Tight fitting rivets...

Just looking for a general opinion out there. Some of the rib to rivets on my 9 have been a bit tight going in (the longer rivets especially). I've had to push them a little with the rivet gun using really light taps to get them through and they go. Is this an acceptable practice?

That's fine you'll find this several times of the two holes are not lined up perfectly especially when you put stuff together and then take it apart the clecoed are not an exact fit. You can use a awl to help line up the holes. Make sure you have cleco' in at least every other 2 holes minimum to help line up the parts.

Maybe ....

Did you de-burr each hole in the stack of each skin layer?

Another trick is to wriggle the cleco next to the hole in a circular motion while inserting the rivet.

However, if the rivet does not go in with light taps, don't force it (you may be pushing the underlying surface away). Invest in a hand reamer in #30 and #40 sizes and only ream where necessary. As Mel said, try working the cleco closest to the rivet first.

Somewhat along the same lines...

How much force is too much when aligning parts for rivet insertion?

Specifically I have noticed the parts and sub assemblies seem to have the holes line up almost perfectly...but not PERFECTLY. So, I have had to force the holes to line up...they do line up just fine with clecos in place, maybe required a pound or few to pus them in place, and they don't wiggle when clecos are in place. I was just thinking I would end up like OP and have a little hard time getting rivet in place, plus then there would be "residual" stress in there?

I've got a small prick punch that I use as an awl to wiggle holes into alignment. If that isn't enough I step back and think about options. I'd be careful "tapping" it in with the rivet gun. Wouldn't be hard at all to damage either the hole or the rivet. You may scrape a stress riser into the hole and not even notice.

The awl almost always works. It's part of my standard grab of tools when it's time to pound rivets.

Never really had that problem as I recall

You will develop good skills and judgement as you go and your sensitivity may be greater than mine. I personally would be very reluctant to use the rivet gun to complete the insertion of the rivets. Too many things can go wrong. I would develop another method - maybe a stick to push in ones that don't want to be a part of your airplane. I did deburr all holes on both surfaces of every piece in the assembly - that can be a problem. Rivets have a nice rounded edge to help with the insertion when I cut rivets and install them I lose that and then the job is a little more tedious.

Since Jeanine and I started building our RV-6A in 1996 I have gone through a LARGE box and a half of "ice cream sticks" bought from Hobby Lobby and similar craft stores. They can be be used as is or modified for use as tools in this and many other applications. They are hard enought to do many jobs with low skin damage risk.

Bob Axsom