Bolts Flashcards
Name three standards for fasteners
American Standards, AN, MS, NAS
European Standards, NSA (NATO standardisation agency)
Aircraft Manfcts standards. (BAC, FON etc)
List the types of American Standard threads
ANC, American National Course ANF, American National Fine ANEF, American National extra fine ANP, American National pipe. 60 degree pitch
List the United Standard threads.
UNC, Unified National Course
UNF, Unified National Fine
UNEF, United National Extra Fine
60 degree pitch
List the British Standard Threads
BSW, British Standard Whitworth BSB, British Standard Brass BSP, British Standard Pipe BSPT, British Standard Pipe Taper. 55 degree pitch
Describe SI Metric
European metric thread, 60 degree pitch groove = 2x lands
List the five classes of fit
- loose fit.
- free fit (wing nuts)
- medium fit (hand tighten, most common in aviation)
- close fit (requires a wrench)
- tight fit (requires a wrench)
Explain call out and give example
Call out is the code given to a bolt to describe its characteristics.
e.g. AN5H-7A AN (Airforce, Navy Standard)
5 diameter in 1/16” therefore 5/16” diameter.
H, hole drilled in head
-7 length in 1/8’ therefore 7/8’ long
A, Absence of drilled hole in shank.
Give exceptions for callout codes
NAS, if the dash no. is even, length in 1/8”
if dash no. odd, length in 1/16”
lengths over 1” still no of 1/8” i.e. 11 = 11/8” or 1 & 3/8”
AN lengths over 1”, 11 = 1 1/8’ 14 = 1 4/8”
NSA length and diameter are 1/16”
What is a standard bolt and how is it identified?
Hex head. Grip length and thread length.
AN length is overall. Others are from the grip length only. Identified by markings on the head.
Standard bolt has a star or Asterix on the head. Made from Cadmium-plated nickel steel.
How is a close tolerance bolt identified and what is the tolerance?
It has a cross within a triangle on its head.
+0.0 to - 0.0005”
What is different about an internal wrenching bolt?
It has an internal allen key head, is much stronger for high tensile loads. Has a radius between the shank and the head therefore requires a special washer between the bolt and the material.
Describe a bolt with two dashes on its head
A DD2024 aluminium standard bolt.
Describe a clevis bolt and its use
It has a round head. For use with shear load applications only. Measured in 1/16” for length and diameter.
How is a fillister machine screw identified?
It has a round head with a screw driver tightening socket. Full length thread.
Explain these bolts: One dash, Two Dashes, Star or asterix, Triangle Round head
corrosive resistant, 2024 aluminium alloy Cadmium plated Nickel steel close tolerance Clevis bolt
