minimum edge distance for holes in glass

[agreeive?fish]

Hello all,
As stated in the title what is the minimum edge distance for holes in glass....

the glass is either 1/4 or 5/16 inch(my eye sight aint that good). it is a 29g wally world tank and iam wanting to install 2 (two) 1 1/2 inch (one and onehalf inch) bulk heads ... one for drain and one for return... on oposite ends of the tank on the back pane as high as possible. This is a practice tank that i will run for about 6 months(no fish or anything just water in garage) before i drill my 200g...thanks for any information.

[30mini]

The rule of thumb is one diameter away for the hole that your drilling. 1.5 is preferrable, but if you can only do 1, that should be fine

[Scott M]

I shoot for a minimum of 1" from the trim to the edge of the hole.

[boviac]

be warned. smaller tanks have been known to have all sides as well as the bottom tempered. YMMV. Good luck!

[agreeive?fish]

To all thanks for the replys

boviac... thanks for the heads up...but if it breaks it breaks its just a cheap wal mart tank..easily replaced if needed or desired..