[oh'mike]

That's not good---try drilling along side the broken tip perhaps you can pry the tip out before the head is unusable.

 

[WirelessG]

How far in is the screw? Can you get a set of vise grips on it? Can you grind the sides of the screw head flat to get a better grip?

 

[djgrant]

I'll check and give it a go, thanks.

 

[Thurman]

Remember that the Robertson tip is stuck in the screw head in the diredtion in which you were turning it--sounds like you were attempting to loosen the screw. This means the tip is stuck in the CCW postition. Try using something real small but hard along with a small hammer to move the tip in the clock-wise (CW) direction. Don't beat it, just give it little "love" taps. I'm betting that this will knock it loose and you will be able to remove it easily.