7.8 Flashcards
What is the most common rivet angle
100 degrees
How can countersink be shown
26 for csk
70 for universal
AN 470 4-5
What does the 4 and the 5 denote
4 is the diameter
5 is the length
1100?.
A
Plain
Aluminium alloy
2117
AD
A dimple
Copper
5056
B
Cross
Buried
Magnesium
Prevents dissimilar corrosion
2017?.
D
Dot
Lewis gets D in 2017
Copper
2024?.
DD
Two dashes
Lewis gets double ds in 2024
Copper
7050?.
Circle
E
Engagement ring
Zinc
What should the diameter of the tail be on a tail
1.5D
What is the Land and what is it normally
Centre if rivet to edge of material
2D to 2.5D x diameter of rivet
What is the pitch and what is it normally
Distance between centre to centre if rivets in the same row
Minimum is 4D
What is the spacing and what is it normally
Distance between fastener rows from centre of holes
4D to 5D
What is the sphere of influence and what is it normally
Area of sheet metal over which a rivet will achieve a water tight seel
5D
How is the rivet size for a sheet repair determined
3 x the diameter if the thickness of the thickest sheet being joined
What rivets are cooked
2017 and 2024
How long are rivets normally cooked for and at what temperature
30-45 mins
490 degrees c
How long should you take between removing from oven and quenching and why
10 - 15 seconds
To prevent interganular corrosion
Why do we refrigerate rivets if we are not using them after quenching
To delay natural ageing process
For 2024 and 2017 how long do you have from quench to freezer
2024 - 5 mins
2017 - 30 mins
At what temperature can rivets be in a freezer for 7 days
-18 degrees c
At what temperature can rivets be in a freezer for 20 days
-20 degrees c
How many heat treatment cycles can a rivet have
No more than 2
What is the rivet spacing on a pressurised fuselage to prevent inter-rivet buckling
6D
What is the rivet spacing on a wing spacing to prevent inter-rivet buckling
3.75D for a solid rivet
4.5D for a hi- lok rivet
What are the three methods of dimpling
Coin
Radius
Hot
What method of dimpling is preferred and why
Coin dimpling
Allows for easy stacking and nesting
How do you coin dimple on hard metals
Heat up the dyes to prevent cracking, known as hot or thermal dimpling
Why do we dimple
If the skin is too thin
Causes knife edges if countersunk
What are the three methods to countersink
Pneumatic rivet gun
Hand hammer
Squeezer
What is the preferred method of riveting and why
Squeezing because it makes them all uniform is set up correctly
If a rivet head is cracked what is it caused by
Incorrect heat treatment
For a hi- lok what is the collar on an aluminium alloy rivet
Max of 3 degrees
For a hi- lok what is the collar on an CRES rivet
0.5 degrees
What is the advatange of a high lite and why
15% lighter than a high lok
Because the thread pitch run out - it only has 1
What is the advantage if a cherry max and why
You can use any tool to install it because of the driving anvil
What do you use to install a cherry lok
A specific tool to be installed
The locking collar and shear ring ensure it breaks of at the correct point
What over size is a cherry lok rivet
1/64
When do you use blind rivets
If you can’t get access to the rear
