7.8 Flashcards
What must 2017 (D) and 2024 (DD) rivets be before use?
Solution heat treated.
Partially softens material and prevents cracking
What soak temperature are rivets heated to?
495 Celsius (+-5)
923 Fahrenheit
What’s the maximum elapsed time for the transfer of rivets to the quench tank?
15 seconds.
Why must rivets be refrigerated after heat treatment?
To delay the natural ageing process.
What should the time not exceed between quenching to refrigeration of rivets?
2017 rivets= 30 minutes.
2024= 5 minutes
Prior to refrigeration, what are heated rivets immersed in?
Isopropyl or ethyl alcohol at -20 Celsius or lower to remove water.
How long can heated rivets be stored for?
7 days at -18 Celsius
20 days at -20 Celsius
What’s the maximum number of heat cycles that can be performed on one rivet?
2
How much bigger is a hole normally drilled than the rivet shank diameter?
0.1mm
What does AN mean in terms of rivets?
Air Force Navy.
What is the distance for PITCH for rivets?
4D
What is the distance for SPACING for rivets?
4-5D
What is the distance for EDGE MARGINS/LAND for rivets?
2-2.5D
What distance is the SPHERE OF INFLUENCE for rivets?
5D
What does the sphere of influence do for rivets?
Provides water tight joint.
What is the allowance for a rivet?
The amount of protrusion of the rivet tail that is sufficient to form the shop head.
What book is used for quick conversion?
Zeus book
What’s the maximum permissible rivet spacing of a pressurised fuselage?
6D or 18T
What’s the maximum rivet spacing of the wing structure for solid rivets?
3.75D
What’s the maximum rivet spacing of the wing structure for hi-lok rivets?
4.5D or 10T
Whichever is smaller
When is dimpling performed?
If the skin is too thin to countersink.
What does coin dimpling do?
Gives the hole sharply defined edges.
100 degree angle, enabling skins to be stacked (nested)
What does radius dimpling do?
Dimples formed do not have parallel sides, angle greater than 100 degrees.
Cannot be nested.
What dimpling is used to tight locations?
Radius
What material are hot dimpled?
Magnesium and some other hard aluminium alloys (7075)
Too brittle and can crack.
What are the 3 riveting methods?
Pneumatic gun
Hand hammering
Continuous squeeze riveting
What is it called when a bucking bar is used to form an upset head?
Reaction riveting.
What is the rivet set called which goes into the end of the rivet gun?
Rivet snap.
What is hand hammering riveting also known as?
Percussion riveting.
What do too many hammers on a rivet do when hand hammering?
Work hardens the rivet.
What depth defects are acceptable on rivets?
Up to 0.10mm.
What is the preferred method of riveting?
Squeeze.
What is the hand method primarily used for?
Small repairs that include very few rivets.
What is the optimum and maximum time for the formation of rivets?
3-4 seconds optimum
7 seconds maximum
What would a large number of cracks in a high percentage of rivets indicate?
The rivets have not been heat treated correctly.
What would be used to achieve a flush surface on a countersink rivet?
A microshaver.
What is the measurement for the combined thickness of materials to be joined?
The grip length.
What are 3 of the grip gauges?
Hi-Shear
Visu-Lok
Cherry
What is a Jo-Bolt?
A high tensile steel, blind fastener.
What head shape is on a Jo-Bolt?
Hexagon.
What tool is a Jo-Bolt installed with?
Ratchet hand tool.
What can only be used to remove a Jo-Bolt?
A drill.
What is a more advanced version of a Jo-Bolt?
Visu-Lok II
On standard Hi-Lok steel nuts, what is necessary when the outer surfaces on wings are more than 0.5 degrees out of parallel?
Spotfacing.
On what Hi-Lok collars are an out of parallel condition of up to 3 degrees acceptable?
Standard aluminium alloy.
How many degrees out of parallel is acceptable for Hi-Lok CRES collars?
0.5 degrees.
How much lighter is a Hi-Lite fastener than a Hi-Lok?
Up to 15%
What is the maximum run out all standard thread length pins require?
2 pitch.
What makes a Hi-lite fastener lighter?
Shorter thread.
What type of rivets are Cherrylock and Cherrymax?
Blind rivets.
Where are cherrymax rivets effectively used?
Thin items or high vibration areas.
What FOD is there when installing cherrymax rivets?
Driving anvil.
Is there a driving anvil on a cherrylock?
No.
