The size of a cooktop cutout in a granite counter is increased by cutting along the new perimeter, marked using a template, with a circular saw. The freshly cut edges are smoothed out using a power sander and the inside corners are rounded with a power router, explains eHow.
The new, larger perimeter on the granite counter is marked using the template of the new cutout. For this, the template is placed on the existing cutout so that the edges overlap. The edges are then lifted and masking tape strips placed on that area. The perimeter of the template is then traced over the masking tape using a marker and the template is removed.
With a circular saw, the market perimeter is cut. A 4-inch angle grinder is used for the same purpose in areas where there is inadequate space to use a circular saw. Before cutting, a vacuum is attached to the hose of the circular saw so that the dust generated while cutting is quickly drawn away.
After cutting along the entire perimeter, the edges are smoothed out with a power sander, to which a 100-grit sandpaper is attached. The inside corners are curved by two degrees with a power router so that heat does not crack the counter, according to Do It Yourself. Finally, the masking tape is removed and the counter wiped to clean away remaining dust.