How to cut a perfect circle [In wood, plastic, & metal]

Introduction

The best way to cut a circle in wood, metal, and plastic depends on the size of the hole you want to cut out.

The best way to cut small circles up to 5 inches, is to use a power drill with a hole saw kit, while cheap you can easily cut out a perfect circle shape quickly.

For cutting circles bigger than 5 inches you want to use a hand jigsaw or better a powered jigsaw.

An electric or cordless jigsaw is designed to cut circles and curves easily, given that you mark out the line or curve you want to cut, and you guide the tool to the line you have marked.

There are a few other ways to cut circles using power tools like a band-saw, or you could even use a wood router if you have one around.

Cut a circle using a drill

If the hole you are cutting in wood is smaller than 5 inches you can use a power drill with the right sized drill bits.

You can use either spade drill bits or a hole saw kit for bigger holes.

Using spade bits

Spade bits are cheap drill bits made to quickly drill holes through timber mainly to run wires or do quick checkouts in framing timber.

For circles smaller than 1 and a half Inches, you can use a drill bit like a spade paddle bit.

The bad thing about spade drill bits is that they leave a relativity messy cuts. And the spade bits, can blow out and split the wood when it comes out the other side.

To avoid this first use a standard drill bit to drill a hole as a guide, then 2nd drill through both sides of the timber with a spade bit meeting in the middle to avoid this blow-out.

Pros:

• Cheap
• Fast with only the need to mark the center

Cons:

• Can blow out the back and leave a messy finish compared to a hole saw or standard drill bit.
• Maximum hole size is 1.5- Inches
• Can only be used for drilling holes in timber

Cut a circle using a drill and a hole saw

A hole saw can easily cut circles in wood and plastic, and if designed for its metal.

A hole saw kit can cut a circle up to 5 inches quickly and accurately. You will only need to mark the center to start your hole and have your 18 volt drill ready to go.

Some hole saws can only cut wood. But most can cut all materials including metals like steel.

If you need, hole saw drill bits for stainless steel  make sure your kit can handle it before you blunt your current drill bits.

Pros:

• Perfect Circle, and tidy cut
• Quick with only the need to mark the center of the circle
• Can cut metal, and plastic, as well as wood, depending on the hole, saw kit
• Reasonably cheap kit to get if you have a power drill already

Cons:

• It can only cut small to medium-sized holes depending on the biggest hole saw in a kit.

Click here for my review on the best hole saws and drillbits.

How to cut a circle in wood by hand

If you want to stick to hand tools to cut out a circle in wood,  and you need to cut out a hole bigger than what a hole-saw can do then you could opt for a coping saw.

A coping hand tool is relativity cheap to buy, but is only good for cutting the thinnest of wood materials, and is still a slow method of cutting curves and circles.

Coping saws are best for fine touch up’s in woodworking rather than cutting big circles out of wood, It would, however, be much more practical and faster to use an electric jigsaw.

Pros:

• Good for tiding up small woodworking corners
• Good for woodworking when it comes to dovetails and finger joins

Cons:

• Slow to use for any decent-sized cut
• The blade tends to bend and not cut straight with materials that are too thick 
• It can be hard to keep the blade square with the wood surface, as there is no base plate like what an electric jigsaw has.

The best tool to cut a circle is a jigsaw

An electric jigsaw is the best way to cut out a circle in wood, plastic, and thin bits of metal using the right blade attachment.

A jigsaw is a portable tool guided, free-hand to cut whatever shape or curve you want relatively quickly.

A jigsaw tool can be both corded and cordless. A cordless tool can be easier to operate, but can also cost a little more to buy.

The best corded jigsaw is a good choice if you want the cheapest tool for the job, with a little extra power.

However, a cordless model still has sufficient power for almost all jobs with added versatility and portability. A Makita or Dewalt 20v jigsaw is a great cordless choice for cutting circles in wood, metal, tiles, and plastic.

Pros:

• Fast as it is power-driven
• It can cut any size shape, curve, circle, or straight line.
• Changeable blades for different materials or types of metal and wood.
• You could use a timber guide to cut a circle more quickly and accurately if you don’t want to go freehand

Cons:

• It is required for you to fully mark out the shape and edge of your cut out.
• The cut might be a little jagged compared to a perfect hole-saw cut out, therefore, you might need to touch up your cut with some sandpaper at the end

How to cut a circle in wood with a router

If you don’t have other tools like a jigsaw on hand it is possible to use your best plunge router to cut out a circle in wood.

Depending on the thickness of wood you are cutting you would need to do the cut in multiple rounds, to avoid the router from being over-worked.

It is a bit of complicated set-up to just cut a simple circle. But as the video from YouTube below shows, you could even use this technique to cut circle patterns as well as a full cut.

You could just make the jig out of a piece of wood with a screw in the middle.

Although it would be much easier to just use a jigsaw tool.

Pros:

• Good For woodworking, less sanding needs to be done compared to a jigsaw

Cons:

• Not that time-efficient, as it takes a while to set up and cut
• Requires a big working space
• Unless you already have a router, I wouldn’t get one to only cut a circle

Cut a circle with a band saw

A band-saw is another way to cut circles in wood if the material is small enough to be lifted on to the band-saws table.

Band-saws are not the cheapest or easiest way to cut circles in wood however they are a good way to cut thicker gauged metal projects if you know someone that will let you use theirs.

Band-saws have more grunt and less blade flexibility than a jigsaw, making them more ideal for more heavy cutting jobs.

But they are not cheap or portable like an electric jigsaw tool, making band-saws only suited for commercial workshops.

How to mark-out the circle to cut

After you have picked a circle cutting tool for your job you want to mark-out the cut-out. The best way to mark out a circle is to first mark the center.

Next, you want to tie a piece of string to the tip of your pencil and cut the string to the length that you want the radius to be.

You can then attach the string to a screw in the middle and you can now use the string to guide your pencil to perfectly mark your circle on your wood, plastic, or metal surface.