Degree countersink #10 screws

[Brettc]

Having trouble finding this answer.. Which countersink do I need for the #10 screws on the rudder? Is it 82 degrees, or a 100 degree rivet countersink? On that note, what would the 130/120 countersink so be needed for?

[Lars]

Originally Posted by Brettc

Having trouble finding this answer.. Which countersink do I need for the #10 screws on the rudder? Is it 82 degrees, or a 100 degree rivet countersink? On that note, what would the 130/120 countersink so be needed for?

The #10 screws have 100 degree heads, the countersunk pulled rivets used on our RVs typically have 120 degree countersunk heads, though in the latter case I believe Vans mentions just using a 100 degree dimple or cutter for them, in the build instructions.

[Brettc]

Thanks!!! Placing an order then.

[jimgreen]

AN426 rivets have a 100 degree head.
From our bible:

"e. Countersunk head rivets MS20426
(supersedes AN426 100-degree) are used on the exterior surfaces of aircraft to provide a smooth aerodynamic surface, and in other ap- plications where a smooth finish is desired. The 100-degree countersunk head has been adopted as the standard in the United States."

You might be thinking of pulled rivets.

[bcondrey]

The only "oddball" countersink on the Van's aircraft is for the CS4-4 pulled, countersunk rivets. Those are 120 degrees.

[Mel]

"AN" solid rivets and "AN" screws have 100? heads.
Pulled rivets typically have 120? heads.
Non-aircraft screws typically have 82? heads.

[Brettc]

Originally Posted by Mel

"AN" solid rivets and "AN" screws have 100? heads.
Pulled rivets typically have 120? heads.
Non-aircraft screws typically have 82? heads.

Thanks! I was lookin in the manual before I ordered a countersink. Yard store has like 4 different degrees of the same countersink. I appreciate the help

[Lars]

Argh. I should type what I'm thinking, instead of what my fingers were saying. "Countersunk pulled rivets" is what I meant. Previous post edited.