Best Bit or Saw for Granite Countertops

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
I need to enlarge a hole in a sink countertop from 3/4 to 1 1/4. What have any of you used to do this? I'm pretty sure a unibit wouldn't do it at all. I've seen a few carbide holesaws on store shelves but never used one. I wouldn't chance trying a rotary hammer bit on it, I'm sure it would crack or crumble. I saw a no bit holesaw on Youtube with a guide to hold it. Something like that may work.
 
Just got to a tile store. Any diamond embedded hole saw designed for tile will easily cut through granite. As noted you don't want to use a hammer drill.
 
If trying to enlarge in the same center, a trick is to use the smaller hole saw in place of the pilot and the larger outside. Here is a device sold by Rack-a-tiers to do that easier: https://rack-a-tiers.com/product/the-co-pilot-hole-saw-adaptor/
In stone tile or masonry I would be using the diamond saw and low speed, can add a little water to help keep it cool. Heat is your enemy on the diamond bits.
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If trying to enlarge in the same center, a trick is to use the smaller hole saw in place of the pilot and the larger outside. Here is a device sold by Rack-a-tiers to do that easier: https://rack-a-tiers.com/product/the-co-pilot-hole-saw-adaptor/
In stone tile or masonry I would be using the diamond saw and low speed, can add a little water to help keep it cool. Heat is your enemy on the diamond bits.
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That’s nice. I’ve always used a longer pilot bit and clamped a piece of wood to the slab, tile, etc.
 
Add a lot of water to wash away the dust and keep it out of the air, you really don't want to breath the stuff.
I was going to say that as well; silica dust from cutting stone is a very potent carcinogen if inhaled.
 
Diamond hole saw. (y) Keep it flooded with water, use slow speed.

If you don't have one of those fancy hole saw jigs, get a piece of 3/4" plywood, cut a hole the size of the new hole in it, in this case 1 1/4", and set it, clamp it if you can, centered over the original hole, and put your diamond bit inside that, and it will hold it centered.
 
Boss told me to try a standard 1 1/4 hole saw. It worked & better than I thought. Turns out, the countertop is some kind of composite, probably plastic & something. We wet the hole & wet the saw several times, cut slowly.
 
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