door - drop
- double two-high rolling train
- double water glass
- double-acting hammer
- double-acting steam hammer
- double-action die
- double-action drawing
- double-action forming
- double-action mechanical press
- double-armature drive
- double-bar-and-yoke method
- double-barrel
- double-barrel mud gun
- double-beam oscilloscope
- double-bell distributor
- double-bell top
- double-bevel butt groove
- double-bevel groove weld
- double-bevel T
- double-bevel tee butt weld
- double-branch gate
- double-bricking
- double-chamber furnace
- double-compression method of ramming
- double-crystal X-ray goniometer
- double-current furnace
- double-curved crystal camera
- double-deck block
- double-deck machine
- double-deck table
- double-double iron
- double-electrode arc
- double-end shank
- double-ended cantilever bridge
- double-exposure radiography
- double-faced hammer
- double-faced pattern plate
- double-fired reheating furnace
- double-flanged butt weld
- double-flash evaporation
- double-focusing spectrograph