Abstract: A tie rod for spanning a duct interior to join duct walls bounding the duct interior, that can be simply and inexpensively fabricated from sheet metal or other suitable material, including automatically, securely fastenable quickly and easily to the duct walls, often by one person, and which can be configured to be nestable for efficient storage and shipping, of elongate construction for spanning a duct interior, with a transverse attachment flange or flanges that can be pre-bent or bent onsite at the installation location via special bending features to snug to a duct wall, and include holes for threadedly receiving fasteners, having a shape and size to reduce fastening torque, with a two attachment flange configuration that resiliently self retains the fastener against loosening from vibration and other forces.

Abstract: A tie rod for spanning a duct interior to join duct walls bounding the duct interior, that can be simply and inexpensively fabricated from sheet metal or other suitable material, including automatically, securely fastenable quickly and easily to the duct walls, often by one person, and which can be configured to be nestable for efficient storage and shipping, of elongate construction for spanning a duct interior, with a transverse attachment flange or flanges that can be pre-bent or bent onsite at the installation location via special bending features to snug to a duct wall, and include holes for threadedly receiving fasteners, having a shape and size to reduce fastening torque, with a two attachment flange configuration that resiliently self retains the fastener against loosening from vibration and other forces.