6.5 fasteners Flashcards
(295 cards)
1
Q
What can be used to measure the screw thread pitch?
A
A screw thread pitch gauge
2
Q
How do you know if the thread pitch has been identified?
A
If the gauge matches up with the thread
3
Q
What are screw thread pitch gauges used for?
A
To identify external or internal screw threads
4
Q
What does the class of fit indicate?
A
The tolerance
5
Q
What does Class 1-5 mean?
A
Class 1 loose fit
Class 2 free fit
Class 3 medium
Class 4 close
Class 5 tight
6
Q
What class are aircraft bolts normally?
A
Class 3
7
Q
What does a class 4 fit require that a class 1 fit doesn’t?
A
A wrench, whereas a class 1 can turned with fingers
8
Q
What class are aircraft screws manufactured in?
A
Class 2 thread fit
9
Q
What is BSW summed up?
A
British standard course thread which is recommended for general purpose works in metal and plastic
10
Q
What about the BSW thread makes it suitable for quick assembling and disassembling of components?
A
The Whitworth thread
11
Q
What are the features of a BSW?
A
It has a symmetrical vee shape and an angle of 55 degrees and is roused weekly at the root and the crest
12
Q
What is BSF summed up?
A
It is a finer version of the Whiteworth thread form
13
Q
What two important features related to a finger thread do BSF have?
A
It increases the resistance against vibration and creates a finer form of adjustment
14
Q
A BSF screw will always have more screws per what?
A
2.5cm
15
Q
What is BSP summed up?
A
Another finer thread adaptation of the Whitworth thread form
16
Q
Where are a BSP used?
A
In pipe couplings
17
Q
What can ensure a BSP has a pressure tight joint?
A
What can ensure a BSP has a pressure tight joint?
18
Q
What does the fine pitch ensure on BSP?
A
Uncut metals remain on the wall of a pipe
19
Q
What is BA summed up?
A
A fine pitch thread used for 6.35 (1/4) in diameter only
20
Q
What is BA used for?
A
Smaller mechanical and electrical parts
21
Q
What is different about expressions in BA?
A
They’re expressed numerically
22
Q
in BA threads, what is the popular size range?
A
0-10
23
Q
In BA threads, the larger the number….
and the smaller the number….
A
The smaller the thread
The larger the thread
24
Q
Why does the BA differ in terms of degrees?
What is retained?
A
47.5 degrees
The feature of equal rounding for root and crest
25
What are the American standard threads?
ANF
ANC
26
What are the features of AN thread forms?
The flattening of the crest and root in the AN is not equal and the thread angle sits at 60 degrees.
27
What are unified thread forms?
Incorporates features from British and American national threads
28
Are the differences in the American and British interchangeable?
Yes
29
What are the three versions of UN?
UNC
UNF
UNEF
30
What does the shape or profile of the screw thread depend upon?
Its job
31
What is the symmetrical vee thread designed to combine?
Strength with ease of engagement
32
What do square roots have powerful of?
Roots
33
34
35
What are square threads used for?
Carrying heavy loads, transfer of power and exerting, screw jack and vice spindle
35
The specific measurement or number per inch of threads are not what in square roots?
Particular
36
What are buttress threads?
They have a triangular section, one face at the right angle and the other is sloped
37
What power do buttress threads have?
Pulling
38
What are ACME threads summed up?
Similar to square threads but are tapered
39
What are ACME threads summed up?
Similar to square threads but are tapered
40
Because of ACME's slanted ends, what is made easier?
easier to fix or unscrew the split nut but do not have backlash in it
41
What is ACME's degrees?
29 degrees
42
What are squares ideal for?
Ideal thread for power transmissions
43
Is acme stronger than square threads?
Yes
44
What are the buttress threads designed for?
Designed to handle forces in one direction
(eg true jack)
45
What does a nut act as?
Secure it in place
46
What is a boot used for?
To hold two or more items together
47
What is a bolts diameter increments in?
What is a bolts length increments in?
1/16
1/8
48
What type of heads do bolts have?
Hex
49
What does the diameter of a bolt equalate to?
The Diameter of the shank
50
What is a bolts grip length?
The length of the unthreaded portion
51
When must washers be added to a bolt and why?
If the grip length is slightly longer than the total thickness of the material
52
What can result in a weaker joint?
When the thread goes into the material because the grip length is less than the thickness of the material (thread goes in)
53
What does 'A' mean in a bolt?
It is not drilled for a split pin
54
What is the diameter in, AN3-6A
What is the length?
What does 'A' mean
3 diameter in 1/16
6 length in 1/8
It does not have a hole for a split pin
55
How do you know if it is drilled for a split pin?
There is no letter
56
How is a corrosion resistant bolt identified?
With the letter C (in between length and diameter)
57
How are aluminium alloys identified?
DD
58
How does a cadmium plated nickel steel look?
A star
59
How does corrosion resistant bolt look?
A single dash
60
How does 2024 aluminium bolt look?
Two dashes
61
What do bolts have marked on their heads?
Material identification NDT manufacturer's data
62
What size does the FAA forbid?
AN3
63
What are not allowed to be used in sea planes?
Aluminium alloy nuts used with cadmium plated steel bolts in shear
64
What AN bolts must be wire locked?
Fastening propellers
65
A wire locking bolt has what letter?
H
66
When are clevis bolts used?
in shear
67
What AN is clevis bolts?
AN21 AN36
68
What does a clevis bolt look like?
It has a domed head that is slotted
69
what is a unique feature of a clevis bolt?
Only a small portion of the shank is threaded
70
What does the small notch between the threads and shank do?
Long grip length which increases the bolts shears strength and allows the bolt to move more freely
71
What is the length and diameter of a clevis pin?
1/16
72
What AN are eye bolts?
AN42 AN49
73
AN42 AN49
Where external tension loads are to applied
74
What is the head of an eyebolt specifically designed for?
Attachment of turnbuckle which connects two cables
75
What is the threaded shank drilled for?
Safe tying
76
What AN are drilled head engine bolts?
AN73 AN81
77
What is different about drilled engine heads?
They are thicker and have drilled heads in the centre of the head and around the flats
78
What is the diameter of a drilled engine head?
What is the length?
1/16 increments
1/8 increments
79
What AN are close tolerance bolts?
AN 173 AN186
80
What is the close tolerance bolts tolerance?
+0.000 -0.0005 inch
81
Where are close tolerance bolts used?
In areas prone to pounding or in a structure that is about to be rivited or bolted
82
How can you recognise a close tolerance bolt?
It has a triangle on its head
83
When are internal wrenching bolts used?
When are internal wrenching bolts used?
84
What sided hole is drilled into internal wrenching bolts?
6 sides to accept an Allen wrench
85
What must occur to the hole when installed in steel parts to accommodate the radius?
Counterbore
86
When an internal wrenching bolt is installed in aluminium structure, why must a washer be used?
To pre de needed bearing area.
87
What must an AN bolt never be substituted for?
An internal wrenching bolt
88
What are the NAS length increments?
1/8
89
Where is the grip length measured on a NAS bolt?
Beneath the head end of the thread
90
What are odd dash numbers?
Special application bolts
91
What are odd dash number's grip length longer than?
1/16
92
When are odd dash numbers used?
Where a standard MS bolt is either too long or too short
93
What does the basic NAS number identify?
The part
94
What are most aircraft's bolts measured by?
Their grip length
95
How do AN bolts bolts differ in terms of measuring?
They're measured by their overall length
96
What are MS bolts' dash numbers like?
Even
97
Where are odd dash numbers available in MS bolts?
When the grip length is critical and a standard grip is either too long or too short
98
Where must the load be on an MS bolt?
On the shank not on the thread
99
What must you refer to when purchasing fasteners?
Aircraft illustrated parts
100
how many numbers are NSA specification?
Is a four digit number
101
What is the first dash in the four digit specification in NSA?
What is the second dash number?
The diameter in 1/16 increments
1/16 in grip length
102
Where are studs installed?
In internal threads in a casting or built up assembly
103
If internal threads are damaged, what are the two alternatives?
To repair the part or repair and replace the threads
104
What does Heli Coil protect against?
Wearing because of continuous insertion
105
Heli coils are available for what type of thread standards?
All
106
What sort of cross section does helicoils have?
Diamond cross section
107
When will the tang break off?
When it reaches a certain tension
108
What are the two types of Heli coil?
The standard types
The screw lock type
109
What is a standard type of Heli coil?
Provides a free running thread
110
How do Heli coil inserts compensate for their lead and angle errors?
They self adjust
110
What is a screw lock type Heli coil?
Provides a resilient internal lock thread
111
How do screw's differ from bolts?
They are made from a lower strength materials
112
What threads are screws fitted with?
A loose fitting thread
113
What are the head shapes of screws made for?
To engage a screwdriver or wrench
114
What are the three basic classifications of screws?
Machine screws
Structural screws
Self tapping screws
115
What do structural screws have the same strength as?
Bolts
116
What are self tapping screws used for?
To join lightweight materials
117
What are machiene screws used for?
Attaching light structural parts such as fairings or fluid lines
118
What is the main difference between aircraft's screws and bolts?
Threads of machine screws run the full length of the shank
Bolts have a unthreaded grip length
119
What class fit do machine screws have?
Class 2 (loose fit)
120
What are the most common machiene screws used in aviation?
Fillister screws, the round head screws, the flat head screw the truss head screw
121
What are structural screws made out of?
Alloy steel that are heat treated
122
What else can stuctural screws be used for?
Structural bolts
123
What are structural screws available with?
Fillister flat or washer heads
124
What are the threads used in structural screws?
National fine, hex head bolts
125
What must you never use on a torque set screw?
A Philips screwdriver
126
What must you never use on a Hi torque screw?
A slotted screwdriver
127
What threads do self tapping screws have?
Course threads
128
What are self tapping screws used for?
To hold thin sheets of metal plastic or plywood
129
What does type A self tapping screws have?
A gimlet (sharp point)
130
What does type B self tapping screws have?
A blunt point with thinner threads
131
What are the four types of heads available on self tapping screws?
Round head
Truss head
Countersunk
Countersunk oval
132
What is different between the round head screw and the truss head screw?
The truss head screw is thinner
133
What is a dowel?
A solid cylindrical rod
134
What is a dowel called in its original manufactured form?
A dowel rod
135
When are dowels used?
Where precision alignment and correct orientation of two mating surfaces is required.
136
Smooth solid dowel pins are made with high quality steel metallic to ensure what?
Smooth solid dowel pins are made with high quality steel metallic to ensure what?
137
What are split hollow dowels used for?
To maintain alignment and act as bushing for rotating
138
What do structural screws have the same grip strength as?
Bolts of the same size
139
When is a lock washer used?
If the joint is not structurally critical
140
What is a lock washer?
The spring action of the washer creates friction
141
What is a spring washer?
A double coil spring or single coil with sharp edges. it is compressed and creates friction
142
What is a tab washer?
Two or more tabs that are suitable for a plain nut
143
Can you re use a tab washer?
No
144
What is a shakeproof washer?
a spring steel washer with slanted serrations on its internal or external surface
145
Why is there an angle of serrations in a shakeproof washer?
For the nut to ride them and cut into them
146
Can you reuse shakeproof washers?
Yes if they retain its springiness
147
Where are drilled head bolts often used?
In vibration prone areas
148
What is the wire diameter measured in?
1/1000
149
What is a minimum of twists per inch?
6-8 twists per inch
150
In critical areas where a number of bolts must be secured by wire what is the maximum number of bolts?
3
151
How are locking plates secured to the structure?
They're secured to an adjacent sort
152
What are lock plates held in place by?
Shakeproof washers and tab washers
153
154
155
Can lock plates be reused?
yes if they remain good fit
156
What are pal nuts?
They're a spring locking action nut which provides lightweight vibration proof in low profile
157
Are pal nuts designed to be with or without a standard nut?
Both`
158
Where are pal nuts idea in use?
Where frequent load changes tend to loosen conventional nuts
159
What are quick release fasteners?
They provide vibration resistance for quick and repetitive attatchment and removal of panels with minimal effort
160
What does locking and unlocking a quick release faster require?
A quarter turn or push
161
What are the two types of Dzus fasteners?
Light duty type
Heavy duty types
162
What are light duty type fasteners?
Used on box covers, access hole covers and lightweight fairings
163
What are heavy duty fastners?
Used in cowlings and heavy fairings
164
What is the main difference between the two Dzus fastners?
A grommet is used with heavy duty fastners
165
What does the airloc consist of?
A receptacle, a stud and a cross pin
166
What are the two types of airloc?
The fixed type
The floating type
167
What does the floating type consist of?
Easier alignment of the stud into the receptacle
168
What can Camloc fastners be referred to?
Quarter turn fastners
169
What are camloc designed to do?
They're designed to connect quick and easy in confined spaces
170
What helps to save time in Camloc?
Turn latches
171
What are Camlocs resistant to?
Vibration
172
The quick turn fastners usually consist of what?
A stud a washer and receptacle
173
What is a pip pin?
They're non threaded fastners allowing the rapid installation and removal of parts without tooling
174
What are the two versions of pip pins?
Locating and locking version
175
What are rung pull detect pins?
A single ball locates the pin, no positive pin. For locating purposes
176
What is a double acting steel pin?
To release the ball lock mechanism. The ring handle can be pushed in or pulled out
177
What are circlips?
A spring clip used for internal and external washing
178
What are cir clips used for?
Retaining shafts seams and bearings
179
What are used to open or compress the circlips?
Special pliers
180
What are taper pins?
Is a joint that is created for shear loads that does not allow any loose motion or play
181
What are roll pins?
They are used to provide propping for a joint where the pin is not likely to be removed
182
What is a roll pin made up of?
It is cylindrical but the ends or not joint which helps it to compress in the joint
183
What are clevis pins used for?
Hinge Pins
184
How do you remove a roll pin?
With a pin punch
185
What are clevis pins increments?
What are clevis pins increments?
186
What pins are inserted into clevis pins?
Split pins
187
What must never happen with split pins?
They must never be over torqued to make the holes align
188
What must happen if the nut fails to align with the drilled bolt hole?
Add washers until a split pin can be inserted
189
What is a key?
Formed metal that fits into cut outs
190
What is the advantage of Woodruff key?
Once it is placed in the part, it is unable to move
191
What is a square key?
They tend to move out of their slots unless placed by a locking fastner
192
What is a Pratt and Whitney key?
Once it is placed in the part it is unable to move. Also known as the Sunken key
193
What is the gib head key?
It's tapered and driven in place
194
What governs insertion depth and allows removal?
The tang
195
What does the gib head key require?
Retention in critical applications
196
What are the two self locking nuts used in aviation?
The fibre or the nylon type
197
What can happen if three threads are exposed in self locking nuts?
It can bottom out and create a stress point
198
What corrective action must you take if it bottoms out?
You must replace the bolt or add washers
199
What are low temperature self locking nuts not meant to be used in?
Temperature must not excited 122
200
What are self locking nuts held in place by?
A nylon insert
201
What are low temperature self locking nuts class in terms of fit?
Class 3
202
Self locking nuts must not be used where?
In tension only shear
203
What must be used when temperature exceeds 121?
Metal lock nuts must be used
204
What do metal lock nuts look like?
The nut has a smaller diameter compared to the boys to grip the bolt
205
When are castellated nuts used?
Class 3 shear or tensile loads
206
What does a shear castle nut have the same type thread as?
AN310
207
What are different about shear castle nuts?
They're only used for shear so are much thinner
208
What do plain nuts not have?
Castellations so can't have a split pin so must use a spring type washer instead
209
What loads do plain nuts require?
Shear and tensile
210
What is a plain nut locked in place with?
A check nut
211
What is a check nut?
A second nut that tightens it
212
What is a check nut?
A second nut that tightens it
213
213
Where are light hex nuts used?
In non structural appliances requiring light tension and they need a locking device to secure them
214
215
What class fit are engine nuts?
class 3
216
What does a plain engine nut not have?
Holes for split pins
217
What size does a plain engine nut fit?
11.1
218
When is the use if a wing nut necessary?
To remove a part frequently without the use of tools
219
What is a lock nut?
Two nuts are screwed onto the outer thread if the stud
220
What do anchor nuts do?
They're permenantly mounted nuts that enable inspection plates and access doors to be completely removed
221
What is a stud?
A shaft that is threaded at both ends but one is a long thread the other is shirt thread
222
What is the short thread?
A coarse thread and a much tighter fit than the long thread
223
When are studs used?
Where joints have to be broken frequently
224
What does a stud not have?
A head
225
What is a standard stud?
Most commonly used. They have the same diameter for the threaded major diameter and the unthreaded portion
226
When is a waisted stud used?
Where strength has to be retained but weight saving is required
227
Where is a stepped stud used?
Provide stronger anchorage and used as replacements for plain studs
228
What are shouldered studs?
Maximum rigidity is required against lateral stresses
229
What is a stud box?
A hexagonal metal bar
230
What is a stud insertion or removal tool?
The stud is started into the thread, the stud and tool turn together
231
What are tinnerman nuts?
Theyre stamped out of sheet metals
232
What are tinnerman nuts used for?
Riveted to a structure to hold screws and used to secure inspection plates
233
What is a rivet?
A type of fastener that obtains its clamping actions by having one if it's sides mechanically upset
234
What happens when a rivet is driven?
The cross sectional area increases along with its bearing and shear strength
235
How much must a rivet extend out of the material before driven?
1.5cm
236
How much does the bucktail surface?
1.5cm
237
After riveted, how much must the rivet extend?
One half the original diameter
238
What does the first part of the code denote?
The rivets organisation
239
What the second part represent?
Rivet alloying material
240
What is the third digit?
The diameter indicated in 1/32
241
What is the fourth digit called?
The length indicated in 1/16
242
How is the length of a universal head rivet measured?
The bottom of the head to the end of the shank
243
How is the head of a countersunk rivet measured?
From the top of the head to the end of the shank
244
What is the countersink angle?
100 degrees
245
What is dimpling?
Mechanically denting the sheets that are joined to accommodate the rivet head
246
When installing a countersunk head rivet, how much is the head meant to protude?
0.005 to 0.007 of an inch
247
If the head provides after firming, what can happen?
A rotary micro shaver can be used to flush the rivet head
248
What is a left hand image?
If the rivet head is allowed to protude above the metal. The rivet guns energy hits the head resulting in a stronger joint
249
What is a right hand image?
If a countersunk rivet is set with the rivet head flush with the surface, some of the rivet guns driving energy is lost
250
What Is aluminium represented as?
A
251
What is 2117 aluminium alloy known as?
AD with a dimple in his head.
Theyre always known as field rivets and have a dimple in the head
252
What is 5056 Aluminium Alloy known as?
B. They have a raised cross on their head
253
What is 2017 Aluminium alloy known as?
D. Extremely hard and have a raised dot in the centre of their head
254
What is the new version of 2017 aluminium called?
The crack free rivet alloy
255
Why must 2017 alloy be reheat treated?
They're too hard to be driven one hour after heat treated
256
How is intergranular oxidisation of 2017 Ally oxide prevented?
Its anodised before the first reheat treatment
257
How can 2017 be soft enough to be used for several days?
By putting it in the freezer below 0 degrees
258
What temp are 2017 Ally alloys subjected to when heat treated?
499 to 510 for 30 minutes and immediately quench in water
259
2024 Aluminium Alloys are identified how?
DD and two raised dashes
260
How is 7050 designated?
With an E and raised circle
261
How is Corrosion resistant steel designated?
No markings on the head and with the letter F
262
When are Monel rivets used?
Instead of CRES When their lower shear strength is not a cause of damage
263
What are Monel rivets identified with?
Two recessed dimples in their head, M
264
What are titanium rivets?
Cylindrical or partially tapered shank
265
Is heat treatment titanium rivets heat treated?
No
266
How are titanium rivets identified?
Raised T or V
267
What requires access to both ends?
Conventional solid shank rivets
268
What requires access to one side?
Special or blind rivets
269
What are pop rivets?
They're never used for structural repairs
270
What are pop rivets known for?
They're useful for lining up holes
271
What were cherry friction locks' styles?
Hollow and self plug in
272
What are cherry friction lock rivets two head styles?
Universal and 100 degree
273
When a friction lock is used to replace a solid rivet how much larger must it be in diameter?
1/32
274
What are mechanical lock rivets designed to do?
To prevent the centre stem of the rivet from falling out
275
What is the difference between friction lock and mechanical lock rivets?
Mechanical lock rivets permanently locks the stem into place
276
What are Huck loks used for?
Structural replacement for solid shank rivets
277
What are Cherry lock rivets?
Their centre stem is locked into place with a lock ring
278
What does installation of a cherry lock require?
A special pulling tool
279
What's a disadvantage of cherry lock rivets?
If a rivet is too short for application the lock ring sets prematurely resulting in a malformed shank header
280
What do removal of special fasteners involve?
Removal of the washer nut or locking collar
281
What do you remove special fastners with?
Proper sized box end wrench or vice grips
282
What is a Hi Tigue fasteners?
They have a bead that encircles the bottom of the shank
283
What does the bead do in Hi Tigue?
It preloads the hole it fills resulting in stronger joints
284
What are taper locks?
Strongest. Exerts a force on the conical walls of a hole
285
What are Hi Lites?
Same as Hi locks but made from a lighter material and has a shorter transition from the thread to the shank
286
What are the benefits of Hi lite?
Good strength to weight ratio, weight saving with no loss of strength
287
What do lockbolts conform to?
Military standards
288
What are lockbolts used for?What are lockbolts used for?
To bond two materials permanently
289
Are lockbolts heavy or leightweight?
Leightweight
290
What are three types of lockbolts used in aviation?
Pull type
Blind type
Stump type
291
How do you fit a Hi lok bolt?
The hole is first drilled with an interference fit, the Hi Lok is then tapped into the hole and a shear collar is installed
292
What do Hi lok bolts withstand?
Bearing and shearing loads
