7.8: Riveting Flashcards
What are three types of rivet joints?
Lap joints
Flush joints
Joggle joints
What are the factors that govern strength in a joint?
Material specification
Rivet specification
Rivet spacing
What are lap joints?
When the skin is riveted together so there is a distinct change in levels
What are joggle joints?
A combination of flush and lap, with one skin joggled to accomodate the other producing one smooth side
Where are lap joints usually used and why?
On light aircraft where aerodynamics aren’t as critical
What are joggle joints used for?
As doublers over internal structures, by allowing the pieces of metal to be on the same plane
What is the pitch of the fastener?
- The distance from the centre of one fastener hole to the centre of the next fastener hole in the same row
- Quoted in terms of fastener nominal shank diameter D
- horizontal
What is edge margin/land?
The distance from the centre of the fastener hole to the nearest edge of a sheet
What is the general rule of thumb for edge margin in terms of D?
2 to 2.5D
What is spacing? What is its usual dimension?
- The difference between fastener centre holes between two different rows
- generally 4 to 5D
- vertical
What are spheres of influence? What size is it usually?
The area of sheet metal that a rivet achieves a watertight joint, usually 5D
What pressure do pneumatic guns operate at?
92 to 99 psi
How much blows per minute do slow hitting rivet guns do?
900 to 2500 bpm
How quick does a rivet gun upset a rivet?
one to three seconds
How should the force of the rivet gun be absorbed?
By the bucking bar
What are larger rivet heads used for?
Thinner skins
When can compression riveting be used?
Where the reach of the riveting tongs is long enough
What are the two types of compression riveting?
Hand held riveting
Pneumatic riveting
What are the common skin pins?
Cleco fasteners
Gripper pins
How much force does cleco wing nut fasteners use for clamping?
135 kg of clamping force, making them useful for higher clamp up pressure
Do gripper pins need tools?
No unlike cleco
How is the depth of a cut adjusted on rivet shavers?
By pulling outwards on the stop and turning it in either direction
What are countersink tool angles?
82 degrees
100 degrees (most commonly used)
120 degrees
What’s the most common problem encountered when hand countersinking?
chattering
What size should the pilot in microstop countersinking be?
Should be 0.002m in smaller than the hole size
When is dimpling is materials used?
When they are too thin to countersink directly
Where can you find rivet spacing, edge margin and pitch minimums?
Structure repair manual
