Replacing your old drop-in sink with a new stainless-steel sink is one way to update the look of your kitchen. When replacing the drop-in sink, purchase the correct size sink for the hole in your countertop. Measure the overall inside width of the current sink as well as the length. This will ensure that your sink fits your countertop. Remove any residual putty and grime from around the hole before installing the sink. A drop-in stainless-steel sink installation requires sink clips to secure the sink. Although sinks come with clips, it is a good idea to have extras if you need them.
Remove the faucet assembly from the old sink, and install it to the new sink. Most faucets secure to the sink with retaining nuts around the faucet handle stems below the sink. Remove and tighten the retaining nuts with a wrench. Wrap the ends of the faucet handle stems with plumber's tape, after installing the faucet to the sink.
Set the sink into the hole in the countertop to ensure the hole is square and that the sink fits. Pull the sink out of the hole and place the sink upside-down on the counter with the faucet hanging over the edge of the counter. Use a coping saw to cut the countertop hole as necessary for the sink.
Place masking tape around the perimeter of the sink hole, 1/8 inch away from the edge of the hole. This provides a guide for the sealant. Slide the sink clips into the channel on the bottom of the sink. The "T" portion of the clips slides into a channel on either side of the sink. Generally there should be two clips on each end of the sink with four to six clips along the front and back of the sink. Turn the curve edges of the clips toward the sink.
Apply a 1/4-inch bead of silicone caulk around the perimeter of the sink hole between the hole's edge and the edge of the masking tape with a caulking gun. Turn the stainless steel sink right-side up, and insert the sink into the countertop hole with the faucet toward the back of the counter. Press the sink down firmly so that the flanges contact the caulk.
Go under the sink and turn the curved portion of the sink clips to point away from the sink bowls. The curve edge will now be under the solid portion of the counter. Tighten the screws on the ends of the sink clips with a flathead screwdriver to secure the sink to the counter. The clips will close over the countertop as you tighten the screws. Tighten all the sink clips evenly.
Place a small ball of plumber's putty into the palm of your hand, and roll the putty between your palms to form a rope. Place the rope of putty under the flange of the new sink drain baskets. Insert the baskets into the recessed hole in the bottom of each sink bowl. Go back under the sink and slide the rubber washer over the bottom exposed threads of each sink basket. Secure each basket with the large retaining nut and tighten the nut with a pipe wrench.
Hook up the sink drain to the bottom of the drain baskets, and hook up your water supply lines to the sink faucet. Trim the excess caulk and putty from the edge of the sink and the drain baskets with a utility knife. Peel the masking tape off the counter.
If installing a sink into a new countertop without a hole, use the template included with the sink to cut the hole in the countertop according to the manufacturer's instructions.