Replacing a worktop in a kitchen or bathroom requires reinstalling a sink. New sinks are sold with templates that outline the cuts necessary, but reusing existing sinks requires careful cutting. The method of cutting depends on the worktop, but most wood or laminate tops are simple to cut using a jigsaw and a drill. Installing an under-mount sink requires using the manufacturer's supplied template. Top-mount sinks allow for the sink itself to be used to create a template.
Set the worktop right-side up on a flat surface. Position the sink upside down on the worktop so that the lip of the sink is resting on the top of the worktop. Position the sink precisely where you want it installed. Trace the outline of the sink onto the worktop with a pencil to create a template on the worktop.
Measure the flat lip that goes around the sink and connects to the sink basin. Most lips are approximately 1.25 cm (1/2 inch).
Measure and mark inside the template created in Step 1 using the measurement determined when measuring the lip. Place marks around the entire template and connect each mark using a straight edge. The end result will create a centre template similar to the outer template, but smaller in size.
Drill a 1.25 cm (1/2-inch) hole into the worktop along the edge of the inner template so that the outer edge of the hole created is flush with the line for the inner template.
Cut the hole for the sink with a jigsaw starting at the drilled hole and tracing the outline of the inner template. Dry fit the sink by setting it into the hole properly to verify that the lip rests firmly on the worktop. Mark any points that need attention and cut those points properly with the jigsaw.
Applying painter's tape around the template flush with the lines of the template will help prevent laminated surfaces from chipping. Cutting stone, cement, or tile worktops require the use of specialised saws and saw blades, and should be left to the professionals.