A large, heavy-duty wood screw designed to be driven with a wrench or socket rather than a screwdriver. Despite the name, it is technically a screw because it cuts its own mating thread in wood rather than passing through a clearance hole to accept a nut.
Heard on the job
Grab a half-inch lag bolt to anchor that bracket to the stud.
Insider tip
Engineers and catalogs call this a lag screw, but field workers almost universally say lag bolt.
Also heard as
- Coach screw
- Lag screw
Do not mix it up with
- Bolt: A bolt is designed to take a nut, while a lag bolt cuts its own thread into wood.