I had an 1/8" BSP grub screw stuck in the front block of my timmy. The Hex was completely rounded and things were looking grim. Managed to shift it using a special snap on tools ratchet bit, after first heating block in boiling water to expand it.
The snap on tool was similar to an 'easy out' with a spiral flutes that cut into the the hex. Anyway it saved me a trip to an engineering shop to get it drilled or burnt out - so was well happy.