How to Make a Radius Corner on Countertop
You could use a jig saw, belt sander and speed square, but if you make a template of the size radius that you need to put on the countertop, the edge cut will be square. Here’s how we have made round corners on our Formica or plastic laminate tops for many years. This method will apply to just about any type of material that can be shaped (or, “cut”) using a router. By making a template to follow your final product will be perfect.
Steps for making a radius (or, “round) corner on a counter edge
1) Make a jig or guide for the router to follow on a board that is about seventeen inches square. Most standard kitchen radiuses are 2”-3” on the end of base cabinet overhangs and bar counter tops should have 6” round corners wherever possible. Using a saber saw cut just barely oversize and use a belt sander or hand block sander get the templates edge to be as close to perfect as possible.
2) Once the counter is fabricated to the desired size use the template and draw the radius onto the top using a pencil.
3) Precut the shape about one eight of an inch larger than the pattern line that you drew.
4) Using c-clamps or Jorgensen clamps, secure the template into position leaving enough room for the router to be able to make a complete pass and cut the radius on the Formica, wood, or solid surface countertop.
5) Using a ½” shank router bit 3” long, adjust it so that the flat part of the bit (or, “shaft) can follow the template and the cutter blades will cut the top. Your bit must be sharp.
6) Position yourself so that you can hold the router firmly to the work surface and also hold the counter from moving. You may need to clamp the top or have someone hold it for you while you route it.
7) Rout the radius edge on the countertop.
This is how to get an almost perfectly square edge on the counter when you are adding a radius corner onto a plastic laminate counter or solid surface countertop. It is possible to use just a saber saw, sander and square but it will never be as accurate as using a router to make your final radius cut. This method is a must if you will be gluing any type of edge to the top. In order for material to adhere to the round shape, the edge must be square. If it is not, the Formica or wood veneer will ride away from the top as you are applying it to the radius causing void areas to form. If this happens, the areas are likley to crack when pressure is applied to the void.