Join standard-sized steel and cast iron pipe flanges—these kits come with the screws and nuts in the right size and number to match the bolt holes. The screw heads and nuts are 10% wider than standard hex fasteners, so they spread force over a larger area, and you can tighten with more torque. For a complete connection, you’ll also need a gasket. All fasteners meet ASME specifications for dimensions and ASTM specifications for material quality. Screw length is measured from under the head.

Grade L7 steel fasteners are treated and tested to perform in low temperatures according to ASTM regulations. Even at -150° F, the screws in these kits stand up to impact since they don’t become brittle in the cold. They’re twice as strong as those in the other kits. They’re best for dry environments, since moisture will cause them to rust. They require little surface prep before applying a finish, so you can apply your own paint or coating.