riveting question

[Joe 5428W]

Does it matter which side you put the manufactured head vs shop head? I riveted the HS 710,714 and 00001 to the front spar with manufactured heads facing aft. looking at another builders photos, mine are opposite. i don't see any clearance issues but want to make sure.
__________________
Joe Brown
Weeki Wachee, FL
RV -7A empennage ordered
Currently flying a Cherokee 150

[wirejock]

Typically manufactured head on thinnest material side but I wouldn't drill them to reverse them. They are just as strong and potential for damage isn't worth the risk.

[Joe 5428W]

Thank you Larry, that's good to know going forward.

[fl-mike]

What Larry said, and also consider access to drill out one if you mess up.

[Tommy123]

Considering how basic a question this is I would advise you to study Standard Practices references. If the plans show a rivet that is different from standard practices, follow the plans, it was done for a reason. They lost some fighters years ago because a guy at the factory installed hardware following standard practices instead of engineering drawings. When in doubt ask Vans.
Anyway, buy a copy of AC 43.13 1b

[wirejock]

No need to buy it. It's free.
https://www.faa.gov/regulations_poli...cumentID/99861

[ksdflying]

Some very good tribal knowledge (rule-of-thumbs) on this thread. And I second that AC-43-13. Must have.
Also, and I believe I read this somewhere in the vans instructions, but take notice on the drawings the rivet call outs. The way the list parts in and order give you instruction on where to insert a rivet into a hole. There is a reason for the order of listing of parts there.
Maybe I was actually told this by one of the Aero engineers at Vans. But once I learned that, that cleared up a lot of confusion.

[RV7A Flyer]

Originally Posted by wirejock

Typically manufactured head on thinnest material side

This is true, but I notice that nobody told the OP *why*...

It's because doing it this way is less likely to cause the thinner material to "curl up" or lift up away from the other part around the rivet.

Try a test or two...take some scrap metals, one thin, the other thick, and do it both ways and see what happens. You'll see that if you put the driven ("shop") head on the thin material, the material will rise up away from the substructure.

[jacoby]

Originally Posted by RV7A Flyer

This is true, but I notice that nobody told the OP *why*...

It's because doing it this way is less likely to cause the thinner material to "curl up" or lift up away from the other part around the rivet.

Try a test or two...take some scrap metals, one thin, the other thick, and do it both ways and see what happens. You'll see that if you put the driven ("shop") head on the thin material, the material will rise up away from the substructure.

Yep. Ran into this putting the rivets into the rear spar on the elevators on the -10. The ribs wanted to curl up when placing the factory head on the spar. Flipped them around and everything went well.


Also note that the MIL spec says "3.3.3.1 Head direction. Unless specified on the engineering drawing or specification, the manufactured head of the rivet shall be located on exterior surfaces."

There are times where the plans will say to put the manufactured head on a specific side.