Fastening methods Flashcards
4 different types of fastening methods
Riveted
Bonded
Welded
Threaded
Selection factors for fastening methods
load characteristics ease of removal vibration corrosion material cost tooling access environmental maintenance considerations
Selections factors for head styles
torque to be applied
access to head
recessed or raised head
dirt ingress
Specifications associated with threaded fasteners
material and grade coating thread type and size thread length head shape
Purpose of fine
greater range of fine adjustments means more grip area per unit length
Purpose of coarse
better load distribution in soft materials
increase in speed of linear movement per revolution
The importance of correct torque
ensures correct tightness for application
helps prevent fastener loosening under load/vibration
ensures fastener loading is not exceeded
Friction locking devices
spring
shake proof washer
lock nut
stiff nut
Physical locking devices
tab washer
split pin
Allowance
amount of shank which protrudes through other side of hole
Clearance
difference between rivet diameter and hole diameter
it’s important to reduce stress and allow correct placement
Solid rivets
require good tooling access to both sides of joint
for a given diameter and material, a good cross-sectional area is required to resist shear loads
Blind rivets
only require tooling access to one side of the joint
Blind rivets measurements
head diameter head depth shank length shank diameter clearance hole size max riveting thickness
Structural joints main considerations
loading fastener type material access aesthetic property
