TAPS
Some of the guys are dead on... shatter it! EYE PROTECTION!
Heat DOES NOT change the hardness of a HSS tap enough to benefit you. take a center punch and whack it ! Resharpen your punch when your done.
On taps, the less flutes the better, thread depth to root dia. ratio determines how fragile it is... next time you can "cheat" a bit and go a tad larger on the tap drill size. Also get a block of brass and drill (on a drill press) tap drill sizes and tap clearance sizes and you will have a guide to drill and tap with, nice and square to the material being drilled and tapped... less chance of breakage. anti seize is an excellant tap lube. Some will try motor oil... FORGET IT!! If you can find "Rapid Tap" fluid you would have to try to break one!
Mike