Inspection criteria for rivet manufactured heads 2

[moazzam531]

Hi all,

I am trying to find out what the inspection criteria for solid rivet manufactured heads are. If we install a rivet on a cylindrical surface ( imagine a 2ft ID pipe 1/8 inch thick) the surface wouldn't be flat for the manufactured head to sit flat.
AC43-13b doesn't provide any criteria in such a situation.

is the gap under the manufactured head acceptable in this condition? if not what is acceptance criteria and the fix?

Thanks

 

[bf109g]

Hi Moazzam,

Generally, it is acceptable to have a gap between the rivet head/bucktail and a curved surface as long at the portion of the rivet which contacts the surface meets whatever standard you use for head/bucktail gapping.

If you weren't satisfied with that, you could machine an adapter (shim) to provide rivet support. Just be sure to take into account any fastener bending due to the shim.

 

[thruthefence]

If you were really concerned, simply spot face the surface lightly before the rivet is shot. I can't imagine a two foot diameter tube having curvature under a rivet head anyway.

 

[rb1957]

i 2nd that, but 1st i'd shoot some rivets to see how they look, i can see the head deforming to suit the curved skin

 

[berkshire]

moazzam531
You do not say what rivet you are using, but most rivets will conform to that slight a curvature, I second what rb1957 has said, shoot some into a sample and see what they look like, see if you ,can, get a feeler gauge under the head.
B.E.

 

[moazzam531]

Thanks for all the replies

The curvature is enough for us to stick a two thou feeler gage under the manufactured head.

 

[rb1957]

what size rivets ? in any case, 0.002" doesn't sound too significant ... i don't see this having much effect on the shear strength of the rivet, there may be some (small?) question about sealing 'round the rivet. is there a significant tension load on the rivets ? in any case, your manuals (or your customer's acceptance manuals) should specify gapping limits on rivets.

 

[WKTaylor]

moazzam531...

Check out following for solid rivet installation criteria You need...

MIL-STD-40007 RIVETS, SOLID, INSTALLATION OF

BAC5004-1 (Boeing Spec)

Both have rational discussions and examples.



Regards, Wil Taylor