Extracting broken bits: When a screw extractor, tap or drill bit breaks, leaving one end buried deep into an assembly, it can be a real hassle. The best initial advice is not to rush in, because removing hardened steel from softer surroundings calls for a mix of patience, skill and luck. Here we look at an admittedly brief selection of extraction methods, one of which should help remedy even the most stubborn of metal-in-metal cases