# Cutting A CIRCLE with my router



## jhg2 (May 12, 2012)

I would like to rout about a 6 1/2 in. wood circle to mount a wall lamp. My router is a Sears 315.174451. Can anyone suggest a circle guide or confirm that I could use a simple circle guide made from from something like 3/8's masonite to replace the base plate? I have been thinking about using a short piece of 1/4 or 3/6 in dowel as the pivot point. I am open to suggestions.

Thanks 

John G.


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## Chris Curl (Feb 13, 2012)

welcome to the board john. there are lots of ways to skin that cat, here are the first 3 i looked at

http://www.southpointhawaii.com/include/pdf_files/cmp-plansnow-routerjig.pdf

DIY circle cutting jig for your router - YouTube

How to Make a Router Circle Cutting Jig

they are all pretty similar. 

if you have a router table with a t-track, there are options for that too where you put the board on a pin that is the deisred distance from the bit and you spin the wood over the stationary router bit, like this:

http://www.routerforums.com/100137-post33.html


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## jw2170 (Jan 24, 2008)

Hi John,

There are many examples of circle jigs on the forum. Do a search for "circle jigs"...

http://www.routerforums.com/jigs-fixtures/22505-my-circle-jig.html#post193297


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## harrysin (Jan 15, 2007)

jw2170 said:


> Hi John,
> 
> There are many examples of circle jigs on the forum. Do a search for "circle jigs"...
> 
> http://www.routerforums.com/jigs-fixtures/22505-my-circle-jig.html#post193297


Here is a pdf showing the making of a simple router circle jig that I presented some time ago.


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## jhg2 (May 12, 2012)

Thanks to all for the suggestions. I guess the hardest cut is always the first! After looking at a few jigs, I said "I can do that." Down to shop and found some 3/16 ply left over from something I can't remember. The jig is cut. I left it rectangular cause I could. Pulled the base off the router for a template and all 3 holes are marked and one is drilled. I think a trip to the hardware store for some 1/8 in dowel and I will be cutting circles with the best...Well, nice ones anyway. Thanks again to all for the suggestions and the push


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## Mike (Nov 22, 2004)

John, you can use a large brad or a small finish nail as the pivot point.


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## jlord (Nov 16, 2009)

Finish nail or a double head nail works great as a pivot point


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## jw2170 (Jan 24, 2008)

jhg2 said:


> Thanks to all for the suggestions. I guess the hardest cut is always the first! After looking at a few jigs, I said "I can do that." Down to shop and found some 3/16 ply left over from something I can't remember. The jig is cut. I left it rectangular cause I could. Pulled the base off the router for a template and all 3 holes are marked and one is drilled. I think a trip to the hardware store for some 1/8 in dowel and I will be cutting circles with the best...Well, nice ones anyway. Thanks again to all for the suggestions and the push


Good to see you got the result you were after.

The basic circle jig is probably one of the easiest and simplest router jigs to make..

As harry suggests, mark your circle with a pencil and compass and make sure your bit is on the inside of the line as you want the hole and not the disk...


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## Chris Curl (Feb 13, 2012)

John, the only possible problem I might see for you with the jig that moves the router (as opposed to the other jig that moves the board across the stationary bit) is that the size of the hole you want to cut may be smaller than the minimum circle diameter that the the jig can cut.

For a 6 1/2" hole, the outside edge of the bit would need to be 3 1/4" from the pivot point. That 3 1/4" is pretty small compared to the minimum distance the bit can be from the pivot point on the jig. Given the size of a typical router base, you might not be able to get the pivot point close enough.

The other jig (the one that moves the board across the stationary bit) is capable of cutting smaller circles.


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## jw2170 (Jan 24, 2008)

The Jasper circle jig (model 400) will cut circles from 1"..... I am sure a home built one could do the same...


http://www.jaspertools.com/products...&prod=Model-400 Circle Guide&cat=Circle Guide


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## bobj3 (Jan 17, 2006)

Hi John

That will work just fine, a real KISS way to get the job done>>>

==



jhg2 said:


> I would like to rout about a 6 1/2 in. wood circle to mount a wall lamp. My router is a Sears 315.174451. Can anyone suggest a circle guide or confirm that I could use a simple circle guide made from from something like 3/8's masonite to replace the base plate? I have been thinking about using a short piece of 1/4 or 3/6 in dowel as the pivot point. I am open to suggestions.
> 
> Thanks
> 
> John G.


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## jschaben (Jun 21, 2009)

jw2170 said:


> The Jasper circle jig (model 400) will cut circles from 1"..... I am sure a home built one could do the same...
> 
> 
> Jasper Tools - Circle Guide Model-400 Circle Guide 673046004006


You're right James, this one works very well. If I were to do another from scratch though, I would likely go with 1/8" increments and pick up the 1/16" with a bit change from 1/4" to 3/8". I swiped one of Bj's ideas and use a half inch bushing to attach the router.


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## jw2170 (Jan 24, 2008)

jschaben said:


> You're right James, this one works very well. If I were to do another from scratch though, I would likely go with 1/8" increments and pick up the 1/16" with a bit change from 1/4" to 3/8". I swiped one of Bj's ideas and use a half inch bushing to attach the router.



That also is one of my upcoming projects...


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## jhg2 (May 12, 2012)

I have the jig mounted after removing the base. I do have an extra set of mounting holes (well sorta extra) after mis-measuring or placing the first mounting holes. James, Thank you for the reminder on the radius. I had thought about that but it got lost somewhere in the shop. ( I do need to pick up stuff) With luck and a little time, I will have it done this afternoon. My plan was to cut the circle and then use a round over bit to give it a nice edge. I am having second thoughts about that because if I comepletely cut the circle, i will have lost my clamping edge. so the plan is to cut the edge about 3/4 of the depth and then apply the round over before cutting through to free the scrap.


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## jhg2 (May 12, 2012)

I am still learning!

I drilled a piece of scrap to see how my jig worked. I drilled the hole for the pivot 3/16 dowel and gently tapped it in. So the pivot point was tilted slightly after I checked the piece I had used as a test a 12 in (approx) long by 3/4 in 2 in. The removal was slightly canted and I checked the pivot with my tri-square and it was tilted. Hmmm. I did go and check my drill press to see if the table was 90 to the drill and it was. So now I have to figure out what I was doing to cause that cant. Is is possible, because I was starting with a square end, that the router bit climbed a bit> (bad choice of words there!) So I plan to take a deep breath, get a glass of iced coffee and think about this!


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## Chris Curl (Feb 13, 2012)

is the tilt concentric (ie always tilted toward or away froom the center of the hole)? that might indicate that the jig is not flat


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## jhg2 (May 12, 2012)

I don't know? I will have to check that tomorrow. I also starting thinking that I might have used to thin a dowel for the pivot. Thanks for the thought.


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## jhg2 (May 12, 2012)

Chris Curl said:


> is the tilt concentric (ie always tilted toward or away froom the center of the hole)? that might indicate that the jig is not flat


Maybe I am doing things backwards? I have a piece of flat stock (1 x 4 in) and I drill a 3/16 hole in the stock using my drill press. It is about 1/4 in or so deep and centered on the width. Then I insert the pin (piece of 3/8's dowel) and tap it gently to insure that it is seated. Then I drop the jig onto the pin and make several passes across the stock, clockwise, then lift and repeat for more depth of the cut. I have noticed that the cut is not quite as circular at the top as it is on either side. 

If it would help, I will grab my camera and take a few pictures. What size pictures are acceptable on this site?


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## Chris Curl (Feb 13, 2012)

not sure about size restrictions on pictures. i think the attachment manager has info about that when you open the window.

is there any play between the hole in the jig and the dowel? or maybe the dowel rocks a little side to side as it is pulled by the router?

are you keeping the center part? if not, then to be 100% sure, you could glue the dowel to make sure it stays put.


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## jhg2 (May 12, 2012)

Well, the deed is done and I have a circle and a little more experience. This second run at the job was well worth the time. I used some scrap materials and now possess my very own home made 6 in. circle.

I did find that just clamping the wood I was cutting had it's own problem. I cut a 7 in. square from a piece odd plywood and then found that clamping the raw piece directly blocked my ability to cut around 360 deg. The solution was to take about a 14 in piece of 1 x 4 and screw the square to the center of the 1 x 4 on a diagonal. That was then clamped to the table After that, all went smoothly and I now possess my own homemade circle.

A few thoughts came up. One ws that I could switch to a small round-over bit before the circle is cut free and clean up the top edge. The bottom (last cut) edge was a bit nasty also but either an application of sharp chisel or maybe sandpaper would cure that.

Thanks to all for the support and suggestions.


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## jschaben (Jun 21, 2009)

jhg2 said:


> Well, the deed is done and I have a circle and a little more experience. This second run at the job was well worth the time. I used some scrap materials and now possess my very own home made 6 in. circle.
> 
> I did find that just clamping the wood I was cutting had it's own problem. I cut a 7 in. square from a piece odd plywood and then found that clamping the raw piece directly blocked my ability to cut around 360 deg. The solution was to take about a 14 in piece of 1 x 4 and screw the square to the center of the 1 x 4 on a diagonal. That was then clamped to the table After that, all went smoothly and I now possess my own homemade circle.
> 
> ...


Hi John - If you "onion skin" that last cut you will be able to maintain control of the fall off. By onion skin, you set the depth of cut to leave a 1/32" or less material to hold the disc in place. That is thin enough to just punch out the disc and clean up the edge by other means. Alternatively, you can pin nail or use double side tape to hold the disc while you finish the routing operation.


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## mpIX (May 30, 2013)

jschaben said:


> Hi John - If you "onion skin" that last cut you will be able to maintain control of the fall off. By onion skin, you set the depth of cut to leave a 1/32" or less material to hold the disc in place. That is thin enough to just punch out the disc and clean up the edge by other means. Alternatively, you can pin nail or use double side tape to hold the disc while you finish the routing operation.


I'd go with "onion skinning" it then create a hole in the onion skin to fit a straight bit/roller to clean up the edge so no splintering from punch out.

Btw, here is a circle jig i made specifically to target holes ~6.5" diameter and then some - 
Based many on positive user reviews i had purchased a Jasper Jig from Amazon for ~$60 and was very disappointed with what i got and how it functioned. Sent it back the next day! My jig cost me under $10 to make, i got the plexiglass from the scrap bin at a local plastics store. I can easily micro adjust on the fly while in use, a real plus for my needs in making loudspeaker driver cutouts to flush mount the drivers frame, something which would've been a pita with the J. jig, not to mention the J. jig is only adjustable in specific set increments :\


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## Quillman (Aug 16, 2010)

Covers all radii from .75" - >18".


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## mpIX (May 30, 2013)

Quillman said:


> Covers all radii from .75" - >18".


Great link, thanks!


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