With coarse threads that dig in, these screws secure posts and beams in outdoor and wet environments. They won't degrade from moisture or chemically treated wood, such as ACQ-treated (arsenic-free) lumber. The hex head's six contact points keep sockets in place to avoid slipping and stripping on the drive. To tighten, use a wrench or six-point hex socket. Also known as lag bolts.

Drill a pilot hole slightly smaller than the screw to prevent splitting. Length is measured from under the head.

A built-in flange protects surfaces from splitting and pull-through by spreading pressure over a large area. These screws are often used to secure wooden posts and beams because their coarse threads dig in. The hex head's six contact points keep sockets in place to avoid slipping and stripping the drive. To tighten, use a wrench or six-point hex socket. Also known as lag bolts.

Drill a pilot hole slightly smaller than the screw to prevent splitting. Head height includes the flange. Length is measured from under the flange.

Also known as hanger bolts, use these studs to hang, mount, and fasten parts to wood structures. Install them with a stud driver, or create wrench flats by threading two nuts onto the stud and jamming them together.

A built-in flange protects surfaces from splitting and pull-through by spreading pressure over a large area. These screws won't rust, so you can use their coarse threads to secure posts and beams outdoors. They also won't degrade from chemically treated wood, such as ACQ-treated (arsenic-free) lumber. The hex head's six contact points keep sockets in place to avoid slipping and stripping the drive. To tighten, use a wrench or six-point hex socket. Also known as lag bolts.

Drill a pilot hole slightly smaller than the screw to prevent splitting. Head height includes the flange. Length is measured from under the flange.