Evaluating Rivet lengths

RVG8tor · #1 12-27-2007, 09:49 PM

So far I have just followed the call out in the plans for rivet sizes. I have only done my VS os far and I am working on HS today. Today I riveted on the 413 hinges to the HS rear spar. They call for AN470 4-5 rivets. I set them and they looked too tall, just over the .07 max height of the Mil spec. They look like little muffins. I searched this site for rivet size information and learned a lot but wondered how often builder stray from the plans. I don't want to build any slower than I am already, so far I just want to stick to the plans but these shop heads are really tall. They are are set nicely not clench or anything, although I think one cracked. I will have to look at that one with some magnification. Should I drill them out and replace with shorter rivets or do I leave well enough alone and just live the the tall heads? I know what can happen with drilling out rivet, it can make the situation worse.

Any advice would be appreciated. I stopped with the left side hinges until I can decide if I should continue with the longer rivets.

Cheers
Mike

Transporter · #2 12-27-2007, 11:04 PM

Mike,
I checked rivet length before driving/squeezing. In a couple of cases I used a rivet cutter to cut some 'custom' rivet lengths. In general I was satisfied with Van's rivet call outs.

I'd ask yourself whether a given rivet will be strong or weak. Obviously, you want to keep the strong ones and get rid of the weak ones. A rivet that's well-formed (good shop head, proper diameter, etc.) but is a little tall will still be a strong rivet and I'd keep it. The big danger with a rivet that is too long before driving is that the shop head will clinch/deform so if it hasn't deformed it will be fine.

If you've got a bad rivet (clinched over with a thin shop head on one side, cracked, etc.) then obviously you should fix it.

Consider marking rivets you're not happy with using a Sharpie as you rivet. If they still look bad to you the next day, do them over or get a second opinion. They won't get any worse over night-but don't build so far that you can't get to them the next day!

Good luck!

penguin · #3 12-28-2007, 01:10 AM

There's no need to drill out any rivets that are not cracked. As long as the tail achieves the min height and width its good. The issue with using rivets that are too long is that its much easier to put the tail into shear and/or crack it. If the tail sets properly without cracking then carry on. I found there are some call outs that were too short. Making "custom" length rivets is rather extreme! If a size shorter is too short then you have to use the next length up, it really quite straight forward.

Pete
RV-4, 6A & 7