artesc

Ok, this is probably going to sound like a stupid question, but here it goes...

I put a new chainring on; it is on a singlespeed crank and I got chainring bolts for a singlespeed. However, as I try to tighten the bolts down, the back (that holds the everything together and the female, threaded part) simply keeps on turning and doesn't tighten up to an acceptable tightness. I don't have a wide enough flathead screwdriver to hold it in place, I tried holding it with needle nose pliers as well as simply putting pressure on it with a regular screwdriver.

How am I supposed to keep it from turning? Is there a special tool that's sold? I've searched, but I can't seem to find anything. Do I need new chainring bolts? Is there some trick to do it so I don't have to buy a special tool. What? Thanks.