Drilling out a chainring bolt?

Have UTFS'd but couldn't see anything on this...

Converting an old 80s peugeot to a beater. Its got a double chainring and I reckon I can just use the smaller ring so I was hoping to remove the bigger ring. 4 of the chainring bolts came out easily but the last one just spins. I've got the proper chainring nut tool but the grooves in the nut are now totally chewed and I can't get enough purchase. So.... is it possible to drill it out? Anyone done this? If so, what size drillbit is best? And can it be done without removing the cranks? If worst comes to worst I'll just leave both rings on for now, but would rather not... Ta!!

Sounds a bit dodgy tbh, but I would say take the cranks off the bike, then pick a drill bit just a tiny bit too big to fit into the bolt. Then when you have drilled through with that one pick the next size up. It would be a shame to kill your cranks for the sake of this bolt, so go easy! 'Measure twice cut once'.

Cheers. Just UTFgoogle'd and found a few alternatives here:

http://www.bikeradar.com/forum/viewtopic.php?t=12661423&postdays=0&postorder=asc&start=0

Will try some of these first I guess...

Sounds a bit dodgy tbh, but I would say take the cranks off the bike, then pick a drill bit just a tiny bit too big to fit into the bolt. Then when you have drilled through with that one pick the next size up. It would be a shame to kill your cranks for the sake of this bolt, so go easy! 'Measure twice cut once'.

It isn't even remotely close to precision dentistry to drill out a chain ring bolt. I have had to do this to remove aluminum bolts, since they strip so easily. Of course aluminum is a bit easier to drill through than steel, but the principle remains the same. Might as well leave the crank on...

If the nut is just turning (it is), will drilling the bolt not just make it spin really fast? Or will it still do the required damage eventually?

It isn't even remotely close to precision dentistry to drill out a chain ring bolt. I have had to do this to remove aluminum bolts, since they strip so easily. Of course aluminum is a bit easier to drill through than steel, but the principle remains the same. Might as well leave the crank on...

If the nut is just turning (it is), will drilling the bolt not just make it spin really fast? Or will it still do the required damage eventually?

Place it on a bit of wood that will help stop the thing spinning oh and don't use the drill on full speed as you may end up spinning the chain ring across the room decapitating anyone close by.

iv done it before and it worked fine, just dont use a drill bit thats bigger than the hole in the crank