[prkaye]

According to an old post I found on VAF forums, Vans has said that LP4-3 and LP4-4 are suitable substitutes for spots where the LE ribs attach to the spar, and it's difficult to buck hard rivets. They say the LP4-4 are used where the .125" doubler plate is on the spar. In these spots the plans call for 4-7 hard rivets. Why is it that you can use a length of -4 in a blind rivet where you would need a -7 for a hard rivet? I read the section on blind rivets in the Standard Aircraft Handbook, but still don't understand the relationships between lengths of hard and blind rivets.

 

[Mel]

The dash number on a blind rivet is the "grip" length, whereas the dash number on a solid rivet is the "overall" length.

 

[cytoxin]

overall length?

The dash number on a blind rivet is the "grip" length, whereas the dash number on a solid rivet is the "overall" length.

only overall on 426's not on 470's but then maybe you were saying overall as in just the shaft portion...

 

[Mel]

only overall on 426's not on 470's but then maybe you were saying overall as in just the shaft portion...

OK, "The length that goes through the material before smashing!"
When you measure the "overall" length of a bolt, do you include the head? I don't.
Sheesh!

 

[osxuser]

Grip... grip is the part that is in the material.

 

[Mel]

Yes, that's true, and that is what is listed with the pulled rivets. The grip length is the maximum thickness of the material to be riveted together.
Solid rivets do not list grip length. It is up to you to determine.

 

[GAHco]

Grip Length

The grip length for a solid rivet may be estimated.

To calculate the grip length for a solid rivet.

Start with the overall length, and then deduct 1.5 times the diameter of the rivet. This is its theoretical maximum grip length.

To get its theoretical minimum grip length, deduct 2.0 the diameter of the rivet from it's overall length.

I say theoretical, because there may be variation in the hole quality / diameter.

The general rule is for long rivets you will need more of the rivet extending beyond the material before setting as it will take more material to fill a longer hole with the same diameter rivet.

On Countersunk Fasteners, including rivets, the head is included in the Grip Length.

On Protruding Head Fasteners, the head is not included, rivets or otherwise.

For some general fastener measurement and terminology open this link and save for future reference. It is also in the back of our reference book.

It is worth getting just for the very practical and easy to use decimal chart near the end.

It is copyrighted, but you may use it for unlimited non commercial purposes.

It is also not openly linked on our site, so get it from here while you can, or get it later by ordering our PB REF BOOK under literature.

http://www.gen-aircraft-hardware.com/images/pdf/fastener_math.pdf

Hope this helps

 

[cytoxin]

oranges and apples

When you measure the "overall" length of a bolt, do you include the head? I don't.
Sheesh!

he was asking about rivets not bolts and yes i do include the head if it is counter sunk as this is the accepted practice.

 

[Mel]

You win!!!!

 

[GAHco]

More Oranges and Apples

Apples / Oranges, it reminds me what I have told my sales ladies concering how to handle the overly friendly and occasionally forward customers.

(just tell them) "Thank you but we sell hardware here, not SOFTware!"