I'm trying to drill a 1.25 - 1.5" hole in a granite countertop which is already installed. This will be used for a water filter faucet.
Now from what I looked at this drilling is not trivial. The thickness of the top is about 1.3 - 1.4" already so that's another challenge.
Would you guys recommend I leave this to the pros? What kind of place would give me a good price for drilling a single hole in this countertop without having to remove it? I'm also afraid that drilling too close to the sink location (the sink cutout) will result in me damaging it if I attempt it.
Call a granite fabricator and have him do it. This requires diamond coring saws with the correct RPM's and one should be able to read the grain of the stone in some cases. There may also be reinforcing rods embedded into the underside that must be avoided. ABSOLUTELY DO NOT USE a percussion drilling machine on the granite.
Some plumbing companies can also provide this service for you.