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How to drill out rivet behind skin

Fugitive

Member
I have a cracked aft bulkhead and have filled out all the rivets but the one behind the skin where the red circle is. How should this be achieved? Thanks in advance. IMG_3190.jpeg
 

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I would come at it from inside and go ahead and drill right through that skin as you're going to have to rivet it back in place anyway, right? Although I don't completely understand the rivet pattern there, which airframe is this?
 
Can you drill out the aft rivet, and peel back the skin a little, to me looks like the rivet should be there, don't know why it was done underneath. Don't you need to take out the next vertical rivet line as well, for the other side of the bulkhead? With that drilled out, I would guess you can peel the skin back enough to at least see what you're working with better.
 
Can you drill out the aft rivet, and peel back the skin a little, to me looks like the rivet should be there, don't know why it was done underneath. Don't you need to take out the next vertical rivet line as well, for the other side of the bulkhead? With that drilled out, I would guess you can peel the skin back enough to at least see what you're working with better.
So far the forward bulkhead looks good and my plan is remove after bulk head and inspect. If forward is cracked, obviously I’d replace. But if it’s sound I was planning on just replacing after bulkhead. I ordered two, one was sent and the other is on backorder.
 
Get a center drill slightly under the hole size. Centerpunch dead center on the shop head. Angle drill into the shop head center using the center drill just enough to create a good pilot hole at dead center of the rivet. Drill with a twist drill using that pilot hole until just even with the plane of the skin on the inside. Break the shop head off with a punch of appropriate size. This should give you a clear view of the unenlarged hole in the skin from inside. See if the manufactured head can be knocked out with that punch while backing the outside skin to prevent creating a convex dent around the hole on the outside of the skin.. If not, use a slightly undersize drill on the center of that hole and relieve the manufacture head on dead center. Retry the punch while backing the outside skin. That should do it. Avoid enlarging the hole to the maximum of your ability. Good luck.

(The center drill does not wander when you put its tip on a spot, especially if it is already punched with a center punch. I drill out rivets this way and a lot of times I am able to hit the hole perfectly centered causing the rivet to fall out of the hole without punching or enlarging the hole. Using the center drill to create a pilot hole, practice drilling out rivets from both manufactured and shop head sides. I predict you will fall in love with this technique. YMMV.)
 
I agree with rsultzbach above if I was saving the bulkhead. Since that's scrap, I would grind the shop head flush and cut that portion of the bulkhead. The rest should come out and leave a small piece easily removed. Once clear, you can decide how to address the oddball rivet on each side.
 
The shop head can be ground off, as mentioned above, so that the scrapped bulkhead may be removed. The rivet with its factory head under the skin was required during construction to hold the bulkhead in place on the jig before fitting the skins (standard practice for slow build RV-6).
If you were to drill out the shank of the rivet, through both the longeron and the outside skin, it will leave behind the factory head in the longeron beneath the skin. The replacement rivet for attaching the new bulkhead to the longeron could be an "oops" flush rivet (small head) machine countersunk into the .025 skin, or a universal head rivet (which won't be noticeable in that location).
 
You shouldn't have to grind it off might even be harder. If the shop head is drilled center it will likely snap off just like the other side would. I'd try that first with an angle drill and then if that didn't work grind it.
 
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