aga 20 high

is it just the bottom that is tempered or is it the whole i tried drilling two and as soon as the hole saw got to the other side it cracked i was told they aren't tempered but the glass says different

 

Did it make one or two cracks or did it make a thousands of cracks covering the whole piece of glass? If it was tempered then it would crack the hole piece of glass into thousands of pieces.

I doubt the side pieces are tempered. The hole saw tends to bind up as it is exiting the back side of the glass. Finishing the hole without cracking is the hardest part. I did the same on the first 10g I drilled. You need to go really slowly and don't apply any pressure.

 

i know i have drilled a bunch of tanks all sizes of holes in all thicknesses of glass this just boggles my mind i don't see any where that is it or isn't tempered but it just keeps cracking it was a crack about 2'' inches long i drilled into a tempered tank once with no insane cracking and i had the most problems with ten gallon tanks the thicker the glass the easier it is

 

any thoughts

 

Unless the glass is tempered, you really shouldnt have any problems, are you taking your time? How old are your bits and what is the wear on them?