AMCR MIDTERMS Flashcards
The most common technique of joining sheets of
aluminum is this. A _____ is a metal pin with a formed head on one end. A
_____ is inserted into a drilled hole, and its shank is then deformed by a hand or
pneumatic tool. ____ create a union at least as strong as the material being
joined.
Rivets
It has been used since sheet metal was first utilized in
aircraft and remains the single most used aircraft fastener today.
Solid Shank Rivet
When a rivet is driven, its cross-sectional area _____ along with its
bearing and shearing strengths.
increases
Rivet Codes that are used today
Air Force - Navy, or AN system,
and the Military Standards 20 system, or MS20.
The two most common rivet head styles
Universal head and Countersunk
What is the code of the universal head
470
What is the code of countersunk
426
These were developed to streamline airfoils and permit a
smooth flow over an aircraft’s wings or control surfaces.
AN426 (countersunk rivets)
before a
countersunk rivet can be installed, the metal must be ________
countersunk or dimpled
It is a process in which the metal in the top sheet is cut away in the
shape of the rivet head.
Countersinking
It is a process that
mechanically “dents” the sheets being joined to accommodate the rivet head.
Dimpling
Rivet Code of a universal head
AN470 - MS20470
Rivet Code of a flat head
AN442
Rivet Code of a roundhead
AN430
Rivet Code of a Brazier Head
AN455
To provide a smooth finish after
the rivet is driven, the protruding rivet head is removed using a ____ . This
rotary cutter shaves the rivet head flush with the skin, leaving an aerodynamically
clean surface.
Microshaver
An alternative to leaving the rivet head sticking up slightly is to use the _________.
Alcoa crown flush rivet
the amount of force that is
needed to cut a rivet into two
Shear Strength
the amount of force that will
cause the rivet to tear out from the metal
Bearing Strength
Rivets made of pure aluminum have no identifying marks on their manufactured head
and are designated by the letter A in the rivet code.
1100 Aluminum (Rivet Code: A)
is the most widely used for manufacturing and maintenance of
modern aircraft. Rivets made of this alloy have a dimple in the center of the head and
are represented by the letters AD in rivet part codes. Because AD rivets are so common
and require no heat treatment, they are often referred to as “field rivets.”
2117 Aluminum Alloy (AD) or 2117-T3
Some aircraft parts are made of magnesium. If aluminum rivets were used on these
parts, dissimilar metal corrosion could result. For this reason, magnesium structures
are riveted with 5056 rivets which contain about 5 percent magnesium. These rivets
are identified by a raised cross on their heads and the letter B in a rivet code.
5056 Aluminum Alloy (B)
the aluminum industry modified 2017 alloy to produce a new version of 2017 aluminum,
called the _________.
crack free rivet alloy
are identified by a raised dot in the center of their head and the letter D in rivet
codes. Because D-rivets are so hard they must be heat treated before they can be used.
2017 Aluminum Alloy (D)
are identified by two raised dashes on their head.
DD-Rivets / 2024 Aluminum Alloy (DD)
This alloy contains zinc as the major alloying ingredient and is precipitation heat-treated.
This alloy is used by the Boeing Airplane Company as a replacement for 2024T31 rivets
in the manufacture of the 767 widebody aircraft.
7050-T73 Aluminum Alloy (E)
Stainless steel rivets are used for fastening corrosion-resistant steel sheets in
applications such as firewalls and exhaust shrouds. They have no marking on their
heads.
Corrosion Resistant Steel (F)
This rivets are identified with two recessed dimples in their heads. They are used in
place of corrosion-resistant steel rivets when their somewhat lower shear strength is
not a detriment.
Monel (M)
used for fastening
steel and titanium alloy.
Titanium (T)
AMS
Aeronautical Material Specifications
AN
Air Force-Navy
AND
Air Force-Navy Design
AS
Aeronautical Standard
ASA
American Standards Association
ASTM
American Society for Testing and Materials
MS
Military Standard
NAF
Naval Aircraft Factory
NAS
National Aerospace Standard
SAE
Society of Automotive Engineers
These rivets are installed with
access to only one end of the rivet.
Special Rivets or Blind Rivets
These rivets have limited use on aircraft and are never used for structural repairs. Useful for temporarily lining
up holes; used in some homebuilt aircraft
Pop Rivets
develop the maximum strength from the sheet metal
as determined by the amount of load that the sheet
metal must carry.
Rivet Layout Pattern
metal sheet will tear out in extreme conditions
If it’s too close to the edge
metal sheet separates; contaminants enter the join
causing corrosion for instance.
If it’s too far from the edge
no closer than _____ rivet shank diameters from
the edge and no further back than _____ diameters
2, 4
the distance between adjacent rivets in a row.
Rivet Pitch
Accepted Practice in Rivet Pitch
3D-12D
the distance between rows of rivets in a
multi-row layout.
Transverse Pitch
Accepted practice in Transverse Pitch
75% RP, if staggered
RP=TP, if not staggered
safer to use; less chances of electric
shock and arcing; motor speed is controlled by varying
trigger pressure.
Pneumatic Drills
what type of dimpling that uses a forging action
Coin Dimpling
what type of dimpling that uses a folding action
Radius Dimpling
Two types of Dimpling
Double-Dimple, Dimple-Countersunk
When installing rivets, it is important to install the
rivet with as _________ as possible so the materials
will not work-harden and crack.
few impacts
3 Types of Rivet Installation
Hand Riveting, Compression Riveting, Gun Riveting
radius of depression in the set
must be larger than that of the rivet head, but
not so large that the edges of the set contract
the surface of the metal.
Rivet Set
When a rivet is driven,
the actual compression of the rivet is
not performed by the action of the
rivet gun, instead, the rivet is backed
up by a metal bar that reciprocates in
response to the beats of the rivet gun.
Bucking Bar
early form of
blind rivet. It cannot replace solid
shank rivets size for size and must be
at least one size larger in diameter.
Center stem is one of its drawback
Cherry friction-lock rivet
designed to prevent the
center stem of a rivet from falling out via lock ring as a
result of vibration encountered during aircraft operation
Mechanical Lock Rivets
first mechanical lock rivet; limited to
aircraft manufacturers and large repair facility
Huck-Lock
requires a special pulling tool
per size and head shape.
bulbed CherryLOCK
lightweight, spindle-type blind rivet;
less expensive, only 3 installation tools are required
Olympic-Lok
economical and replaces solid shank
rivets size for size; installed by a one size puller for
all sizes.
CherryMAX
4 types of mechlocktype rivets
Huck-Lock, Bulbed CherryLOCK, OlympicLOK, CherryMAX
high strength and light weight fastener that can be used
in place of conventional AN bolts and nuts. Held in place
by a collar, squeezed into position instead of being
screwed on like a nut.
Special Fasteners
for both shear and tension applications
Lock Bolts
withstand bearing and shearing loads
Hi-Lok Bolts
excellent strength to weight ratio;
lighter
Hi Lite Fastener
one piece fastener made of 2 titanium
alloys
CherryBuck
strongest; creates radial and vertical
compression
TaperLok
has a bead at the threaded end;
preloads the hole to strengthen the joint
Hi Tigue Fastener
threaded rivets; attach rubber
deicer boots to aircraft wing and tail surfaces
Rivnuts
secure inspection
plates, doors cowlings and other removable
panels on aircraft.
Ex. Dzus Fastener
Turn-lock Fasteners
unlike rivets and pins, these may be
disassembled and reassembled an almost infinite
number of times.
Threaded Fasteners
4 classifications of threads
American National Coarse (NC)
American National Fine (NF)
American Standard Unified Coarse (UNC)
American Standard Unified Fine (UNF)
designated by the number of times the incline
(threads) rotates around a _____ inch length of given
diameter bolt or screw. (Thread Designation)
1
Class 1
loose fit – fingers only – wing nuts
Class 2
free fit - screws
Class 3
medium fit – aircraft bolts
Class 4
close fit – requires wrench
Class 5
tight fit - requires wrench
The hole is larger than the shaft, enabling the
two parts to slide and / or rotate when assembled.
Clearance Fit
The hole is fractionally smaller than the shaft
and mild force is required to assemble / disassemble
Transition Fit
The hole is smaller than the shaft and high
force and / or heat is required to assemble / disassemble
Interference Fit
Fastener Diameter
1/16 inch increment
Fastener Length
1/8 inch increment (1/8 – 7/8 only)
Letter “H” after the number indicating the diameter
drilled head
Letter “A” after the dash number
undrilled shank
Why head is drilled
for safetying
AN73 to AN81
similar to the standard hex bolt, but has a deeper
head that is drilled to receive wire for safetying.
Letter “A” before the dash number – coarse threaded
Drilled Head Bolt
AN173 to AN186 – Hex head
NAS80 to NAS86 – Countersunk head
Identified by a cross or asterisk inside a triangle
used in areas that are subject to pounding loads
or in a structure that is required to be both riveted
and bolted.
Close Tolerance Bolt
AN21 to AN36
Domed head that is either
slotted or recessed; mostly
safetied with a cotter pin
Shorter threaded shank, thus
longer grip length
Both diameter and length are
measured in 1/16 in increment
applications requiring shear
loads only; control cables
Clevis Bolts
A sort of locking device is a must to prevent nuts from
loosening and falling off.
Aircraft Nuts
two basic types of nuts
self locking nuts, non self locking nuts
locks onto a bolt on its own
self locking nuts
relies on either a cotter pin, check
nut, or lock washer to hold it in place.
non self locking nuts
Code of Castle Nut
AN310
Code of Shear Castle Nut
AN320
Code of Plain Nut
AN315
2 types of self locking nuts
Fiber or Nylon Type / All metal type
3 types of other aircraft nuts
Wing Nut, Anchor Nut, Tinnerman Nut
made of lower strength materials compared to bolts
loose-fitting thread; class 2 fit
head shapes are made to engage a screwdriver or wrench
Aircraft Screws
3 Basic Classification of aircraft screws
Machine Screw, Self tapping screw, Structural Screw
used in shear applications and for safetying
Aircraft Pins
4 types of aircraft pins
Roll, Clevis, Cotter, Taper
provide a bearing surface area for nuts
act as spacers
shims to obtain the proper grip length
for a bolt and nut assembly
Aircraft Washers
strong and light weight, and its flexibility makes it easy to route.
actuate flight controls, engine controls, emergency landing gear
extension controls and trim tab systems.
Aircraft Control Cables
develop 75% of
the cable strength
Ex. Army-Navy 5 tuck splice /
Roebling roll
Woven Splices
used most in
large aircraft manufacture. At
least as strong as the cable
Swaged Terminals
squeezed onto control cables
to form terminal ends, and place AN100 thimble
inside the loop. At least the same strength of the
cable.
Nicopress Sleeves
allows cable tension to be adjusted.by
rotating it.
Turnbuckle
prevents cable contact to other parts of
the aircraft
Fairlead
changes direction of travel
Pulley
changes motion through an angle;
Ex. rudder mechanism
Bellcrank
