rivet size on ribs

[Gerhard Rieger]

The rivets on all the skins overlaying each other are MS20426-4 and on the Spars MS 20246-3 AD, are the rivets on the other ribs also MS 20246-3 AD?

[nichzimmerman]

Which model are you referring to? On the 4 place, the -4 rivets are used on the skin overlaps, main spar flange to center rib flange points, and also to rivet the .032" inboard skin to the spars. -3's everywhere else.

[Gerhard Rieger]

Thanks, That exactly what I wanted to hear. The first double rib also!

[nichzimmerman]

I had to edit my response to include one more location. Where are you seeing that they are used on the whole root rib assembly? I must have missed that...

[Gerhard Rieger]

I am asking, I do not see it on the plans.

[PaulSA]

Easiest way is to get a rivet gauge and use whatever is necessary.........

[Brad Ripp]

Is the MS20426-4 an A or AD designation? I see the 20246-3 AD listed in places with the AD hardness, but nowhere can I find the -4 designation (and all supplier listings I see for the -4 is either an A or AD available) Thanks!

[Brad Ripp]

I think I see it now. Calls for AD except where otherwise noted. Which I understand now structural is always going to be the AD?

[Chris In Milwaukee]

That's correct. "AD" rivets are tempered. "A" rivets are soft. Typically used in an application where you're going to weld over them, like in your fuel tanks. You wouldn't use an "A" rivet in a structural application.