Drilling out rudder/stiffner rivets?

[gbumga]

Hi, I have tried every technique I know to drill these little suckers out without damaging the dimpled skin. Some are ok but some enlarge the dimpled hole. I have been practicing on a bad skin and I can't get a whole row done without screwing up a couple. This problem is because the stiffners were a little long and wouldn't let the R-902 spar lineup correctly. I put a thin alum. piece under the stiffners and used a drimel tool to take the excess off, it left the stiffner end impossible to cleanup and I cut to much off 5 stiffners [3, 1/32 to short,2, 1/16 to short, min. edge distance] and want to replace the stiffners but can't drill em out good. these parts aren't expensive and put together fast but I'd rather just replace 5 stiffners if i can get them drilled out right. How the heck do you guys do this? Gene

[N941WR]

Gene,

Check out this thread:
http://www.vansairforce.com/communit...ead.php?t=8481

[zilik]

1. start on the manufactured head and using a #41 or 42 bit drill through the head only as deep as the rivet head. DO NOT drill till the drill goes through the rivet. If your having problems getting the drill to center on the rivet head twist the drill a couple of times by hand before giving start of drilling. (Always a good practice anyway)

2. Using a 3/32" pin punch or the wrong end of a #40 drill snap the rivet head off by inserting the drill or punch into the drilled hole and push the punch sideways to pop the head off.

3. On the other side is the shop head (the one you made). Grind down a pair of diaginal cutters so that the cutting edge is flush on one side. Act like your going to snip off the shop head and the the rest of the rivet will pop out.

4. No damage to the hole.

If you drill all the way through the rivet you'll end up with more oblong holes than round ones.