# circle jig... To buy or make?



## davester84 (Aug 28, 2012)

I want to build a thein separator for my DC. I need to cut a circle to do it. 
Should I build my own jig somehow or would it be a better idea to buy one for my router from somewhere for around $50.

If I should build it, does anyone have any good plans. And if you think I should buy it, does anyone have experience with one they recommend I buy? 

Thought I'd ask you guys since I have never done this before. 

Thanks


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## J Thomas (Aug 14, 2012)

Here's one plan you might consider. I'd make one & save the cash for something I couldn't make.
..Jon..

http://www.woodworkingtips.com/etips/etip102000sn.html


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## cabinetman (Jul 5, 2007)

Other than using a router as suggested, you can make one on the table saw, band saw, or with a jig saw.









 







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## davester84 (Aug 28, 2012)

cabinetman said:


> Other than using a router as suggested, you can make one on the table saw, band saw, or with a jig saw.
> 
> 
> 
> ...


Table saw??


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## cabinetman (Jul 5, 2007)

davester84 said:


> Table saw??


There's discussion in this thread.
http://www.woodworkingtalk.com/f2/table-saw-bandsaw-router-jig-saw-42957/









 







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## Pirate (Jul 23, 2009)

An easy jig to make. It's a jig you will use now and then.
The one I made, has a removable arm with pivot, which can be reversed or replaced with a long one for big arcs.
Bottom view in picture.


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## davester84 (Aug 28, 2012)

Pirate said:


> An easy jig to make. It's a jig you will use now and then.
> The one I made, has a removable arm with pivot, which can be reversed or replaced with a long one for big arcs.
> Bottom view in picture.


This looks like a good idea. What kind of wood did you use? How did you cut out the shape? How do you fix the arm so it doesn't move after you set the length? I need to make a circle big enough to cover a 30 gallon garbage can... Think this would work? 
If you could post a few more detailed photos I would appreciate it... I am new at this stuff.


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## jschaben (Apr 1, 2010)

If you are just going to use it for the baffle construction, I'd go with J Thomas suggestion. Make one from scrap for the largest radius you will need and just add pivot holes along the centerline to accomodate all the radii of the project.:yes:


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## Pirate (Jul 23, 2009)

davester84 said:


> This looks like a good idea. What kind of wood did you use? How did you cut out the shape? How do you fix the arm so it doesn't move after you set the length? I need to make a circle big enough to cover a 30 gallon garbage can... Think this would work?
> If you could post a few more detailed photos I would appreciate it... I am new at this stuff.


I used some used 

I used a used piece of 3/4 maple ply, I scrounged off something. 
I cut a wide t-slot in it, for the pivot arm to slide in. The knob, has a threaded stud, that screws into a t-nut (type with prongs)
The threaded stud, when tightened, pushes down on the pivot bar, locking it in place.
Here is a top picture.


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## davester84 (Aug 28, 2012)

Pirate said:


> I used some used
> 
> I used a used piece of 3/4 maple ply, I scrounged off something.
> I cut a wide t-slot in it, for the pivot arm to slide in. The knob, has a threaded stud, that screws into a t-nut (type with prongs)
> ...


The only part that I am a little confused on is how you attach the end of the pivot bar to your work piece. I don't see a hole in the end of it. I assume a nail would work? Or would that wiggle its way out as I go around the circle?


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## Pirate (Jul 23, 2009)

davester84 said:


> The only part that I am a little confused on is how you attach the end of the pivot bar to your work piece. I don't see a hole in the end of it. I assume a nail would work? Or would that wiggle its way out as I go around the circle?


If you look close, you can see the pivot nail, in the end of the arm.
I made a longer arm, with a dogleg in the end, so I could hot glue a pivot block, with a small hole for the nail, to the workpiece, so I could cut circles, without putting a hole in the piece.


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## GROOVY (Apr 27, 2008)

I made a longer arm, with a dogleg in the end, so I could hot glue a pivot block, with a small hole for the nail, to the workpiece, so I could cut circles, without putting a hole in the piece.[/QUOTE]

dangit man that there is a good idea, I appreciate the idea


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## Dejure (Sep 2, 2009)

I built my own. After looking at those for sale, it seemed a better way to go, since my design offered increased capacity and more comfortable use.

I extended the bed well over to the left of my blade. First, this helped reduce the tendency of the jig to tip, when doing larger circles (e.g., 36"). Second, it reduced the amount of saw dust. Having the jig stop at the blade allows the saw to toss a lot of dust into the air from the left side of the blade.

I extended the [aluminum] guide about five inches out the back and added a stop to the operators side. The extended guide gets me on track early. The stop positions the start of my spinning cut at the leading edge of the blade , exactly in line with the pivot, avoiding binding of the blade.

The guide and stop allow me to toss an over-sized or rough cut piece of material on the jig, run it into the blade, and begin spinning when I reach the stop. This vastly improves the jig functionality.

I should add that I used factory aluminum channel for my guide pin track. The Aluminum guide for the band saw track was from 3/8 aluminum stock from a metal supplier. A four foot long piece a few inches wide will give several 3/4" x 3/8" bars for jigs at a fraction of the downtown price. They cut easily on the saw (I used a sixty tooth blade).

I'll be running across town and will try to remember to grab a photo when I get to the shop, in case my ramblings are less clear than usual.


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## mengtian (Nov 8, 2012)

I just bought my router two weeks ago and made perfect circles with a home made jig from a piece of scrap plywood. Took all about 5 minutes to do. I did 24 " and 36 " circles for a float. I don't see the need for buying one..but thenagain I am new at this


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## Dejure (Sep 2, 2009)

*Nice results*

I've used a couple of my routers to make circles and was pleased with the results. The only thing I didn't like was how much material I had to go through to router the circle and the work the bit was made to do. As such, I stay with the band saw, but might use a router to clean up the last fraction of an inch, if needed.


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## jschaben (Apr 1, 2010)

Dejure said:


> I've used a couple of my routers to make circles and was pleased with the results. The only thing I didn't like was how much material I had to go through to router the circle and the work the bit was made to do. As such, I stay with the band saw, but might use a router to clean up the last fraction of an inch, if needed.


If I'm going through anything very thick, I'll just put a groove about a 1/4"" deep with the circle jig, cut along that line with the bandsaw and use a flush trim bit on the table to clean it up. The walls of the initial cut leave a nice smooth surface for the flush trim to ride on, circle is accurate and not so hard on the router or bit. Doesn't really take much more time either. :smile:


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