screw down(redirected from screwed them down)
To affix or secure something to some surface with screws. A noun or pronoun can be used between "screw" and "down." The desk kept sliding all around the room, so I finally just screwed it down to the floor. Make sure you screw down the control panel really securely—we can't afford to let any moisture get in there.
screw something down
to secure something to the floor or a base by the use of screws. You had better screw these seats down or someone will knock them over. Please screw down the shelf.