A system for insulating the walls of furnaces and other heated structures with ceramic fiber insulation including an improved insulation anchor. The anchor includes a pin which is attached to the furnace wall such as by stud welding with the pin having an elongated aperture at its outer end. A retaining rod extends through the aperture and into the adjacent ceramic fiber modules. The rectangular shaped rod includes an improved means for locking the rod in the aperture which comprises a crimp at about the midpoint of the rod. This provides a narrow section of the rod which permits the rod to be turned in the aperture and locked. The crimp method of forming the narrow section does not remove any metal from the rod and does not weaken the rod.
