SHEET METAL AND NON-METALLIC STRUCTURES

Question 1

How do you determine the total length of a solid rivet for installation?

Answer 1

The grip length +1.5 x the rivet diameter.

Question 2

What is done with the rivet head stem when a self plugging rivet is installed?

Answer 2

The stem is pulled until it snaps off and the remaning projecting part is trimmed flush with the head.

Question 3

Give examples self plugging mechanical lock rivets.

Answer 3

CherryLOCK, CherryMAX, CherrySST, HulkLOCK and OLYMPIC-LOCK.

Question 4

What methods are used in forming sheet metal?

Answer 4

Shrinking, Stretching, Bumping, Crimping, Folding.

Question 5

What factors are used to determine setback?

Answer 5

Bend radius and material thickness

Question 6

What calculation must be made when bending sheet metal?

Answer 6

Bend Allowance and setback.

Question 7

What must be done when two bends intersect to prevent cracking?

Answer 7

Relief holes are drilled at the intersection/corner.

Question 8

What is a joggle?

Answer 8

Its the offset formed on a part to allow clerance for a sheet or another mating part.

Question 9

What is the purpose of lightning holes cut in rib sections?

Answer 9

To reduce weight and increase off stiffness.

Question 10

Describe rivet head markings for A,B,D,AD and DD rivets:

Answer 10

A – Are Plain, B – Have a Cross, D – Have a Raised Dot, AD – Have a Dimple, DD – Have a double dash.

Question 11

What are the correct dimensions on a properly formed rivet head.(shop head)

Answer 11

1 ½ the shank diameter and ½ the shank of diameter hight.

Question 12

How do you determine the proper material to be used for a repair of an all metal aircraft?

Answer 12

Use the same type and thickness of the material that was used in the original structure.

Question 13

What is the single row spacing and edge distance for protruding head rivets?

Answer 13

Edge 2 x diameter; Spacing 3 x diameter.

Question 14

Describe the criteria for replacement of a 2024 rivet with a 2117 rivet for general repairs.

Answer 14

For 5/32 or less diameter, use the next larger size rivet 2117 and the edge/spacing distance meet the minimum
requirements.

Question 15

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

Answer 15

Corrosion.

Question 16

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

Answer 16

CherryLOCK – Require a different tool for each rivet size.
CherryMAX – Same tool for all.

Question 17

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

Answer 17

By the thickness of the top sheet, thin sheets are dimpled and thick sheets may be countersunk.

Question 18

What action is taken to prevent cracks from forming while dimpling magnesium or some hard sheet
metals?

Answer 18

Hot dimpling equipment is used to preheat and soften the metal before the dimple is formed

Question 19

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

Answer 19

The rivet head and the sheet metal may be damaged.

Question 20

Why is it important to use the proper bucking bar when performing sheet metal riveting?

Answer 20

Bucking bar too large or heavy – Difficult to control and you can damage the sheet metal.
Bucking bar too light – Will not properly upset the rivet before work hardening occur.

Question 21

What procedures should be followed to properly remove a solid-shank rivet?

Answer 21

Center punch the rivet and drill to the base of the rivet head using the same size oro ne size small drill, then use a pin
punch to tip off the rivet head.

Question 22

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

Answer 22

Shear.