Cutting granite worktop for new sink - size issue?

[HBoy]

Hi

This is my (now very old and scruffy) kitchen sink underslung a granite worktop. The depth (or is it width?) of the granite - shown by the tape measure - is 620mm.

I have purchased a new sink for inset fitting that is 1000 x 500mm and my plan is to cut the granite for it to fit, both increasing the depth and width. I am an experienced DIY'er and I think I can take that on using angle grinder and diamond disc and a lot of patience. The issue I have is the minimum granite depth stated for the new sink is 800mm, which would give (800 - 500)/2 = 150mm front and back edge of the sink. In my situation, I will be left with 70mm front and back edges (allowing for the lip).

Is this going to cause a problem, i.e break because it is too thin?
I presume reinforcing underneath these long thin stretches of granite help?
Is cutting granite as described achievable for DIY'er?

Thanks!
H-Boy

 

[foxhole]

Should have asked the question before purchase.

 

[phatboy]

The only plus here is you will make such a mess of that worktop with your grinder, that your house insurance should pay to replace it.

However you cut it, it will look terrible. These things are cut with specialist tools in a factory for good reason!

 

[johnny2007]

As others said: do not do it.
Granite is a very hard stone and you'll never be able to cut it in place properly.
Front and back of the sink should already have a metal bar reinforcement from factory.
Look underneath.
Again, do not do it, keep what you have.

 

[Robotmannick]

Not what you want to hear but it's another vote for "this'll never work”. The sink and worktop look fine, it's the tiles that I'd be looking at changing.

Sorry.

 

[lostinthelight]

I seriously doubt you would ever cut internal radii in granite let alone polish to a surface that didn't looked anything other than dull and grubby, not really the look your after I suspect if the reason for change is a grubby bowl?
Why not save yourself some grief and refinish the old one.

 

[freddiemercurystwin]

Doesn't the OP's sink sit on top of the worktop? In which case why does the cut out need internal radii? Or need to be polished? In anycase I'd get a granite expert in to do it insitu though they may have the proviso if something goes wrong it's not their fault.

 

[phatboy]

Doesn't the OP's sink sit on top of the worktop? In which case why does the cut out need internal radii? Or need to be polished? In anycase I'd get a granite expert in to do it site though they may have the proviso if something goes wrong it's not their fault.

Did you see the photo?!

 

[freddiemercurystwin]

Did you see the photo?!

Ooh, what have I missed? Something obvious?

 

[lostinthelight]

Doesn't the OP's sink sit on top of the worktop? In which case why does the cut out need internal radii? Or need to be polished? In anycase I'd get a granite expert in to do it insitu though they may have the proviso if something goes wrong it's not their fault.

I think your right, its an inset not undermount looking a the link for the replacement.
If it is indeed an inset type then it's quite doable. My 1000 x 500 inset has a rear border of 50mm and front of 600 but is well supported. Its a good idea to keep vibration to a minimum while cutting and cut into pre bored corners

 

[freddiemercurystwin]

He said it's an inset sink in his first post and here is a link to the sink: https://www.blanco.com/gb-en/download/specsheet/59.816/

 

[HBoy]

Thank you for the replies, which seem to be leaning towards 'don't do it'. That's right FreddieM, the existing sink is undermount and the new replacement sink is inset, so I was assuming that anything I cut will be covered by the new sink with no need for polishing etc. I was planning to clamp an mdf template (which I'd have to make as the new sink doesn't come with one) to form the cutting area and prevent the grinder drifting. I realise after reading lostinthelight's second comment that I could opt for a narrower edge at the rear, supported by a timber strip attached to the wall. Oh, God, it's really tempting just to have a go....

 

[freddiemercurystwin]

Thank you for the replies, which seem to be leaning towards 'don't do it'.

I think that's really based on the assumption that you were fitting an undermount though. You could try a test cut where the existing drainer is though obviously that's the point of no return at that moment! Perhaps line a 'proffesional' up beforehand? Might not cost as much as you think anyway.

 

[johnny2007]

You'll need a 9 inch grinder and a marcrist diamond blade and it is not even guaranteed that it won't crack.

 

[IT Minion]

FWIW when I had to get a granite counter cut down to size my local granite supplier was happy to do it for £20. I'd guess a sink would be more, but definitely worth asking. Sometimes the best DIY you do is getting someone else to do it.