Sheet Metal Construction, Tools, and Fabrication (Jeppesen Sections A, B, and C Before bending)

What are the 5 types of stresses? What are the 2 primary stresses?

1. Tension (Primary)

2. Compression (Primary

3. Bending

4. Torsion

5. Shear

How must a joint be manufactured to deal with extreme loads?

The joint must be manufactured in a way such that the fasteners will fail before the base metal does.

What are the 3 duties of a proper aircraft structure repair?

• Accept all of the loads

• support the loads

• transfer any loads back into the structure

List the aluminum alloying agent for each of the following:

1xxx

1xxx - Aluminium

List the aluminum alloying agent for each of the following:

2xxx

2xxx - Copper

List the aluminum alloying agent for each of the following:

3xxx

3xxx - Manganese

List the aluminum alloying agent for each of the following:

4xxx

4xxx - Silicon

List the aluminum alloying agent for each of the following:

5xxx

5xxx - Magnesium

List the aluminum alloying agent for each of the following:

6xxx

6xxx - Magnesium and Silicon

List the aluminum alloying agent for each of the following:

7xxx

7xxx - Zinc

List the aluminum alloying agent for each of the following:

8xxx

8xxx - Other Elements

What is the purpose of an alclad coating?

Greatly improve corrosion resistance, so long as there are no scratches or abrasions

What are the 2 types of heat treatments?

Solution Heat Treatment

Precipitation Heat Treatment

What is the purpose/outcome of Annealing?

Annealing softens a metal and decreases internal stresses

opposite of hardening.

What are the 3 most common heat treating designations?

1. -T3

2. -T4

3. -T6

What diameter rivet is used with a No. 40 Drill bit?

3/32 or 3- Rivet

What diameter rivet is used with a No. 30 Drill bit?

4/32 or 4- Rivet

What diameter rivet is used with a No. 21 Drill bit?

5/32 or 5- Rivet

What is the difference between a cornice (or leaf) brake and a box brake?

A box brake is similar to a cornice brake, except that it has split leaves to allow bending of different sections of metal without bending other sections.

What is a slip roll former used for?

to make gentle curves in a large piece of sheet metal, typically for skin replacements on a fuselage.

Why would a shrinker or stretcher be used?

Shrinkers can be used to more easily form inside curves

Stretchers can be used to form outside curves

both of these tools can be used to prevent tearing of the metal, especially thick metal, when tight curves are being formed.

What are the three most common fasteners that can be used to temporarily hold/align sheet metal structures during fabrication?

1. Cleco Fasteners

2. C-Clamps

3. Wingnut clamps

List the color that corresponds with each hole size below:

• 3/32”

• 1/8”

• 5/32”

• 3/32” - Silver

  1/8” - Copper

  5/32” - Black

What is the purpose of a hole finder?

a hole finder helps transfer old holes on old skin sheets to new sheets

What is the purpose of a chip chaser?

to remove metal chips between skins that cannot be disassembled after drilling

what does the rivet code “470” indicate?

a rivet with a universal head

what does the rivet code “426“ indicate?

A rivet with a countersunk head

What does each part of “MS20426DD5-6” mean?

MS20426 : Head style

DD : Material

5 : Diameter (1/32 inch increments)

4 : Length (1/16 inch increments)

How are the lengths of universal and countersunk rivets measured?

Universal: measured from the bottom of the manufactured head to the end of the shank

Countersunk: Measured from the top to bottom, including the manufactured head

What are the two must common rivet materials? how are their heads indicated?

AD rivets: Indicated by a small dimple on their head, AKA field rivets

DD Rivets: AKA “Icebox rivets”, indicated by two raised dashes on their head.

What are Rivnuts used for?

attaching parts and pieces with screws to sheet metal, commonly found in GA cowlings and access pannels

What are the 3 types of turnlock fasteners used today? what are they used for

Dzus

Airloc

Camloc

Commonly used for quick access panels for inspection and/or servicing purposes

when driving a rivet, what should the dimensions of the shop head be?

width: 1.5 D

Height: ½ D

When selecting the length of a rivet, what is a good rule of thumb to use?

The rivet should be

1.5 D + the grip length of the material

in length

What is the standard edge distance for rivet layout patterns?

2 ½ times the rivet diameter

What is the pitch of a rivet layout?

the distance between adjacent rivets in a row.

commonly, rivet pitch should be between 3D-12D

What is the gauge of a rivet layout?

The distance between rows of rivets in a multi-row layout.

what are the acceptable measurements of the gauge for staggered and non staggered layouts?

Staggered: Rivet gauge should be about 75% of the pitch

Non Staggered: Rivet gauge should equal pitch

what is the difference between a clearance fit and an interference fit?

Clearance fit: The fastener is smaller than the hole, allowing the fastener to easy slip into the hole

Interference fit: The fastener is larger than the hole, requiring the fastener to be driven into place

What is required after a hole is drilled, but before the rivet is installed?

Deburring, to remove any excess material from around the edges of the sheet metal hole

what are the 4 methods of rivet installation

1. Hand Riveting

2. Compression Riveting

3. Gun Riveting

what is a rivet set? what is the ideal size for a cupped rivet set?

A rivet set is the tip of the rivet gun, which have different sizes based on the different size universal head rivets.

the idea size for the cup of the rivet set is slightly larger than the radius of the rivet head

Explain the process of removing a rivet

1. using a drill slightly smaller than the size of the rivet head, drill down to the base of the rivet head

2. use a pin punch to pry the head off

3. back up the underside of the skin with a bucking bar

4. use a pin punch to drive the rivet shank out

what is NACA Flush riveting?

A process where universal head rivets are installed from the inside out, then their shop heads milled flush. this process is more flush than even countersunk rivets.