max, I'd need the inside diameter of the existing screw hole so we can size a standard size bolt. It is no trick to retap existing threads to a slightly smaller size (provided the strength of the new threads is not critical as in your hanger case). The diameter and depth of the screw head hole is needed, too. Do you know anyone with a caliper or a fairly complete set of drills? Drills are accurately made and can be used as gauges.