router bit

im going to be building a short and tall overflow box, sort of a coast to coast, but it wont go all the way to the ends of the tank, just in the center. but to the point, how do you setup a jig to cut the vents for the top of the overflow. how far below the edge of the aquarium should...

I was wondering if anyone out there had any experience cutting 1/2" cast acrylic using a cnc machine. I am wanting to cut an aquarium and have access to a Gerber Profile 408 machine (for those of you that are familiar with Gerber). I was needing to know the proper bit, speed and rpm. I am...