How to Cut Circles - 4 Methods

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Introduction: How to Cut Circles - 4 Methods

About: DIY Montreal is all about woodworking & DIY projects. I post how-to videos on my YouTube channel, as well as step-by-step tutorials on my website www.diymontreal.com. Builds include mainly woodshop project…

In this tutorial, I’ll show you 4 ways to cut circles in wood, using DIY homemade circle cutting jigs.

Below, I’ve included a summary of how to make each circle cutting jig, whether it be with a router, a bandsaw, a table saw, or even a jigsaw. For a closer look at each method, be sure to check out the YouTube video.

Supplies

Step 1: Router Circle Jig

The most common way of cutting circles in wood is using a plunge router with a circle cutting jig. Now, you can buy a circle jig to fit your router, like this one, or you can make one yourself out of 1/4 inch plywood. I used my bandsaw to shape it, but this step is optional.

Remove the base plate from your router and use it to trace the screw holes on one end of you strip of plywood.

Then attach the router to the plywood making sure to countersink the screw heads.

Plunge the bit through the plywood jig, then remove the jig from the router and make the hole bigger.

Step 2: Using the Router Jig

To use the jig, make a small pilot hole in the jig, measuring from the edge of your router’s bit. For an 18 inch diameter circle for example, make a pilot hole at 9 inches from the bit.

Find the center of your wood blank and drill a pilot hole, then mount the jig using a finish nail.

With an upspiral bit mounted in the router, plunge the router 1/8th of an inch and guide the router around in a clockwise direction until you’ve made on full revolution.

Adjust the bit to plunge 1/8th deeper and make another revolution at this depth. Continue until you make it all the way through the wood and you’re left with a perfect circle.

Step 3: Router Circle Jig + Jigsaw + Flush Trim Bit

This method starts out the same as the previous using a plunge router and a circle cutting jig. Using the upsiral bit to make 2-3 revolutions, then remove the circle jig and grab your jigsaw.

Using the jigsaw free-hand, cut out the circle using the groove as a guide. Avoid getting too close to the inside edge of the groove, so that when you’re done, you’ll be left with a lip all round the circle.

Grab your router and install a flush trim bit with a bearing. Plunge the router and line up the bearing with the clean lip previously left by the router.

Going in a counter-clockwise direction, progressively shave off the excess wood until the bearing contacts the lip. Go all the way around the circle until you are left with a perfect circle.

Step 4: Bandsaw Circle Jig

If you have a bandsaw, I highly recommend this method. Cut a runner out of hardwood to fit the bandsaw’s miter slot, and a piece of 3/4 inch plywood. Attach the runner underneath the plywood so that the plywood overhangs the bandsaw’s table on the right.

Mount the sled to the bandsaw and cut the kerf, stopping about half way through.

Then mount some stops from underneath up against the front edge of the table.

Trace a line perpendicular to the front tip of the kerf line, then drill a pilot hole on the line to match the radius of the circle you want to make. Use a finish nail with the head cut off as a pivot pin.

Step 5: Using the Bandsaw Circle Jig

To use the jig, find the center of your wood blank and make a small pilot hole, then mount the blank to the pivot pin on jig.

Using a 1/4 inch bandsaw blade, slide the sled forward straight, cutting into the blank, until the stops hit the table and you can’t push the jig forward any further.

At this point, simply rotate the blank clockwise and cut the circle.

Step 6: Table Saw Circle Jig

The last method made me a bit nervous at first, but I just had to give it a try. Cutting circles with a table saw? Yes, it is possible.

Mount a runner to a piece of 3/4 inch plywood, then run the sled through the blade to trim off the excess and create a zero clearance edge.

Trace a line across the sled, perpendicular to the blade, about half way front to back. On this line, drill a pilot then drill hole on the line to match the radius of the circle you want to make. Use a finish nail with the head cut off as a pivot pin.

Step 7: Using the Table Saw Circle Jig

To use the jig, find the center of your wood blank and make a small pilot hole, then mount the blank to the pivot pin on the jig.

Start by slide the jig back and forth through the blade to cut off the 4 corners of the square blank.

Continue to cut off the 8 remaining tips of the blank. Then again to cut off all remining protrusions until your blank is as close to a circle as you can make it.

Line up the line on your jig with the front tip of you saw blade, then use a magswitch or stop to lock the jig in the position.

Using push pads to protect your hands, rotate the blank clockwise into the blade in order to shave and sculpt it into a perfect circle.

Step 8: Choose Your Method!

My favorite method was definitely the bandsaw, while my least favorite was the Table saw.

The router option is messy, but there's no limit to how big you can make your circle, like for a tabletop. I prefer to stick with the upspiral bit all the way through.

If you haven't already, watch the YouTube video for more details, and if you like what you see, subscribe to my YouTube channel.

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    41 Comments

    0
    YzYnGy
    YzYnGy

    1 day ago on Introduction

    Thank you for this excellent presentation & discussion. I imagine your "bandsaw method" might be applied to a router table for cutting circles in thinner materials. With proper dust control, this would minimize the mess created by your hand-held "router method".

    0
    chefspenser
    chefspenser

    11 months ago on Step 8

    Well done, thank you for sharing and education me! Cheers!

    0
    rblume73
    rblume73

    11 months ago

    You could try a lazy susan with you band saw.

    0
    cheap132
    cheap132

    11 months ago

    Great post! I especially liked the table saw method.

    0
    bpark1000
    bpark1000

    1 year ago

    In my opinion, there is a hidden danger using the table saw method as you show. Of course, everyone knows that a table saw pushes back on the work, and that the work can jam against the blade, especially if the fence and blade are not set parallel, or the wood has locked-in stresses. When the work is a many-sided polygon, pinned at its center, any backward rotation will cause a jam against the blade, VIOLENTLY kicking back the work and sled, and possibly leading to fingers contacting the blade! I wouldn't even THINK about doing this without a guard in place, setting the blade as high as possible (to minimize the pushback tendency), and setting the guard as low as possible to just clear the work.
    Setting the blade high also gives truer cut when you get to the final "spin" pass.
    Your comment about bandsaw being limited in radius is true only to the extent you don't have room off to the side of the table. The clearance of the saw only limits the amount you can cut off IN ONE PASS. You can precut the corners off until you are less then that. You must set the pin carefully, accounting for the "lead" or cutting direction, or the blade will be pulled to the side, and produce a spiral and then jam. You can adjust for this by moving the sled forward/backward and making test cuts. Use a blade with a high tooth set. Avoid "thin kerf" blades. Set guides close and keep blade tension high.
    Another method to make circle is to first make template from scrap (using your's or other methods), fastening this to the work, and using router with follow-bearing against the template.

    0
    dwieland
    dwieland

    Reply 1 year ago

    I don't understand your concern about a hidden danger with the table saw method, unless you're basing it on trying to trim too aggressively on the final rounding pass. If that trim pass is taking off little more than the width of the blade, there's no chance of kickback. An advantage for the table saw is the relatively large supporting surface versus the small table of ordinary bandsaws, which makes it easier to get a square edge.

    0
    bpark1000
    bpark1000

    Reply 12 months ago

    You state that you are "uneasy" about the table saw setup. FOR GOOD REASON!
    When wood binds against the blade, it is pushed back. With usual table saw arrangement (wood getting pushed directly in, fence parallel to the blade), backward motion tends to relieve the bind, and there is no tendency for the work to rotate because the binding force is in line with the pushing force. But in your setup, the wood piece is pivoted about the center point of the circle, which is laterally offset from the blade, and connected to a massive sled. If the work binds the blade suddenly, the inertia of the sled will resist moving back. The offset force will cause the work to rotate about that pivot, toward the blade, causing the bind to get tighter, contacting the blade in the back. The only thing preventing this is the friction between the work and sled and your holding blocks, which is no match for the saw. The work will lift, and it and the sled will be shot back! Once the work is roughed out, the danger of binding is little as the blade is not embedded in the work. For all of the cuts, setting the blade as high as possible reduces the amount of pushback, and keeping the cuts short so the back side of the (up-moving) blade is not contacted (geometry more like the bandsaw setup). Having a guard in place "protects" the high-set blade and prevents the work from lifting. The high setting also makes the sled position easier to determine, and the final spin-cut truer.
    I hope you have Saw Stop on that saw!

    0
    dwieland
    dwieland

    Reply 11 months ago

    I don't think you intended the last comment as a reply to mine, but I agree that setting the blade high is important.

    0
    4DIYers
    4DIYers

    1 year ago

    I had to cut a circle for the well about a year ago, two pieces of plywood with poly insulation in the center. That was not fun cutting by freehand lol. Great tips, thank you for sharing!

    0
    SuperMagnetMan
    SuperMagnetMan

    1 year ago

    Thanks for sharing. For large circles I have used 2 dowels and one end has a rounded tip and the other I tape a marker on and use it like a giant compass and a hand held jig saw. However, now that I have a large laser cutter - I am spoiled:) It is just so easy to draw it and send it to the laser:)

    0
    RikkiePi4
    RikkiePi4

    Reply 1 year ago

    I agree, unfortunately I am not spoiled, so I use less or more what you suggest with hand held jig saw.
    For small circles I sometimes use hole saws lol. But you must have the right size of course, secondly there will be a drill hole left in the center.

    0
    SuperMagnetMan
    SuperMagnetMan

    Reply 1 year ago

    :) Great Instructable and I enjoyed watching it:)

    0
    ameerdb
    ameerdb

    1 year ago

    رائع جدا

    0
    Lee73
    Lee73

    1 year ago

    I like the router method, even for its mess - with a router you can also cut perfect large round holes. Years ago I needed holes to flush mount audio speakers, and a router was really the only practical way to get the two holes perfect....

    0
    Ironworxx1
    Ironworxx1

    1 year ago on Introduction

    Nice video, I really enjoyed it & your shop is so clean & everything us in it's place. On your router circle jig, try mounting a cord clip to keep from running over the cord. Maybe add a large hand on the small end to give you better control on the jig.

    Thanks,
    Mike @ Ironworxx Guitars

    0
    JavierL90
    JavierL90

    1 year ago

    Big fan of the bandsaw jig- so simple but so effective!!

    0
    Whyfrog
    Whyfrog

    1 year ago

    Just a question?
    Your methods are well explained and would make creating circles much easier. But do you have a method of cutting a circle in a piece of wood where the circle is NOT the object to be used.
    My daughter was asking me minutes before I saw your Instructables on creating circles easily with power tools.
    She wants to build a dog food bowl stand and wanted to know the best way to remove the wood so the bowls will be inserted in the shelf.

    0
    charlessenf-gm
    charlessenf-gm

    Reply 1 year ago

    Close is good enough for horseshoes, hand grenades and dog bowls.

    The bowls will have to have a LIP, right?
    The width of the lip covers a multitude of wavering.
    Use a jig saw if you've got one.
    Determine the diameter required. Then use half that and a compass with a pencil to mark out the circle representing the hole required by the bowl.
    (HINT: turn the bowl upside down and set it over the circle you just drew on your material to make sure our circle is not TOO LARGE!
    First drill a hole larger than the jigsaw blade somewhere inside the diameter of the hole required.
    Then drop the jigsaw blade into this hole and cut along the line you drew for the diameter of the hole required.
    Pop in the bowl to be sure of your fit, then assemble the top onto some supports to raise the affair to a height bowser finds most convenient.
    Finsidh to suit daughter or puppy - or leave au natural as I did.
    Note teh lighter color at the edge of the opening - where the sun don't shine - 'cause teh lip hid it!

    lip on bowl.jpg