I had to take a couple days for thinking and doing a little reading from the "Aircraft Structural Technician" book. The book is contradictory in that in one place it says gaps can form while setting rivets because the rivet fits too snugly in the hole, and in another place it states that the gaps can happen when the rivet is too loose in the hole. So I was flummoxed! I did a bit of a computer search and stumbled on the RV9 website of Paul Eastham. Out of all the RV9 websites I looked at, his was the only one that addressed the very problem I was having. His solution was to use a deep throated clamp to hold the rib to the spar instaed of relying on the clecoes. The next day I was at the airport and ran into the local tech counselor. I started to describe my problem, he said "Clamp it!". So I went to the hardware store and bought a couple of deep throated clamps and gave them a try. Night and day difference. The first image shows the clamp. It has to be deep throated to give you enough room to get the squeezer in there. Yes, I went back to the squeezer, and things went much better. Vans calls for a 4-4 rivet for these holes, and according to the Avery rivet gauge what is required is about a 4-4.5. I tried cutting down a longer rivet, but it tended to club, so went back to the 4-4s. Those set very well. Thanks to Paul for his documentation of the problem and his solution. Lunch on me if you are ever in my section of the country.
