I was tapping a blind M3 hole in some cast iron and broke the tap. It's part of a screw hole pattern for a cover strip to go on the mill table, so no moving away a few mm and starting again (and Murphy's law says it is always the last hole in the pattern that causes problems)
The standard textbook solutions don't/ won't work (I wonder have they ever?)
To add a degree of difficulty, the hole is horizontal.
I think my only solution is going to be drill a couple of holes next to the tapped hole and wiggle the broken piece out then plug and re-tap in the plug. Any other less destructive suggestions before I get stuck in?
(Sigh. Last job of the day too)
Michael
The standard textbook solutions don't/ won't work (I wonder have they ever?)
- Grab the sticking out piece with some pliers and back it out - yeah, that breaks off too.
- Using a centre punch, tap the tap on the flutes until it backs out - works until the piece being tapped breaks as well...
- Weld a piece of rod to the end of the tap and wind it out - weld a rod onto a broken M3 tap below the metal surface???
To add a degree of difficulty, the hole is horizontal.
I think my only solution is going to be drill a couple of holes next to the tapped hole and wiggle the broken piece out then plug and re-tap in the plug. Any other less destructive suggestions before I get stuck in?
(Sigh. Last job of the day too)
Michael
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