Sheet Metal & Non-Metallic Structures Flashcards
How do you determine the total length of a solid rivet for installation?
The grip length +1.5 x the rivet diameter.
What is done with the rivet head stem when a self plugging rivet is installed?
The stem is pulled until it snaps off, and the remaining projecting part is trimmed flush with the head
Give examples of self plug-in, mechanical lock rivets
Cherry LOC and Cherry Max or Hulk LOC
What methods are used in forming sheet metal?
Shrinking, stretching, bumping, gripping, folding
What factors are used to determine setback?
Bend radius and material thickness
What calculation must be made with bending sheet metal?
Bend allowance and setback
What must be done when two bends intersect to prevent cracking?
Relief holes are drilled at the intersection or corner
What is a Joggle?
It’s the offset formed on a part to allow clearance for a sheet or another mating part
What is the purpose of lightning holes cut in rib sections?
To reduce weight and increase stiffness
Describe Rivet head markings for A, B, D, AD & DD rivets
A– are plain
B – have a cross
D – have a raised dot
AD - have a dimple
DD – double dash
What are the correct dimensions on a properly formed rivet head?
1 1/2 the shank diameter and 1/2 of the diameter height
How do you determine the proper material to be used for repair on an all metal aircraft?
Use the same type in thickness of the material that was used in the original structure
What is the single row spacing an edge distance for protruding head rivets?
Edge 2D the diameter and its spacing is 3D the diameter of the rivet head
Describe the criteria for a replacement of a 2024 rivet with a 2117 rivet for general repairs
For 5/32 or less diameter, use the next larger size rivet 2117 and the edge/spacing distance must meet the minimum requirements
What is the major type of damage to aluminum structures that is caused by exposure to the weather?
Corrosion
What is the difference between the tools required to pull Cherry Lock Rivet in a Cherry Max rivet?
Cherry LOCK - requires different pulling head for different sizes
Cherry MAX - same pulling head for different sizes
How can a mechanic determine whether the counter sink for a flush or if it should be dimpled or drilled?
By the thickness of the top sheet, thin sheets are dimpled and thick sheets may be countersunk
What action is taken to prevent cracks from forming while dimpling magnesium or some hard sheet metals?
Hot dimpling equipment is used to preheat and soften the metal before the dimple is formed
What type of damage can occur when using a rivet shank that does not properly fit the rivet?
The rivet head and sheet metal may be damaged
Why is it important to use the proper bucking bar when performing sheet metal riveting?
A bucking bar too large or heavy is difficult to control and you can damage the sheet metal. A bucking bar too light will not properly upset the rivet before work hardening occurs.
What procedures should be followed to properly remove a solid shank rivet?
Center punch the rivet and drill to the base of the rivet head usually the same size or one size smaller then use a pin punch to chip off the river head
Which of the five stresses is the most common cause of rivet failure?
Shear
