Drilling a 55 Gallon

[Shabe]

Has anybody drilled the back of a 55gal tank? I know 99% of the bottoms on 55s are tempered glass. I have a spring project. I have 8 4ft tanks to setup and wanted to do a central system. Unless anybody wants to trade 8 55s for 4 125s :colrface:

[chris1932]

I take two pieces of 1" thick wood one cut to about 12" square for the inside, and another for the outside. This reduces glass deflection. Drill a tight fit hole on the outside piece of wood that you can butt up to the frame. This puts the hole in the same spot on each tank. Wet the wood and place it on the inside pane of glass if it is nice and flat it should almost stick by itself. Place the outside wood where you want the hole and clamp it up. I have a hose reducer that gets down to 1/4" poly tubing "Lowes" with a valve on it to control the amount of cooling water. I also added two dowels to the outside block of wood that are at a 90 degree angle to the glass, this lets me know if I am keeping straight. If you drill crooked you will crack the glass. Go slowly, Stop often, let the drill set the pace. Ive drilled about 40 tanks and no matter how good I think I am getting I break about 1 in 15.

[Shabe]

Thanks for the advice. I actually have a workbench drill press I will be using.

What I was more worried about is if the sides of the tank were tempered.
I never heard anybody mention drilling a 55gal tank.