Even though it seems like it should be a simple task, cutting a circle with a router is a lot trickier than most people think. There are a few different ways to get the job done, and the method that works best for one person may cause someone else nothing but frustration. If you’ve been struggling to create a good-looking circle with a router, don’t worry: With a few adjustments to your technique, you might find that cutting a circle with a router is easier than you ever imagined.
Estimating the Circle
The first thing that you need to do is make sure that you know just how big of a circle you need to cut. Determine a center point on your circle and mark it on your wood, then measure out the radius from that center point and make another mark to show where the circle wall will go. If you want to be thorough, make three additional marks at 90-degree increments so that you have marked both the x and y axis in the circle.
With these points marked, some woodworkers stop here. You don’t have to, though. If you wish to mark the complete circle, drive a nail into the center point or drill a hole that you can insert a pencil or dowel into. Attach a string or thread to this center post, making it loose enough that it can rotate around the post without wrapping or binding.
Tie the other end to a pencil so that the pencil tip is on one of your points when the string is taut; from there you can keep the string taut and draw a circle around the post. The string will keep the pencil at the same distance as you draw, so your circle should cross any points you made along the circle wall.
The most common way to cut a circle is to build a router jig that’s secured to a center point and moves the router in a circle. This is usually accomplished by drilling holes in a small block of wood and inserting dowels or rods into the hole, then inserting the rods through the holes in the base of your router. You can then drive a nail through the block and place it into the hole in your center point, sliding the router along the rods until its point lines up with one of your marks on the circle wall. Set the router depth and turn it on, slowly moving it in a circle around the center point with your jig.
If you want a more repeatable solution, you can build a custom jig, featuring a larger flat end that you can attach to your router base with screws. From this, there should be a longer, thinner extension with holes drilled every half-inch or inch; driving a nail through one of these holes into the wood underneath will give you a pivot point for your jig. You may also be able to find prefabricated jigs that work in the same general way that are made of plastic or other material.
If you’re not as concerned about accuracy and just need a small circle, you can also attempt freehand cuts with your router. For these, you should have the circle drawn completely on your wood and should practice on scrap wood to get the hang of following curves without a guide.
While you will get a more accurate end result with a jig, making freehand circle cuts can certainly save you some time and may still produce some good-looking circles provided that you’re willing to practice your freehand cuts first.
Turning the Router
One big point of contention among woodworkers is how to move the router around the circle. Some insist that only counterclockwise movement should be used, while others insist that a mix of clockwise and counterclockwise is better. This is largely a matter of personal preference, as either will give you good results so long as the direction is appropriate to the cut that you are making.
What’s your preferred method of cutting a circle with a router?