Here's a nifty little tool I modified to be able to rivet in really tight areas. I ground down the tip to make it thin enough to get into the last hole or two in a narrow rib like the rudder tips. I tried several other techniques including one on the "Hints for Homebuilders" section of the EAA website. This method is far superior to every one I tried. I also like that this was an ebay bargain. Got it for $2 plus about $5 for shipping. Can you say steal? They normally sell for about $50.