Diy virgin needs help - How do i cut a half circle into a slab

[gav_j_crompton]

Hello everyone,
I am new to the diy'ing and this discussion forum so I apologise if I ask a stupid question. I have a rough idea how to cut a semi-circle into a slab and I guess it envolves a disc grinder, but I don't know how to smooth of the edges and how to make sure I get a true circle. Kind of need the answer soon as I have a patio to finish and show off to the in-laws,

Ta any help offered much appreciated

[Tony McC]

What size is the circle? It's almost impossible to cut anything smaller than 750mm diamater with any real degree of accuracy using a cut-off saw or nangle grinder.

[telvis]

try laying 5 or 6 slabs on top of each other, the slab u want to cut on top of them, over hang the part u want to cut out, weighted down with 3 or more slabs to hold it in place securely, u will then find u can cut into the slab with an angle grinder up the outline of your circle, making cuts every half inch or so, when done, simply tap out the cut bits of slab with a hammer and if you're good u can smooth the rough edges with the angle grinder, if not, pointing hides a multitude of sins:)