Rivet Gauge

mhilderbrand · Post by **mhilderbrand** » Sat Nov 10, 2007 10:23 pm

Hi there,
I have been "lurking" here for a couple months but ran into a problem that requires the experts, RV builders!

Not on an RV, but I am setting -5 rivets into a Main Spar and was questioning myself using the Avery Rivet Gauge. I understand that the "roundness" of the shop end should be a little bigger than the hole in the gauge. But on the rivet height I am wondering if maybe I am over driving them?

I am poor at describing things, but here we go... what I am seeing is that the guage will slide over the rivet (shop head) but IS raised very slightly because once over the rivet head, the gauge slightly drops back onto the surface.. Some of my shop heads are not equal causing part of the head to probably be above the gauge while part of the rivet is to low, or over-driven.

I am looking for ideas or suggestions whether I should make sure ALL of the shop head is not too low, or is it really that big of an issue? I feel that I am bugging my EAA Tech counslor too much with these small questions

Thanks, so much!

Michael
Kansas

smithhb · Post by **smithhb** » Sat Nov 10, 2007 10:33 pm

Michael,

If the height of the shop head is not high enough but the diameter is correct, you just need to use a longer rivet.

Bret Smith
RV-9A N16BL
Blue Ridge, Ga
www.FlightInnovations.com

From: RB Lists - General Construction [mailto:support@rivetbangers.com]
Sent: Saturday, November 10, 2007 10:24 PM
To: generalconstruction@rivetbangers.com
Subject: Rivet Gauge

Hi there,
I have been "lurking" here for a couple months but ran into a problem that requires the experts, RV builders!

Not on an RV, but I am setting -5 rivets into a Main Spar and was questioning myself using the Avery Rivet Gauge. I understand that the "roundness" of the shop end should be a little bigger than the hole in the gauge. But on the rivet height I am wondering if maybe I am over driving them?

I am poor at describing things, but here we go... what I am seeing is that the guage will slide over the rivet (shop head) but IS raised very slightly because once over the rivet head, the gauge slightly drops back onto the surface.. Some of my shop heads are not equal causing part of the head to probably be above the gauge while part of the rivet is to low, or over-driven.

I am looking for ideas or suggestions whether I should make sure ALL of the shop head is not too low, or is it really that big of an issue? I feel that I am bugging my EAA Tech counslor too much with these small questions

Thanks, so much!

Michael
Kansas

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captain_john · Post by **captain_john** » Sun Nov 11, 2007 7:44 am

Michael,

I consider the gauge a "no-go" tool. If you actually start measuring things, I think you will find that the tool can actually slip over the shop head and be legal. There is some room for play there.

I don't like the gauge to fit around the ring side or under the height measurement. Hence, a no-go.

With regard to uneven shop heads, well they should be as even as possible according to standards. The slanted heads can be hit once again to straighten them out, so long as it doesn't "overdrive" them too much. If they are only 5 degrees out of kilter, I would leave them.

Does this help?

CJ

JohnR · Post by **JohnR** » Sun Nov 11, 2007 10:05 am

Welcome aboard Michael!

Look like the answers above should help on the shop head question. I would concur with CJ on the use of the gauge.

What you building?

mhilderbrand · Post by **mhilderbrand** » Sun Nov 11, 2007 4:05 pm

If the height of the shop head is not high enough but the diameter is correct, you just need to use a longer rivet.

The diameter is WAY within specs.. I just keep pounding away until the height is even with the gauge. Maybe I should just stop and leave the shop head high enough the gauge just will NOT go over it?

I don't like the gauge to fit around the ring side or under the height measurement. Hence, a no-go.

Pic speaks a thousand words would you call these a "no-go?" :

What you building?

Do I dare say a Sonex

Wicked Stick · Post by **Wicked Stick** » Sun Nov 11, 2007 7:56 pm

The gauge is to judge a perfectly driven rivet. If you can't fit it in the hole, and you can't slide it over the rivet, then it's within the properly driven range. If you start off however, with a rivet length that is slightly too short, you will have trouble trying to stay within the driven gauge's specs. How is the rivet length before you drive it when you check it to the other gauge?

Most knowlegable people I know say it's better to be slightly overdriven, than to be underdriven. Judging by the pictures you posted, they look fine to me... Build on...

smithhb · Post by **smithhb** » Sun Nov 11, 2007 8:16 pm

I still say use the next half-size longer rivet... This is the spar, make it right.

captain_john · Post by **captain_john** » Mon Nov 12, 2007 5:58 am

Michael, you DO dare say Sonex! You are welcome here with a plane like that!

Those rivets are keepers in my book, but like Bret says... if you can make em taller, do it. Personally, I would leave those but if you have more to do try making the shop head taller.

To do this, you may need a 1/2 size bigger like Bret said. If you don't have a rivet that size, polish down a longer one on your Scotchbrite wheel to make one. If you don't have a Scotchbrite wheel, GET ONE!

TIP: Make the side you cut perfectly perpendicular, otherwise it WILL NOT drive straight.

When you are done driving, it will be checked again for height and diameter.

The slant is acceptable in my book as well.

I would fly in that plane with you!

CJ

captain_john · Post by **captain_john** » Mon Nov 12, 2007 6:01 am

BTW, I checked the Van's factory spar rivets and they look just like yours.

...if that makes you feel any better!

CJ

mhilderbrand · Post by **mhilderbrand** » Mon Nov 12, 2007 2:50 pm

Thanks EVERYONE! You guys are a very welcoming bunch. I will pound some more rivets tonight

leaving the shop head a little taller. Like I said before, it will be no problem doing this and being well within diameter specs.

You guys ROCK

JohnR · Post by **JohnR** » Mon Nov 12, 2007 7:34 pm

Michael,

I have a friend who has a Sonex. They are nice airplanes. He has had it on display at Osh the last two or three years.

He has a website at http://n36sx.wheelsup.org/

I'm not sure if he updates it and keeps it current but I'm sure if you had questions he would be glad to help out if he could.

Keep us informed on your progress!

az_gila · Post by **az_gila** » Tue Nov 13, 2007 8:53 pm

No-one has mentioned the actual specifications for what makes an acceptable rivet....

The Avery tool just defines a "perfect" 1.5D x 0.5D rivet head.

Use the specifications here to check any suspect rivets. If they are within the measurements, leave them... they would be good for the Air Force, Navy, NASA, etc...

The numbers are here on my website...

http://home.earthlink.net/~gilalex/

... the numbers even work for a Sonex....

gil A

Lorin Dueck · Post by **Lorin Dueck** » Tue Nov 13, 2007 9:37 pm

Hi Michael -
Welcome!!

I hope you'll find this site (and the contributors a great help!).
I know I have.

All -
I can't remember where I saw it - but a couple of years ago there was a technical paper on joint strength vs. over, under & properly driven rivets. It looked at shear, tear, and peel strength.
Without finding it - I recall that an over driven rivet has almost the same strength as a properly driven one.
Not so much for under driven ones.
My motto - when in doubt - bang it one more time!

Lorin D
9A Wings (SB)
N194LD reserved

smithhb · Post by **smithhb** » Tue Nov 13, 2007 9:39 pm

Gil,

It's good to see that you are monitoring this Forum. Your insights are appreciated!

mhilderbrand · Post by **mhilderbrand** » Wed Nov 14, 2007 2:18 am

Thanks for the link gil, very informative!!

I can't remember where I saw it - but a couple of years ago there was a technical paper on joint strength vs. over, under & properly driven rivets. It looked at shear, tear, and peel strength.
Without finding it - I recall that an over driven rivet has almost the same strength as a properly driven one.

I just read an article like that a few days ago while searching about riveting specs. It also was comparing the strength with regards to a dimpled/countersunk joint and one without.
Thanks again,
mike

Lorin Dueck · Post by **Lorin Dueck** » Wed Nov 14, 2007 4:22 pm

Mike -

Yup that was the article I was thinking about

I just didn't want to complicate this thread which skin prep stuff (dimple / CS vs. flat).

Thx, Lorin D

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