The ThruLOK system is a screw that replaces a carriage bolt by connecting posts, beams, carrying beams, and other lumber components. It is used as a wood-to-wood fastener that meets code for deck building and new construction.
The ThruLOK system consists of three parts: a screw, a washer, and a nut. At the tip of the screw, there is a specially-designed paddle point that allows the screw to cut through dense lumber without creating a split. At the head of the screw, FastenMaster has included a hex head that allows for fast installation. A galvanized washer helps evenly distribute the tension created by the screw, while a ThruLOK nut has teeth to grip into the wood, as well as paddles that allow the system to be tightened without a wrench or socket.
Installation of the ThruLOK system requires fewer steps than a carriage bolt. To install, builders simply place the tip of the ThruLOK screw in the appropriate location and drive it into the wood until the washer is tight against the lumber.
After the screw is in place, the nut is fixed on the opposite end. Simply hold the nut and use a drill to tighten the system into place.
In this comparison video, ThruLOK requires only 11 seconds to install, while the carriage bolt requires a full minute.