Rivet Size Question...

[s10sakota]

OK, this is probably a dumb question, but am I using this rivet size gauge correctly?



Just for this picture I grabbed any rivet off the bench but as shown here it is way too long right? I believe the idea is to insert a rivet, and then it should fit nicely into the cutout?

If this is the case, then the plans are calling for rivets that are too short for the bottom pieces.

I am riveting the R-710 Horn Brace to the spar (with the little spacer inbetween). As you can see in the pic of the plans, it is saying to use AN470AD4-7 rivets. Those are too short. The 4-8 that I stole from another bag of rivets work perfect.



So now I'm wondering if after selling 7,000 kits Vans hasn't figured this out or am I some kind of genious and I'm the first to find this?

Oh please tell me I are really smart!!

Seriously, since I am totally new to RV building I just want to make sure that I'm doing this correctly.

And since I'm here, I will ask one more question... Before I realized the rivet was too short, I pounded it in. It looked good too! But since the shop head was too small I drilled it out and made the hole large enough where the new rivet will wiggle around when I insert it. So, I need my first 'oops' rivet. How do I know what size oops rivet to order? ANd how do I know how much wiggle (if any at all?) is OK?

Is there a chart somewhere with a a list of rivet sizes and their corresponding oops rivet size?

pic here...http://www.aircraftstickers.com/RV7A/1nov11.htm

[TomNativeNewYorker]

OK, this is probably a dumb question, but am I using this rivet size gauge correctly?

I never used a gauge, but I would venture to guess it would be correct. Once you do enough riveting, you will be able to tell just by looking if the rivet you stick in the hole is too short or long.

And since I'm here, I will ask one more question... Before I realized the rivet was too short, I pounded it in. It looked good too! But since the shop head was too small I drilled it out and made the hole large enough where the new rivet will wiggle around when I insert it. So, I need my first 'oops' rivet. How do I know what size oops rivet to order? ANd how do I know how much wiggle (if any at all?) is OK?

Is there a chart somewhere with a a list of rivet sizes and their corresponding oops rivet size?

If you have a defective rivet the proper way to remove it so you do not elongate or oversize the hole is to drill the 1/8" rivet with a number 30 bit dead center. If you have trouble with getting center, start with a #40 and then go up. You only need to drill deep as the depth of the rivet head. Then you take a 1/8" drift punch and put in the head you just drilled and work it so you can pry/snap the head off. Then you should be able to drive the remainder of the rivet out with the punch and a hammer. If the material is thin, get someone to hold a scrap piece of wood on the back side next to the rivet you are driving out to support the metal and prevent damaging it.

[TomNativeNewYorker]

Is there a chart somewhere with a a list of rivet sizes and their corresponding oops rivet size?

Example: You installed a MS20426AD4-5 countersunk rivet that for whatever reason you had to remove and you blew out the hole. The next diameter is 5/32" if the material is thin and you can not counter sink the metal deeper what you would do is use a #21 drill bit on that hole. You would use a NAS1097AD5-5 rivet as a replacement. The head is a reduced size countersink, mainly used for thinner metal where you do not want to remove excessive amounts for countersinking a rivet hole. The 5/32" 1097 rivet is the same size head as the 1/8" 426 head so no other processing of the countersinking is needed.

For most of the rivetbangers here, they use the oops rivet for aesthetic purposes so they do not have one larger rivet head in a row of rivets. If you blow out a buttonhead rivet head hole, you cant get away form the mismatched look when you step up to the next diameter rivet.

[captain_john]

Mark, I have that very same gauge and you ARE using it wrong.

You measure the rivet using the gauge 90 degrees counterclockwise. (the other dim is the one you use to gauge length).

It is a very good gauge and will serve you well.

Does this help?

CJ

[lgcdmb]

You can use a scale to determine what edge of the gauge to use. The length is in 16ths, so a 3-4 rivet is 4/16 (1/4) in. long. The length is measured from the surface of what you're riveting so you measure from the flat base of the dome on a 470 (universal head) rivet and from the top of a 426 (flush) rivet. I keep all of my rivets separated so the rare instance when I need to measure one I either compare it to a known rivet or measure with a scale. I can't remember ever using the gauge. Assume that the rivet callouts on the drawings are right. If the rivet lengths seem off, the first thing to do is make sure you have the right rivet and that all pieces are fitting together properly with no burrs or chips holding pieces apart.

As mentioned above, when drilling out a bad rivet, use a drill the same size as the rivet shank only as deep as the head (flush or universal) and pop the head off with a punch or even the back end of the drill. I then frequently drill down thru the rivet with a drill that is a 32nd undersize and it pops out on its own as I'm drilling with no damage to the surrounding metal as long as you're on center.

The need for an oversize or oops flush rivet is a judgment call. The best practice is to be as careful as possible when drilling out a rivet to avoid enlarging the hole. The shank of the rivet does expand to fill the clearance space when setting the rivet so it will fill in a hole that is slightly oversize. How much is something that you'll get lots of opinions on, but let experience guide you.

When you start out, you want everything to be perfect. As you get further into the project, you'll find that sometimes your efforts to drill out and replace a less than perfect rivet leaves you with something that is worse than what you started with. If it's structurally good enough, consider moving on. There's a significant engineering safety factor built into the design so a less that perfect shop head here and there won't cause your RV to fall from the sky.

[s10sakota]

Thanks everyone. I'm learning a lot just from this thread!

The pieces that I am riveting are all deburred and fit together nicely. The pieces do have an extraordinarily thin coat of Zinc Chromate primer but if I use the 4-7 rivet the plans call for, I can not get the shop head large enough which tells me the rivet is too short.

I am sure it's the correct rivet because I took it right of the bag marked "4-7".

I'll double check everything just to be sure.

Thanks again!

[Wicked Stick]

Mark,

There often are instances in the rivet call outs that are sometimes a little shorter than optimal. This makes it easier to buck a proper head on it, but does sometimes leave it too thin.

I would suggest purchasing a few different 1/2 size bags of rivets to have on hand so you end up with the correct length. If it's only a few rivets here and there, you can use the next size up and cut a little off using a rivet cutter as another option.

I found it's best to have a 1/4 lb. of 426-3.5, 4.5 & 5.5's handy when I built my 8. Their not very expensive items and really save a lot of time and you get the perfect shop head with the correct length starting out.