Sheet Metal

Question 1

Name several methods for forming sheet metal

Answer 1

Bending or folding, stretching, shrinking, bumping, and crimping

Question 2

What are the dimensions of a properly formed rivet head

Answer 2

Head should be 1 1/2 times the shank diameter and 1/2 the shank diameter in width

Question 3

Describe the markings found on the heads of A, B, D, AD,and DD rivets

Answer 3

• A plain – 1100 – Pure aluminum
  • B cross – 5056 - Magnesium
  • AD raised dot – 2117 – Universal
• D dimple – 2017 – “Ice box”
  • DD double dash – 2024 – “Ice box”

Question 4

What happens to the stem of a self- plugging rivet when the rivet is installed

Answer 4

The stem is pulled until it snaps off and the remaining part is trimmed flush with the head

Question 5

Name at least three types of self plugging mechanical lock rivets

Answer 5

CherryMax , CherryLOCK, and OLYMPIC LOK

Question 6

What is the difference between the tools required to pull a CherryLOCK rivet and a CherryMax rivet

Answer 6

CherryLOCK rivets require a tool for each different size and head shape while one pulling tool will set any size CherryMAX rivet

Question 7

Which of the five stresses is the most common cause of rivet failure

Answer 7

Shear

Question 8

Describe the process for determining the total length of a solid rivet for a particular installation

Answer 8

Add grip length plus 1 1/2 times the rivet diameter

Question 9

What minimum edge distance and spacing should be used for a single row of protruding head rivets

Answer 9

No less than two rivet diameter from the edge and no less than three rivet diameter apart

Question 10

What type of damage can occur when using a rivet set that does not properly fit the rivet

Answer 10

If to small rivet head may be damaged if to big sheet metal will be damaged

Question 11

What procedure should be followed to properly remove a solid shank rivet

Answer 11

Center punch the rivet
Drill just to the base of the rivet head with same size or one size bigger drill bit
pin punch to tip off the rivet head
Then drive the remaining shank out of the hole

Question 12

What are the two special calculations that must be made when bending sheet metal

Answer 12

Setback and bend allowance

Question 13

What factor must be considered in order to determine setback

Answer 13

The thickness of the metal and the bend radius

Question 14

What is done to a corner where two bends intersect to prevent cracking

Answer 14

Relief holes are drilled

Question 15

What are the toe reasons for installing a lightning hole in a sheet metal wing rib

Answer 15

Reduce weight and increase stiffness

Question 16

Describe a jiggle and explain its function

Answer 16

Small offset near the edge of a piece of sheet metal . Allows one sheet of metal to overlap another while maintaining a flush surface

Question 17

When repairing an all metal aircraft how do you determine what metals should be used

Answer 17

Always use same type and thickness as the original structure

Question 18

What is the major type of damage to aluminum structures that is caused by exposure to the weather

Answer 18

Corrosion

Question 19

What causes honeycomb structure to delaminate

Answer 19

Moisture

Question 20

What is used for hole filling in bonded honeycomb repair

Answer 20

Potting compound

Question 21

What size drill should be used for common shank rivet diameters of 3/32inch ,4/32 / 1/8 inch , and 5/32 inch

Answer 21

3/32 rivet # 40. For a 4/32 or 1/8 rivet #30. For a 5/32 rivet # 21

Question 22

What type of rivet may be used to replace a round head rivet in an aircraft

Answer 22

Universal head rivet

Question 23

What are two types of resins used in aircraft construction

Answer 23

Thermoplastic and thermosetting

Question 24

What are two parts of an epoxy matrix material

Answer 24

Resin and hardener

Question 25

What is necessary to cure a thermosetting resin

Answer 25

Heat

Question 26

The rivet to use for joining two sheets of metal should have a diameter of what

Answer 26

3 times the thickness of the thickest sheet being joined

Question 26

What is the distance between the center of the rivet holes in a single row of rivets is called

Answer 26

Rivet pitch

Question 27

How can a mechanic determine whether the countersink for a flush rivet should be dimpled or drilled

Answer 27

The thickness of the top sheet thin sheets are dimpled well thick sheets are countersunk

Question 28

The shank of a rivet should stick out the the sheet by

Answer 28

1 1/2 times shank diameter