Truss plates allow for dimensional lumber to be fastened together in plane in any number of configurations to create a truss using the properties of triangulation. Truss plates come in many sizes and are typically square or rectangular with multiple teeth “punched” in the manufacturing process to give them gripping strength when pressed into wood. They are manufactured with steel that is protected with zinc or zinc-aluminum alloy coatings or their stainless steel equivalent. They are designed to laterally transmit loads in wood.
Each component manufacturer has its own manufacturing methods but a majority of manufacturers utilize one of two methods to press truss plates into wood. The first method is a series of roller presses, the first a gantry type with 18-24” rollers that travel along a table to initially press the plate into place. It is then sent to a conveyor system and through a similarly-sized finish roller that completely embeds the plate. The second method is any variety of hydraulic presses that can be C-clamp pressed in place including a larger hydraulic press that travels on a gantry and presses plates into place using a large metal head. Regardless of manufacturing process, each plate is required to meet quality control tolerances for plate embedment, rotation, defective or rolled teeth, and other criteria.
Truss plates are required at each truss joint and splice. They are placed on both sides of the truss, essentially sandwiching the joint and splice. Plates can be rotated and shifted to increase surface area and maximize holding power. In some instances, like heel conditions, multiple smaller truss plates can be used to transfer forces opposed to a larger plate, improving the economic inputs of the truss.
A variety of manufacturers produce truss plates which on the surface look very similar. In reality they are a highly engineered product each with unique characteristics. Each plate manufacturer has a mechanical die that forms the teeth when punched through the metal creating a twist that adds to the strength and makes each truss plate brand unique. In addition to traditional truss plates, these manufacturers also produce unique products such as a hinge plate that allows for unique truss manufacturing and transportation capabilities.