NEWTON MAKES

View Original

7 Ways to Cut Circles

There’s always more than one way to do something.  This blog and the accompanying video shows seven different ways I use to cut out circles out of wood, drywall, plastic, or whatever else needs cutting!  I show step by step various ways to cut out a perfect circle using different tools.  Some circle cutting processes are pretty cheap, while others are a little more expensive.  All work though! 

Cutting a Circle with a Table Saw

You can safely cut a circle on the table saw.  It will require either a table saw sled or by using your saw’s miter gauge.  I used some tape to secure a sacrificial board to my table saw sled.   Then I pushed the board through the blade.  Mark a center point on the workpiece that you want to cut into a circle.  Approximately half way down your sacrificial board, mark a line that is half the size of your circle.  If you want a 12” diameter circle then mark your line at 6”.  Drill a small hole in both the sacrificial board and the workpiece that will serve as a pivot point.  I used a small dowel, but you can also use a cut off nail. 

Put your workpiece on the sacrificial board and make sure it spins smoothly.  Cut off each corner of your workpiece.  Then spin the board and cut off any of the newly created corners.  And then do it again.  The more corners you cut off, the safer it will be.  Once you get to the point where you don’t have any more corners to cut, move the workpiece so that it touches the front tooth of the blade and slowly spin your workpiece into the blade. 

Cutting a Circle with a Bandsaw

It’s easy to cut a circle with a bandsaw.  I placed a sacrificial board on my bandsaw so that the piece will be slightly cut by the blade when pushed through.  I marked on the board where the T slot is located.  Using some double-sided tape or glue, attach a board that fits snugly into the T slot.  I luckily found a piece of scrap in the shop.  Don’t worry about making your newly created jig square to the blade.  It really doesn’t matter because you’re cutting out a circle. 

Drill a center point in your workpiece and a pivot point in your sacrificial board, just like you’d do if using a table saw.  Push the workpiece into the blade.  Once the piece is about halfway through, slowly spin the board and you’ll cut out a perfect circle!  I recommend using a thin blade.  I used a 1/4” blade in the video above.  A wide blade may make it difficult to cut smaller size circles.  This is one of my favorite ways to make a circle.

Sanding a Circle

Another way to cut a perfect circle is actually sand it into shape.  I used a hand saw to cut away the corners of my workpiece.  The more I cut off, the less I have to sand.  You really don’t want to sand away most of the circle because it produces a lot of dust. Drill a center hole in the workpiece and a mating hole in a sacrificial board.  Again, a dowel or nail works perfect for this.  

I clamped my sacrificial board to the table of my disc sander.  This isn’t a fancy tool.  I got it at Harbor Freight, using a coupon so it was pretty darn cheap!  The front of the board is clamped, but the back isn’t.  Now, I can pivot the back of the board into the sander until the workpiece touches the sander.  Once it does, spin it until the circle is sanded evenly on each side.  This is one of the fastest ways to cut a circle.

Circles on the Router Table

Another way to cut circles is to use the router table.  I made a quick jig that will fit on my router table and allow me to work safely.  The jig is simply a board with a fence glued to it.  I cut a few holes in the board to form a channel for the router bit to stick through.  Like with the rest of the methods I described, you need a pivot point so drill a hole in the workpiece and into the jig. 

With the router off, place the jig onto the router table and raise the bit so that it fits through the slot that you drilled out.  Clamp the jig to the router table fence.  Place the workpiece onto the jig so that it spins freely, but does not touch the router bit.  Tighten the right corner of the fence, but not the left corner.  Turn the router on and move the left side of the fence away from you until the workpiece begins to touch the spinning bit.  Tighten down the left side of the fence.  Now, you simply have to spin the workpiece and let the router do the work.  Watch the above video to see this exact process in action.

Jigsaw Circle Cutting Jig

You can always free hand cut out a circle using a bandsaw or jigsaw, but we’re talking about cutting perfect circles, which means we need a jig.  I took three pieces of plywood to made a U shape that holds my jig saw.  You don’t want any play in this.  The jigsaw should fit into it snuggly.  I drilled a hole into both sides of the jigsaw holder and slid a 5/8” diameter dowel into it.  Next, I made a pivoting hub from scrap plywood.  I drilled a hole into the center hub so that the dowel also fits into it.  I also cut out a kerf in the jigsaw holder for the blade to stick through.  The only thing left is a way to lock everything into place.  I used some scrap plywood to make clamp blocks that can be tightened down onto the dowel with a bolt. 

Now, I can drill a center hole in my workpiece for the jig and have the center hub spin on a dowel.  Drill a hole just on the outside of the circle on your workpiece so the jigsaw blade sticks through it. Cut your circle by going slow; don’t push it hard. I recommend using a thin blade for this jig.  A thin blade will allow the saw to pivot easier.  This is also a jig to make larger size circles.  I wouldn’t recommend it for small pieces.

Router Circle Cutting Jig

I think my favorite way to cut out circles is to use a router circle cutting jig.  I have this jig by Milescraft and it works awesome.  It has a lot of adjustability so it can be used for small and large circles.  The router is screwed into one end of the jig, while the other end pivots on a screw that’s in the center of the workpiece.  Plunge the router down to a depth that’s about half the width of the router bit.  If you use a 1/2” diameter bit then you can plunge it down 1/4” deep.  This is a general rule of thumb so that you don’t attempt to take off too much with one pass.  Spin the router and cut a circle.  Lower the bit down further and do it again.  Keep doing it until you cut all the way through your workpiece. 

I have a specific video on this exact process, which you can check out there: Router Wooden Bowl

Cut Circles with a CNC

Okay, this is probably too easy to mention, but I did give you six amazing ways to cut out a circle using cheaper tools.  If you want true precision then opt for the CNC.  I like to make a circle or any other shape using Inkscape, a free vector software.  Load your vector file into whatever software your CNC uses.  It’s pretty simple and honestly, there are probably better sources for CNC tips and tricks because I don’t use a CNC that often.

*As an Amazon Associate I earn from qualifying purchases.