機器
agricultural
antique
closeup
cog
cogwheel
dirt
drive
engine
engineering
equipment
force
gear
gearing
gears
grease
green
grinding
grunge
historical
industrial
industry
iron
isolated
jump
machinery
mechanical
mechanics
mechanism
mechanisms
metal
old
part
power
precision
quality control
reduction
robust
rust
shaft
steampunk
steel
sturdy
technical
technology
transmission
wheel
workplace
workshop
worm