I have a granite kitchen countertop with a 3/4" hole that was used for a filtered water spigot. I am replacing the filtered water with a Hot Water Dispenser.

How do I increase the 3/4" hole to between 1 1/4" to 1 1/2"?

Carefully..


But really you might fill the hole with a piece of wood(2X4)(you'll need to make it tight)
The wood would act as a solid to allow the hole saw a center point.
Then a professional grade hole saw(most plumbing supply stores/hardware)will have these
Cutting will take time,but with effort and patience you'll get it.

Hope this helps,
Ken

KBC has the correct approach, probably use a 3/4 " dowel rod soaked in hot water. Pros cut these holes with a wet saw and a dam around the hole made from child's clay. Add 1/8" water and once you start cutting a slurry will form that helps in the cutting.

I have a granite kitchen countertop with a 3/4" hole that was used for a filtered water spigot. I am replacing the filtered water with a Hot Water Dispenser.

How do I increase the 3/4" hole to between 1 1/4" to 1 1/2"?
Sorry I have left this question open for so long... I had someone who claimed they could make this cut for me but it obviously never happened and then the holidays approached. I didn't want to chance a problem counter top during this time.

If I got this right I should soak s 3/4" dowel rod in hot water to plug the existing hole. I then should create a dam around the hole using clay and then adding about an 1/8" of water.

My question is what kind of wet saw/drill should I attempt to rent for this cut?

http://www.tiletool.net/wpe8.jpg

Diamond hole saws (http://www.tiletool.net/hole_saw_diamond.asp) work well with a power drill.

Thanks,
Json

Schwim's pics are perfect. You can rent these at Home Depot and other rental centers rather than buying for a onetime shot. You understood the dowel rod and clay dam correctly. The 1'8" of water keeps down the dust and cools the diamond saw.

That did it!!

Using a dowel rod soaked in hot water with a clay water dam did the trick. The hole cut easily using the above listed 1 1/8" diamond hole saw I purchased from tiletool.net. The new hot water dispenser is installed and functioning.

Thank You.

And thanks to Schwim for his pics too. Harleysdream doesn't need to worry about breaking his granite, it may spald on the bottom side it will not break. Glad everything worked our for you.
Bob