door - drop
- double cooling bed
- double crystal spectrometer
- double descaling header
- double draft bull block
- double duo mill
- double electrode-arc welding
- double filter
- double gate
- double head blowpipe for edge preparation
- double hexagonal pyramid
- double hopper
- double image
- double logarithmic diagram
- double melting
- double mixing screw
- double mixing worm
- double pick-up tongs
- double pressed and sintered blank
- double pressing-and-sintering cycle
- double quenching
- double riveted
- double roasting
- double rolling
- double sampling
- double screen
- double shear line
- double shear steel
- double shrinkage
- double silicate
- double silk covered
- double sintering
- double skin
- double skip
- double slip
- double take-up
- double takeoff
- double tempering
- double tetragonal pyramid
- double torch
- double two-high mill