sharp corners are potential stress risers and therefore good places for cracks to start. I used to work in C-5B production. That plane had 7 million holes (really). they all had to be deburred!

 

[Phil]

I'm not a plane building expert, but I have stayed at a Holiday Inn Express before.

I debur for two reasons.

1) Preventing stress risers that develop into cracks.
2) Preventing future opportunities for corrosion to set in.

It's pretty much a given that any sharp 90 degree turn is bad. Doesn't matter if it's the edge of a thick doubler or the inside edge of a very cleanly drilled hole.

Even though there isn't a burr and the hole is perfect, it's also got a perfect 90 degree angle.

I deburr both sides. Just 1.5 - 2 turns. It's just enough to knock that 90 degree sharp edge off.

Phil

Edit: (Looks like Les beat me to it.)