What type of corbels are needed to support a granite counter top

Cutting the countertop to length:

Try making a custom circular saw jig to cut your countertop to size. 3/4" plywood placed together at right angles with a cleat for guiding your saw should give you a straight cut. Assemble the jig with extra material, then cut it to size with your saw for a perfect fit.

Use a saw blade with a high tooth count and cut the counter upside down. That way, the blade teeth are traveling down (but really up) into the counter surface, minimizing chances for chipping out. Start by cutting the backsplash first, with the rest of the counter pointing towards the floor. Then stop and rotate the countertop so it's upside down and finish the cut. Be sure to support the cutoff material so it doesn't break off a chunk of the laminate near the end of the cut.

As @auujay points out, masking tape can also help reduce the likelihood of chipping.

Source: woodworkingtips.com

Cutting the sink hole:

I crawled several forums looking for advice on this one. Some suggested techniques (in the order that I would try them) were:

• Use a jigsaw with a down-stroke blade to cut out the sink hole. By cutting on the top surface, you have a more accurate picture where your sink hole will be, and the downstroke blade will eliminate chip-out. Start each rounded corner with a 1/2" spade bit.
• Use a jigsaw with a metal cutting upstroke blade. The finer teeth will make for slower work, but have less of a chance of chipping.
• Use a circular saw to cut straight sides from underneath the countertop. Flip over and finish the rounded corners with a downstroke jigsaw blade.

Once again, use masking tape for both cut line visibility and to reduce the chance of chipping the laminate. Also remember to support the cutout section to avoid tearing the laminate near the end of the cut.

You can use this type of bit. First drill a pilot hole of 3/5mm before using this.

Found over here

or this - but its more difficult - It says for wood but you can use them for soft steel as well but you need to constantly lubricate (lots!! dont be shy) the bit/surface to keep it cool using WD40 lubrication oil and drill at a slow speed. This is more dirtier and the edge can be rubbish.

Then you can mount something like this

These can be found at furniture shops/ swimming pool shops/ hardware stores.. you will need to find the one you need and possibly DIY it slightly.