Can a non-professional drill holes in a granite countertop?

Question

I recently bought an under-counter kegerator and need to have some holes drilled in the granite countertop for the tap. The template and mount has 1.75" hole in the center (to run the beer lines) and then 4 small 3/8 holes around the center hole where bolts are placed to secure the tap down to the kegerator.

I called our granite installer and they want $200+ just to come drill the holes. Looking online, you can get Diamond Core Hole Saw Bits for $40, and smaller diamond bits for the screws for around $10. Obviously this is cheaper, but can a my standard corded Rigid drill (not VBR or hammer) handle this? Wonder what the risks are in chipping the granite? Some people recommended putting a ice cube in the bit to keep it cool and emulate a wet drill. What would be a technique to get the bit started, so it does not move when making its first cut into the stone?

Any other tips?

Answer 1

You can absolutely do this yourself with a powerdrill and 21 dollar diamond hole saw from HD. For a standard faucet hole, you need a 1 3/8" diamond hole saw. I ended up not only drilling the faucet hole, but laminated the edge to double the thickness, polished with a diamond pad, and installed an undermount sink. There is no doubt that this is a risky DIY project if you don't research how to do it properly. But I learned through online videos and resources, then practiced on the excess portion of the slab. If you would like to see what I did, search for "Thrifty Tani" on youtube. I shared my experience my videos. He'res a link to the videos How to drill a faucet hole: https://www.youtube.com/watch?v=bFWvVzlGF4Y&t=5s

Answer 2

I am a granite top fabricator, and every time I drill a hole in granite or marble, it always scares me. I think, "what if I crack this top by making the slightest error; I better pay attention and take my time!" Because the slightest error can break your stone top; even with experience it is nerve racking.

First you need a hole saw guide. Cut a guide hole with your hole saw out of a scrap piece of ceramic tile or a thin 1/8" to 1/4" piece of wood and clamp it or have someone hold that with two hands firmly. With this guide, start your hole dry until you cut down about 1/16" to 1/8 into the stone. Then, remove guide and now you have your starting guide to finish your cut. Cut slow and have some one with a water bottle applying water at all times. Though, put a sponge on both sides of the bit so you don't make a mess. If you already cut out your plywood, be careful when you get to the end of drilling your hole because you can easily plunge your drill through the hole, slamming the drill onto the counter and breaking your top. Remove your guide bit on the hole saw and pre-cut your plywood with a wood hole saw with guide bit.

Not to many people are successful their first time without a pro by their side so good luck! Or you can keep calling granite guys for a better price.

Answer 3

Alignment, temperature, speed. All critical in cutting stone. A drill press or alignment jig would be better than just a handheld drill (and definitely not a hammer drill) and a constant water stream and slow speeds are necessary. At some point you are spending on tools close to what the stoneman wants.

DIY is possible, but this is the kind of job I would pass on and call in the pros.

Answer 4

Having DIY'd a granite tile (24"x24") benchtop with undermount sink I'd say it's not that hard if you're careful and patient. As the comments above say you absolutely must use an alignment jig or similar. I had the freedom to use a drill press and I put masking tape on the stone to give a safe surface to get the last 1mm of alignment.

You probably need to press quite hard to cut the stone, the main cause of overheating is rotational speed You must use the lowest drill speed the drill will allow. With a drill press this would be less than 250RPM, handhelds rarely go this low.

For a hole around 2" it can be convenient to get one of the hole saws with a center bit and predrill an alignment hole with a 1/4" bit. The holesaw will try to wander when you first press it against the surface. Counter-intuitively applying more pressure (lots more) rather than less for the first 1/16 will get you a cleaner start with a handheld drill. Otherwise it can push with considerable force. If using a jig you must clamp it down firmly.

If you can't clamp the jig in place I think you should get the same effect by gluing it to the benchtop. Use a water soluble glue and test it by trying to knock it loose with a mallet. I haven't tried this but in principle it should be equally effective.