Drilling/Filing Glass for bong
you can use a normal drill bit , just start tapping on the glass ( tap round and round the area you want the hole ) with it and it will slowly chip ( powder ) away the glass , takes a bit of practice but its do-able.
iv done it with beer bottles and coke bottles, takes about an hour or so but once you start the hole and get it close to the size you want get a small half round file and finish off , but be careful if you get to carried away it will crack.
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