making a hole in a HARD plastic lid? help

hi, i have a nice carboy that i've used before with an improvised plastic bag cover. however this time around i'd love it if i could use the nice plastic lid that came with it and just stick a bung/carboy in it.

the bottle is PET, the lid seems to be labeled "PP", which is polypropylene? it seems very hard, here's some photos http://i.imgur.com/H2Ayf.jpg and http://i.imgur.com/DwEJ3.jpg

i have no real tools, but i can buy some cheap cutting implements if need be. just wondering if anyone has any suggestions for cutting a hole in this? it feels like if i tried cutting into it with a knife the plastic would crack and not be usable. it's probably about 5-7mm thick also... any ideas? or even any totally alternate ideas for a good extra wide mouth carboy cover?

Why not just drill a hole small enough for the airlock stem and put a rubber grommet in the hole to seal around the airlock?

There has to be a way you can access a drill or take it to someone who does and have them do it for you.

If you try and cut it, I predict a laceration in your future.

Cutting manually will leave you with an unsymmetrical hole which will not fit a bung properly. What you need is a drill and a 1 inch hold cutting attachment. I bought one from home depot recently for under 10 bucks. Borrow a drill if you need to. The hole cutting attachment will have a drill bit in the center so use that to drill a pilot hold and then take your time going through the plastic so that you don't heat up and melt the plastic. You may need to remove some rough plastic bits after with an 'exacto' knife manually.

I did this recently when making a bottling bucket by drilling the hole for the spigot.

Go to Home Depot and buy a spade bit like this one. http://www.homedepot.com/Tools-Hard...splay?catalogId=10053&langId=-1&storeId=10051. If you don't have a drill buy one like this http://www.homedepot.com/Tools-Hard...splay?catalogId=10053&langId=-1&storeId=10051. Put a piece of wood on the opposite side of the lid when you drill it so when the bit makes it through the plastic it will go into the wood. this should help prevent any splitting or cracking of the plastic.

thanks guys, yeah im gonna need to bite the bullet here and get someone to drill. i would definitely go to home depot and find something, but im in east asia and they really don't seem to have hardware stores at all. that's what makes all this so difficult. i'm probably just going to write out translated instructions and offer a few dollars for some old man to drill a hole in the thing and see how it goes.. i'll try to post results.