Abstract: A magnetic assembly is used in wells that are lined with a metal casing so as to attract and collect resulting metal debris after perforation of the metal casing by a perforating tool. When the perforating tool was activated in the past, the metal debris typically fell downward inside of the metal casing and needed to be retrieved by a flushing or similar procedure. The present invention involves attaching a magnetic assembly to the bottom end of the perforator tool to collect the metal debris as it falls after perforation of the metal casing. The magnetic assembly includes a steel pipe filled with spaced magnetic discs, and also includes a guide shoe on one end of the pipe and a thread adaptor on the other end. The guide shoe facilitates insertion of the magnetic assembly into the mouth of the well casing, and centres the assembly once inside. The thread adaptor is used to attach the magnetic assembly to the bottom end of the perforator tool.