Broken tap

[chester]

I had broken a 3ba tap half way through a 2" square by 5/8" thick mild steel bar with about two hours work on it, it would not come out with a centre punch so i heated it up with a gas torch as hot as i could which was dull red and let it cool down slowly.When it was cool i found a 1/8 tipped drill and put the pillar drill on it's slowest speed about 160 revs with a fair amount of pressure and it slowly came out as a black dust.The thread cleaned up with another tap, have i just been lucky or is this possible with carbon steel taps.

[paul]

I'm glad it worked out for you!

I suppose your HSS drill bit is harder than the carbon steel tap.

Conventional wisdom is you can't remove HSS with HSS but I've managed to drill out (well more sort of push out) a broken 1.5mm bit using a larger bit but it took ages!