How to Open up Kitchen Counter for Cooktop?

[Chips O'Toole]

This is not really a woodworking question, but it's closer to woodworking than machining.

I have a new 36" cooktop. I have granite counters. The cutout for my old cooktop is about 1/8" too narrow for the new cooktop.

What's the best way to open it up? I need about 1/6" on each end.

 

[RJSakowski]

The usual way for quartz or granite surfaces would be a diamond saw. I don't know if the DIY grade of blades will do the job. You may need an industrial rated blade.

 

[Flyinfool]

First question can the countertop be removed? If so then you could take it somewhere that has the proper equipment to cut it.
It would be best to cut with a diamond blade that is water cooled, Would make a monster mess in the kitchen.
Since it just one or 2 cuts a DIY blade run dry MAY get the job done.
The other option is to apply masking tape to mark the line and use a dimond disc in an angle grinder and just grind up to the line

 

[Chips O'Toole]

There is no way it can leave the kitchen. Maybe an angle grinder will be the best answer.

 

[aliva]

An angle grinder with a diamond blade is what my installer used to adjust my counter top. Just use a second person to apply a slow water drip to the surface to keep the blade cool and the dust down. Be prepared for a little mess, wear a mask

 

[rwm]

I have done this several times with an angle grinder and one of those "serrated" diamond blades. They will cut it just fine. I did it dry. The issue you will run into is that for standard 1-1/4" thickness granite the blade will not be able to cut all the way through. The gearbox will hit. If you can cut from the top and bottom and you don't care what the cut looks like you will be fine. I used a 7" angle grinder for a long cut that had to be cosmetically good and that easily clears. Also cutting of 1/8" may be tricky. Can you cut off 1/4"? That might be easier.


Robert

 

[Superburban]

for 1/8", I would consider a diamond grinding blade for the angle grinder. Water I think is a must. Or have several blades on hand. I would use plenty of plastic to cover as much as you can. A square bucket, bread pan, or similar underneath to catch as much water as you can. Also watch for water hurting the grinder. Use tape or something as a guide to grind up to.

 

[rwm]

The blade above will work fine DRY. Just don't push it too hard. It will make a lot of dust!
And on second thought- you won't run into a clearance issue with this particular cut since you can put the gearbox into the existing cutout. You can see how this would be an issue if you were making a cutout from scratch.
Robert

 

[Chips O'Toole]

Thanks for the help. I got a diamond wheel and let fly. Dust went everywhere, but it did the job.

Now I have to find a way to connect 1" flex conduit to a handy box with 1/2" knockouts. For some reason, the flex conduit on the new cooktop is bigger.

 

[benmychree]

Possibly you can use an electrical knock out punch to enlarge the existing hole, or go to a larger square junction box with 1" holes.