barb
carving
claw
clockwork
close up
cog
cogs
cogwheel
connecting
corrosion
device
gear
gearing
gray
grease
helical
helix
industry
iron
lubricant
lubrication
machinebuilding
machinery
macro
mechanics
mechanism
metal
metal surface
metallic
notch
old
pattern
pinion
prong
rust
rusty
screw
screw drive
screw thread
spiral
surface
technology
texture
textured
thread
tooth
transmission
wheel