bolt
center
cheap
crisis
defect
depression
design
drilling
eventual
expectancy
fail
failure
fastener
faulty
fracture
frustrated
frustration
hole
industrial
industry
iron
life
maintenance
mechanical
metal
metallic
metalwork
nut
over
repetitive
replacement
risk
rotate
sad
safety
screw
shear
snap
steel
stress
stressed
support
tear
threaded
tighten
tired
torque
twist
twisted
wear