Cutting corners on granite worktop with angle grinder

[TD]

I'm halfway through widening the hob hole in our work top. Blue Bosch grinder, diamond blade, all good so far, even straight lines! This is the only tool I own that has made any impact on the granite whatsoever.

However I'm a bit stuck in the corners. Due to the natural round shape of the blade, once it starts to cut at the end of a side, it doesn't cut deep enough, so I'm left with pieces that will be 99% cut and held on at the corners...

How can I get around this? I'm thinking of cutting from underneath but it will be uncomfortable. Is there a better way?

[F Murtz]

May be too late now but you can get carbide or diamond hole saws if you have not cut too far to the corner

[John Rumm]

There is a better way - but it might be hard to use if you have already cut up to the corners.

The ideal way would be to start at the corners with an appropriate sized diamond core drill. Then to use the grinder to cut the sides between the holes.

You may still be able to use this approach if you make a ply guide with a core sized hole through it, that you can clamp to the surface and use as a way of holding the core bit in position.