Sheetmetal & Non-Metallic Structures Flashcards
Example of a self-plugging rivet;
Cherry lock, cherrymax or Huck
What is done with the stem of a friction lock rivet?
Trimmed flush with head.
What tool is used to install Cherrylock rivets?
Hand or air puller.
A proper rivet shop head is;
Width = 1 1/2 diameter of rivet shank Height = 1/2 diameter of rivet shank
What is bonded honeycomb construction?
Laminar (two metal sides bonded to honeycomb).
What materials are used in bonded honeycomb?
Stainless, titanium, magnesium, plywood, glass, nylon and cotton cloth, aluminum, Kevlar, carbon, steel, paper
What causes the delaminating of honeycomb?
Sonic vibrations, moisture, entrapped water, manual flaw.
What is potting compound used for?
Fill holes in honeycomb (1” max)
What kind of repair can be made to a small damage of the core material and one face sheet of a piece of aluminum alloy honeycomb structure?
A potted compound repair.
What is done with the damaged area of honeycomb?
Must be removed.
What is (and what causes) crazing?
Tiny hair-like cracks that may not extend all of the way to the surface. Crazing is caused by stresses, improper handling, or chemical fumes (Ex; harmful solvents).
How do you drill plexiglas?
Brace with wood, and feed drill slowly.
How do you grind the point of a twist drill that is to be used for drilling transparent acrylic material?
The cutting edge should be dubbed off to a zero rake angle, and the included angle of the tip should be ground to 140 degrees.
Calculations made when bending sheet metal include;
Bend allowance and setback.
What must be done where two bends intersect?
Relief holes drilled.
What type of weathering damage may be found on aluminum aircraft?
Corrosion.
Methods of forming sheetmetal include;
Shrinking, stretching, bumping, crimping, and folding.
What is (and what factors affect) setback?
The distance the jaws of a brake must be set back from the mold line to form a bend. Factors of setback are bend radius and material thickness.
The purpose of lightening holes is to?
Reduce weight.
What is meant by a joggle in a piece of sheetmetal?
A joggle is a small offset near the edge of a piece of sheet metal that allows the sheet to overlap another piece of metal.
How long should a rivet be to join two pieces of sheet metal?
Combined thickness of the metal sheets plus 1-1/2 times the rivet shank diameter.
The proper material for a given repair is;
***
Same as the original.
***
Single row spacing and edge distance of protruding head rivets is?
Edge distance = 2D
Spacing = 3D
Describe rivet head markings; 1100 - 2017 - 2117 - 2024 - 5056 - 7075 -
1100 - Plain 2017 - Raised dot 2117 - Recessed dot 2024 - Raised double dash 5056 - Raised cross 7075 - Three raised dashes
Types of Alloys are?
1xx - 4xx - 7xx -
2xx - 5xx - 8xx -
3xx - 6xx - 9xx -
1xx - Aluminum 2xx - Copper 3xx - Manganese 4xx - Silicon 5xx - Magnesium 6xx - Magnesium & Silicon 7xx - Zinc 8xx - Other 9xx - unused series
What determines whether a piece of sheet metal should be dimpled or countersunk when installing flush rivets?
The thickness of the sheet. Countersinking should only be done when the thickness of the sheet is greater than the thickness of the rivet head.
Most common rivet failure is?
Shear loading.
Should a riveted joint fail in shear or in bearing?
It should fail in shear. The rivets should shear before the sheet tears at the rivet holes.
Replacing a 2024 w/ 2117?
For 5/32 or use next larger size of 2117.
Bolts w/ triangle on head;
Bolts w/ dash on head;
Triangle = close tolerance bolt Dash = Corrosion resistant bolt
