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The hole for a faucet in my granite countertop is 1 1/4 inch. This limits my selection for faucets. I'm wondering if I can make the hole bigger without spending an arm and a leg.

I have lots of woodworking tools, and I could make a template with a hole the correct size, and use something like strong double-stick tape to hold it in place. I'm imagining something functionally like a diamond router bit like you'd do edge routing. But i don't know if anything like this exists, or whether it would even work. I suppose I'd need to take off at least 1/8".

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    Don't even think about it. You're going to wreck your counter. Dec 17, 2020 at 6:59
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    I understand silica dust is a problem for people who work in the industry. I don't know how much would be released, but if you attempt, I recommend planning for dust handling. Dec 17, 2020 at 22:49

7 Answers 7

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Two things:

  1. Do not do this yourself. The other answer is technically right but I would only do that if there was no hole. Either call up the place you got the granite from or another installer (which may run you $30-75). The issue is that once you start drilling and your bit catches the edge of the hole already there it will skip. Once it skip you can get chips or cracking. One of the harder tradesman things I can think of is making a hole slightly bigger. If you are going to do it yourself then sand it out with a dremel (which might take a while, yet won't damage.

  2. Make it 1.5" so that you future-proof this. I don't understand unless if it was a bathroom vanity why it wouldn't be 1.5" but that has been the standard for 15+ years for all kitchen sinks. I know guys that do 2". I wouldn't go 2" as that will require a cap (for the capless faucets) but 1.5" is safe and will allow you to buy 98% of the faucets out there.

Note: I really despise the "have someone else do it answers". But there are three things here - first just to do it yourself it will quite possibly be more expensive. Second you may never use this diamond bit again. Third you are talking about messing something up that is 1/30th of the cost to drill the hole bigger. The risk vs reward doing it yourself doesn't make sense.

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    +1 BUT - It's so important for us to know when "call in a pro" is the right answer. Whether for safety or risk of damage. Or, as you note, the actual tool needed for this one issue would likely never be used again. Dec 17, 2020 at 21:29
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    Rather than sanding it out with a dremel, I'd use a mini drum sander or cylindrical grinder on a drill - lower RPM but a dremel will stall too easily. They do go down to around 1" diameter. I'd still protect the surface very well. This is only worth doing for very small changes - if the hole and the tap nominally match but it just won't go through
    – Chris H
    Dec 18, 2020 at 12:07
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    That's a good answer on its own, but it would be useful to describe how a pro would do this job. If the right tools cost $200 while the repair costs $100, it could still be more satisfying to get the tool and do it yourself. I.e. I'm still salty from calling in a locksmith for a lost mailbox key for $120 after learning I could've bought a great set of lockpicks for the same price. Dec 18, 2020 at 18:06
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    @MartyFried there are guys who do nothing but drill holes in countertops for a living. There are contractors that will come out to deal with a situation like this. Dec 19, 2020 at 6:00
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    @MartyFried - if you have pros doing little stuff you are usually OK if you give them up to 10-15 days without a "timetable". If you need to schedule them they will charge you $100 usually, at the minimum 50-60. Cash helps, trusting you helps so good to have relationships and for some reason a case of beer is worth way more than the $25 you paid for it.
    – DMoore
    Dec 20, 2020 at 6:15
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Get a 1-3/8" diamond hole saw.

Create your 1-3/8" template secure it to the counter (make sure it won't move). I'd use something at least 1.5" thick so that the hole saw stays plumb. The template will serve in place of a pilot bit.

The Rigid 1-3/8" diamond hole saw from Home Depot is $28.

Buy a concrete paver while you are at it so you can get a little practice before you go all in on your countertop.

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    Ooohhh. Great idea practicing on a cheap-o paver instead of making the first whack directly on the expensive counter top.
    – FreeMan
    Dec 17, 2020 at 16:51
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    He will need two things to practice - scrap granite and a 1.25" diamond saw. First the concrete paver will break at the seam like 90% of the time. Second cutting a hole isn't hard and even if you kind of mess up there is a cap to hide it. Cutting a hole on a hole is the hard part and a chip or crack can go much further than a cap would hide. Unless this guy will be cutting holes the next few years he is much better getting someone that has practice and the right tools to take care of it.
    – DMoore
    Dec 17, 2020 at 18:15
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    Yep. Weigh the cost of hiring someone with the right tools and expertise, against the cost of replacing the entire countertop because of an avoidable error...
    – JRaef
    Dec 17, 2020 at 19:55
  • Do you have any thoughts on cooling while cutting? Water might help keep the dust down too. Is it necessary to seal the edge of the hole?
    – Criggie
    Dec 18, 2020 at 5:49
  • I've done cutting on manmade quartz but never using water. I typically keep a shop vac fixed near to the cutting area to suck up the dust. I use a cyclone attachment and a dustpal bag over the hepa filter in my shopvac. Dec 18, 2020 at 18:33
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Overall, the answer suggesting you get a professional to do it is the route to go. Make it someone else's problem and make sure to hold them accountable if they damage the counter.

Realistically though, if you get someone to show up at your home and pay them $30-75 like https://diy.stackexchange.com/a/211482/42053 suggests then accountability will be non-existent. At $30-75 you're just asking them to roll the dice because you don't have the equipment to do so. If this is a screwup then get the manufacturer to fix it because I sure as sin know that I wouldn't risk being held responsible for a couple grand countertop for $30-75 bucks. If they screw up then they'll just suggest a vanity cap and call it a day.


However, this forum post shares precisely your problem: https://www.ridgidforum.com/forum/mechanical-trades/professional-plumbing-discussion/42023-need-to-enlarge-a-granite-top-hole

Option 1:

Home depot now sells bits by ridgid that are an inexpensive diamond grit core bit.

The other way is to get a 1/8'' - 1/4'' carbide burr in a high speed dremel/ die grinder and route it out slowly.

I always use water/ wet sponge to keep the dust down and keep things cool.

Option 2:

I have the rotozip Floor Tile Bit XB-FTC1 1/4" diamond surfaced bit that I use in my rotozip for things like this and for some tile cutting and shaping. works awesome and is quite easy to control and handle.

Option 3:

I've never done this in granite so I can't tell you if it will work. It can be done in Corian.

Make a template in the diameter you want the hole to be in a piece of plywood. Make it big enough to provide a flat surface for your router to ride on. Clamp or otherwise secure the template where you want the hole to be located, maybe some double stick tape will work.

Use your router and a carbide pattern bit to enlarge the hole following the pattern with the router and bit.

If you go with the RIDGID diamond bit in your drill, you can still use the template secured to the countertop with double stick tape. Make the hole in the template the same size as the OD of the bit. Secure the template at the new hole location.

Now you can use the drill with less worry about the bit wandering.

Option 4:

I pick up the phone and call the nearest Granite fab shop. I don't do granite and I'm dang sure not paying to replace that high dollar slab when I mess it up.

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  • Thanks, a lot of good information. The granite isn't actually that expensive. I bought it about 10 - 15 years ago, and had a Chinese contractor we knew cut out the sink and holes. He's no longer doing this type of work, though. I thought it would be hard to get anyone to come out just to enlarge the hole; often, they don't want to waste the time. I do have some diamond bits for my Dremel tool, but I think they're too small. I'll probably just get a different faucet that doesn't need a big hole. Dec 19, 2020 at 5:51
  • @MartyFried Materials almost never make up the majority of the cost. Labor will always be 2x material as a starting price.
    – MonkeyZeus
    Dec 21, 2020 at 16:05
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    @MartyFried We don’t need to know that the contractor was Chinese. It feels like you are implying something negative or stereotypical about a person based on ethnicity.
    – Kris
    Dec 29, 2020 at 13:59
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    @Kris: Sorry, you're right, but I didn't mean it that way. I was thinking about the fact that they often don't know English very well, and therefore work cheap. I wasn't saying anything negative about his skills, but just that it was inexpensive. My wife is Chinese, so she knew him and could easily talk to him. Dec 31, 2020 at 21:53
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You might able to use 2 hole saw bits. One that fit snugly inside the existing hole and a larger one for the hole size you need. Nest the smaller one inside the larger one on one mandrel. The smaller one will keep you centered and the larger one will drill its size.

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This one's $500, but it's how it's done. I don't remember mine being so expensive; shop around. On the far left is the core bit you don't need. Second and third are the core polishers that you do: "Dia-Plus Resin Drum Wheel: Wet" except both of those in that kit are 2 inch.

You'll (really) want a badass grinder like that (variable speed and has a 12 AMP motor), and a drum wheel that will fit in your hole. My kit came with smaller drums; everything you'd need (not pictured; might be from Bosh, IDK...).

Sink Cutting and Polishing Package

enter image description here

diamondtoolstore.com

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    +1 badass grinder (i miss that girl)
    – Alaska Man
    Dec 20, 2020 at 1:59
  • I love the grinder and wheels. This is what the pros will use, doubt a homeowner spends this much to do it the exact right way but +1 to show people how its done right and fast. Cutting out a hole on top of a similar sized hole is hardly ever a good idea especially on something slippery as granite (I do my own bath sink holes all the time and wouldn't think about making them bigger drilling)
    – DMoore
    Dec 20, 2020 at 6:26
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I saw a technique for enlarging holes in wood that might translate.

The trick was to nest two hole saws on the same arbor. The inner (smaller) saw acts as a guide to keep the larger (outer) saw centered. Alternatively, a suitably sized plug of polyurethane or similar, on the arbor could have the same effect- keeping the surrounding saw centered in the existing hole.

This may not be feasible with diamond grit hole saws, but I thought it was clever and might be worth considering.

Good luck!

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If its new , i would consider sending it back.However if you want to proceed there are some options you need to consider.

I want you understand since the hole has been drilled already it complicates things alot, a hole saw needs a material to grab on (pilot bit), in order to prevent it from skidding around in a manner akin to writing with your non dominant hand.

Your Options:

  1. Send it off to be cut with a water jet(best option).
  2. use a router with a diamond bit and try to eyeball it going by hand (draw circumference on existing hole).
  3. use a step drill bit with lots of water(sacrificial).Surface thickness must not exceed distance between step or must not have a final size greater than 1 1/4" (last size of step in bit).
  4. Use a nested holesaw (TCT bit) , some holesaws allow you to put in two holesaws on a single arbor, a smaller and bigger bit , so you use the smaller holesaw as a guide for the bigger one.You need to drill from top and bottom surface about like 10% or your going chip the surface when the bit breaks through the surface!.
  5. turn a wood block of 1 1/4" on a lathe and plug the hole and use a diamond core bit with a drill , same thing about drilling both sides applies with lube mentioned in option 4.

Note: with all methods you need to apply lubricant/water when cutting to keep the dust down and/or wear a p2/n95 mask(full/half respirator). Silicosis is no joke , you don't want to be out of breath due to lung problems later in life...trust me it's bad.

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