abstract
architecture
background
bolt
build
business
close up
connection
construction
engineer
engineering
equipment
factory
fixing
hardware
industrial
industry
infrastructure
iron
joint
labor
machinery
manufacture
manufacturing
material
mechanic
mechanical
metal
nut
painted
pipe
pipeline
plant
production
repair
riveted
rivets
screw
screwing
steel
strength
strong
structure
technology
texture
thread
tighten
tool
tube
work
workplace