Single-speed chainring bolt tool

so having just finished building my bike (fixed gear), everything is fine except ONE of the chainring bolts is a bit loose and creaks when i pedal. not in danger of coming out but we all like the beauty of silent riding.
so does anyone have a tool with prongs to hold the non-allen-key bolt still while it's tightened? otherwise it just spins! i know there is a tool for it, but i can't seem to find it and as i only need to use it for about 30 seconds i thought i would see if anyone has it and can lend it to me?
cheers,
henry

5p piece and a pair of pliers, failing that I have the tool if you need it I am in W10 or may be at Wests this week.

I use a padlock Key clamped with the keyring part out in a set of mole grips.

Used to use the park tools one that all the evens have in their mechanics tool set (Ma3k used to work there), it hooks nicely over the chainring so you can tighten the bolts a lot easier - went to evans to buy one and they kept trying to sell me this shit screw driver one that just doesnt work! I explained that they have one in the work shop which is a lot different could I order one like that.. after a few min of explaining the one in their workshop is different he went down to get it ..sure enough it was a different and said oh right ill order this ..park do not sell it unless its in that pro mechanics kit for £1500..

small key or 5p like diable says put it in a set of mole grips, it will tighten up to a point and you then dont need to hold it in place to continue tightening

Ive just noticed the sjs ads are returning that icetools chainringbolt tool dont buy it!

click pic

that's a silly pic, those look like a set of 75's and the rear bolts have teeth so it bites into the back of the crank arm, therefore does not need a tool to tighten/remove.

but, that is the proper tool for the job.

Wow, didn't know there was a tool for that - I used an allen key in the front & a knife across the back!

The OP should just spend the £6 and buy his own. You'll need to buy tools one day.

http://www.wiggle.co.uk/p/cycle/7/LifeLine_Chainring_Nut_Tool/5360031521/

I usually just try and catch it out by a number of swift movements!

I bought the apparently wrectched icetoolz £3.50 modified screwdriver and it worked just fine, though did need some pliers to hold the blade on a couple of bolts. I'm in Stockwell if you'd like to borrow it.