7.8 Riveting Flashcards
What is the most common countersunk angle
100 degrees
What are different rivet sizes available in
1/16 increments
What is the most common material for a rivet
Aluminium alloy
What is likewise for 2017D and 2024DD rivets
They need to be heat treated before use
What are the two phases of heat treating
Heating and soaking
Quenching
How long should the action of taking the rivet out of the oven and into the quench take
No more than 15 seconds
What must you do with a heat treated rivet to prevent its natural age hardening process if not uses straight away
Freeze them
At -18 degree C how long can you keep the rivets in a freezer for
7 days
At -20 degree C how long can you keep the rivets in a freezer for
20 days
How many heat treatment cycles are allowed in the same rivet
No more than 2
Need to get m6 rivet AD DD etc
What is a rivet pitch
From the centre of one fastener hole to the centre of the next fastener hole in a row
What is the edge margin/land edge distance
The distance from the centre of the fastener hole to the nearest edge of a sheet
What is the edge margin used for
To guide for the installation of fastener holes along the edge of the material.
(Rule of thumb is 2D to 2.5D times the diameter of the rivet)
What is spacing
The distance between fastener rows, taken from the hole centres.
(Rule of thumb - 4 to 5D)
What is it meant by the sphere of influence
The area of sheet metal over which a rivet will achieve a water tight joint.
What is it meant by the allowance
The amount of protrusion of the rivet shank that is sufficient to form the shop head (tail)
How do you prevent skin plates buckling
The maximum rivet spacing of a pressurised rivet is 6D or 18t(whichever is smaller)
What is the maximum spacing on a wing structure
3.75D (solid rivet ) or 4.5D(10t) for a hi-lok rivet
Why do we dimple skins
If the skin is too thin to countersink
What is dimpling
The skin is shaped (dented) to accept the head of the countersunk rivet
What are the three different methods of dimpling
Coin dimpling
Radius dimpling
Hot dimpling
What are the three ways that you can solid rivet
Pneumatic gun
Hand hammer
Continuous squeeze riveting
What is coin dimpling
A male die fits through a rivet hole and the coining ram in the female exerts a controlled pressure on the underside of the hole whilst the male is forced into the upper side.
This gives the hole sharply-defined edges. The top and bottom of the dimple are formed to a 100° angle, enabling dimpled skins to be stacked (or nested).
What is radius dimpling
The pilot on the male die passes through the hole and presses into the female die.
The dimple formed does not have parallel sides as the lower side has an angle greater than 100°, therefore these dimples cannot be nested.
What type of dimpling is better for tight locations
Radius dimpling
Because the equipment is smaller
What is hot dimpling
To prevent this cracking, the material is heated during the process. The equipment is similar to other ways expect the die is heated
What materials require hot dimpling
Magnesium and some of the harder aluminium alloys (such as 7075) cannot be successfully cold-dimpled, as the material is so brittle that cracks will form during the process.
What prince of equipment do you use with a rivet gun for reaction riveting
Back up dolly or a bucking bar
What is another word for hand riveting
Percussion riveting
Why when hand riveting do you want to do a minimal blows as possible
Because If you do a lot then you might work harden the rivet
What is the preferred method of riveting
Squeezing method
What is the squeezing rivet method
Makes the upset head in a single continuous action.
A viable in hydraulic or pneumatic
When using a mircrostop countersink tool what must you prevent it from doing
Rotating else it may cause surface damage
What are the optimum and maximum timing to form an upset head
3-4 seconds optimum time
7 seconds maximum
What tool can be used to flush countersunk rivets down by shaving them
A mircroshaver
Cracks in certain rivet heads are not allowed - what material is this
Monel and titanium
What is the main source of structural fatigue and failure
Fastener holes
What is grip length
When determining the length of a fastener for installation, the combined thickness of the material to be joined must be known. This is the grip length
How do you work out the grip length
You use a grip length
- put the grip scale in the hole
-hook the gauge onto the rear face of the material
- then read the material thickness on the front of the gauge
What is a Jo-bolt
A high tensile steel blind rivet which is installed with a ratchet hand tool
What is another way to describe the installation of a jo bolt
To set it
When using a Jo bolt do you have to mill down the excess to make it flush
No, with a jo built the bolt breaks at the waisted part when at a set torque. The spring loaded plumber in the tool ejects the unwanted bit.
Which way is the torque for a jo bolt applied
In a counter clockwise direction
How do you remove a jo bolt
By a drill
What does an additional drive nut on a flush fastener head allow
Have small recesses to allow seating torque to be checked in installed fasteners
How does visu lok II prevent FOD
The drive nut stays on the discarded pintail after installation
(Also steel nut is magnetic so easier retrieval)
What are the two parts of a hi-lok and hi-lite fastener
- A threaded pin with a head (universal or countersunk)
- A collar with an internal thread and an external groove
What process is use to harden solid rivets after solution heat treatment
Age hardening
Solid rivets may be solution treated as many time to save wasting them - true or false
False only twice
What angle countersinks are available and which is the most common
82,100, 120
Most common 100
Which rivets require heat treatment and how many times can they be treated?
2017 D-, 2024 DD- and 7050 E are brittle and hard so need heat treating
One further cook is allowed before installation but after that rivets have to be discarded
If rivets are not used after heat treatment how long can they be kept for and how can this be extended
What dimpling process provides sharply defined edges
Coin dimpling, allows for stacking or nesting of skins
How is depth adjusted on a microstop countersink tool
By pulling the sleeve back and turning the stop to increase or declares the cut. Then dropped back into its original position.
Is cracking around the tail of an AD rivet acceptable when installing solid rivets
No, but is allowed with 2017 and 2024 rivets within limits of SRM
Are cracks in the head of a Monel and titanium rivet permitted
No.
What is an advantage of a hi- lite
Reduced weight, shorter
Where do you use cherrymax rivets
High vibration areas
Where do you use cherry lock rivets
Both thick and thin job items
Before you install a blind rivet what hole prep must you do
Clean
No burrs
Not damaged
What hole prep must you do before inserting a blind rivet
Clean
No burrs
Not damaged
