Quote Originally Posted by lowslowbenz View Post
Screw extractor.

See here: Screw extractor - Wikipedia, the free encyclopedia

Most hardware stores sell a set.
hey, nice! I'm from the city of pines, and hopefully some hardwares here sell that too. This is one option, like the glow plug tip removal kit. The broken tip has a dm approximately 4mm. I wonder if they have a size for it? tnx