I am a single mom and I have not asked my dd's father for any money. I have contact with his parents but don't talk to him. I am afraid of his temper and worry that he might go nuts if I ask him for money any way I moved to an other city to be safe from him and it has been over 3 years now lately I have been thinking about asking for child support, the thought is real frightening ~part of me just wants to leave it alone but then I think what if he has changed or maybe he won't come after me for asking does this sound paranoid or is it worth the risk?

If u have contact with his parents, and their reasonable, caring grandparents, why not talk with them about it...have them mediate things.
You have a right to expect him to help with CS. If u can talk to them openly about your concerns this might be the best place to start.