Not really sure why you would need a special type drill Kevin? Am I right to think the material will be either brass or mild steel?All, broke off a tap in threaded hole on my 1 hp Famous. What's the best drill bit to use to attempt to drill it out? Thinking a diamond tip bit would be best. Any thoughts appreciated. Size is about 3/64" - 1/8".
Duh?..i mistook the question to be about a valve type tap!Okay, here's my method that works sometimes if all else fails.
Pounding lightly using a piece of soft steel as a punch (so as not to shatter the tap), try to loosen it a little. Then with either a forked tap extractor or a small punch, try to rotate it a little either way. If you're lucky, you can get it to move. Keep the hole cleaned out with air and coax it out. A lot of patience helps.
Been there - done that.