Bore Hole in Granite

I have a two 3" granite surface plates that I use for a turntable stand. I recently found a new bearing that is taller than the stock one and would like to bore a 2 inch diameter hole in the lower plate. The original cut-outs were done by a water-jet machine but transporting the plate is difficult and I'm not sure if they can do it without a CAD drawing anyway. Any opinions as to the feasibility of a DIY solution? The hole doesn't have to be perfect. It is just for clearance. The hole would go in the second picture basically in the center there the heaters meet.
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I'd suggest diamond core bit and suitable drill.
They can be hired (including the bit) though a 50-is mm bit is not too expensive if you have a suitable drill.

You could test drill with a normal masonry bit then chain drill but it would look unsightly.
 
Getting the base back up the stairwell, into a vehicle and to a water-jet provider will be difficult hence the question.

The heater is to warm the motor and bearing - shortens the speed stability problems when in a cold basement. Works fine really. Been working for a number of years.
 
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Just ignore them. It always amazes me to see, although being a DIY-forum, how people always line up
to shoot down things, they never have seen or experienced before. Happens in almost every thread, and often by
the same "very helpful" people.
Congrats to you for finding a way to keep the old "thick oil bearing" at a decent, constant temperature, no matter
the surroundings. (y) (y) (y)
Just needed to get this of my chest. Unfortunately, I have no experience in drilling in stone materials, so won´t try.
Good luck with the project ;)
 
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Rent a core drill....... but I gotta warn you, if you can't move a surface plate, you're not going to like moving a core drill. Having said that have several 18" x 24" x 3" granite surface plates for equipment stands. Once strapped to a hand truck they go up and down stairs pretty easily. As for example this one under a sub-woofer
 

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Machining wet is not all that tough. You need a recovery pan that the granite will sit in, an overflow tank that a suds pump sits in. and some water born surfactant., maybe a cheese-cloth strainer and some way to manage the flow. The OEM coolant delivery on my lathe, milling machine and surface grinders are a little more elegant in execution, but certainly not more complex.

Cutting fluid systems are as much about swarf control and air quality management as cooling

Breakage happens when you lose control of expected tool or work kinematics. Which is to say: A hand drill is potentially problematic.