Sheet Metal Structures Flashcards
What is the major type of damage to aluminum structures that is caused by exposure to the weather?
Corrosion.
Name several methods for forming sheet metal.
Bending or folding.
Stretching.
Shrinking.
Bumping.
Crimping.
What are the dimensions of a properly formed rivet head?
1.5 times the shank diameter in width.
1/2 the shank diameter in height.
Describe the markings, found on the heads of:
A, B, D, AD, and DD rivets.
A = Plain
B = Cross
D = Raised Dot
AD = A Dimple
DD = Double Dash
What happens to the stem of a self plugging rivet when the rivet is installed?
The stem is pulled until it snaps off, and the remaining projecting part is trimmed flush with the head.
Name at least three types of self plugging mechanical lock rivets:
Cherry Max
Cherry lock
Olympic lock
Huck lock
What is the difference between the tools required to pull a cherry lock rivet and a cherry Max rivet?
Cherry Lock - requires a tool for each different size and head shape.
Cherry Max - one pulling tool will set any size.
Which of the five stresses is the most common cause of a rivet failure?
Shear.
If a 2024 rivet must be replaced with a 2117 rivet, how do you determine the size to be used?
For 5/32 inch or smaller diameter, use the next larger size 2117 rivet, assuming that the edge distance and spacing meet the minimum requirements. 
Describe the process for determining the total length of a solid rivet for a particular installation.
Add the grip length (thickness of the materials being joined) plus 1.5 times the river diameter.
What minimum edge distance and spacing should be used for a single row of protruding head rivets?
Not less than two rivet diameters from the edge, and not less than three rivet diameters apart.
How can a mechanic determine whether the countersync for a flush rivet should be dimpled or drilled?
By the thickness of the top sheet; thin sheets are dimpled, while 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 set that does not properly fit the rivet?
If the radius of the seat is too small, the rivet head may be damaged.
A set with an oversized radius may cause damage to the sheet metal.
Why is it important to use the proper size and weight bucking bar when performing sheet metal riveting?
If a bucking bar is too large, it may be difficult to control and cause damage to the surrounding structure.
A bucking bar that is two 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.
Drill to the base of the rivet head with the same size or one size smaller drill.
Use a punch to tip off the rivet head.
Drive the remaining shank out of the hole while supporting the surrounding metal. 
What are the two special calculations that must be made when bending sheet metal?
Bend allowance.
Setback.
What factors must be considered in order to determine setback?
Thickness of the metal.
Bend radius.
What is done to a corner where two bends intersect to prevent cracking?
Relief holes are drilled in the corner.
What are the two reasons for installing a lightening hole in a sheet metal wing rib?
Lightening holes reduce the weight and increase stiffness.
Describe a joggle and explain its function.
A joggle is an offset formed at an intersection of two or more sheets of metal to allow the multiple sheets to be stacked flat against each other.
When repairing an all metal aircraft, how do you determine what metals should be used?
Always use metal of the same type and thickness as the original structure.
