# Quick Fixed-Base Circle Question



## bfrance101301 (Jul 4, 2008)

Quick question:

I just picked up a Bosch 1617evs fixed-based router at the HD rental tool sale for $94.00.

Seemed like a good deal for the price, and I fabbed up a circle jig from a piece of 1/4" plexi to cut some mdf rings to mount speakers on my a-pillars in my car. But, I have encountered a problem with it that I'm trying to figure out how to work around. Here's the issue:

The outside diameter of the speaker that I'm trying to use is 4 1/8" (per the PartsExpress catalog I have). With the radius of this being 2 1/16", the pivot point to use the router for this falls right under the fixed-base of the router.

How do I cut circles with a fixed based when the radius of the circle is underneath the fixed base?

I attempted to drill 4 holes through the 1/2" mdf that I was using, but this caused problems with part of the outside edge of the ring having a notch out of it at one point.

Any ideas? Or, am I just stuck until I can come up with the $$$ to pick up the plunge base kit for this router?

Thanks in advance for any input or ideas!

-Ben


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## nzgeordie (Oct 22, 2006)

Ben, there are lots of "small circle jigs" from forum members. Try entering that in the search engine at the top of the page and you'll get lots of ideas. I made the one posted by reible and it worked a treat.


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## Mike (Nov 22, 2004)

Ben, you can do this job easily with a template and a guide bushing or a bearing guided bit. Use a piece of hardboard or plastic that is 1/4" thick, trace around your speaker for the size and cut out the center. Position this on your wood with some double sided carpet tape. Drill a hole through the wood slightly into the center, large enough to accept a 1/2" bearing guided bit. Insert your bit and move it to the edge and make your cut. If you use a guide bushing your template hole will need to be the proper amount larger. In this case you will drill your hole and use a straight bit.


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## kp91 (Sep 10, 2004)

You can also use a router compass to cut circles smaller than your router base. Take a piece of 1/2 inch stock wide enough to give you a good base and drill it to accept a template guide that you have.

Chuck up a small diameter bit and figure out what radius you need for your hole. Drill a corresponding hole in your compass. Drive your pivot pin in, set the compass on the pivot. Set the router in the compass and you're good to go.

I have also used a plexi compass that I would bolt onto the router, but it was difficult to use for cutting circles smaller than the baseplate since I could not see the hole I was trying to line up on the pin. Using the template guide method works because I can be sure I've lined up the right hole on the pin. It also keeps the cord from getting twisted up when making multiple passes to cut all the way through.

--sorry, didn't read that you only have a fixed base router. I don't know how the bosch does depth adjustment, but it might work. Start the router with the bit above the work, release the clamp and lower the bit into the stock, tighten the clamp and make your first pass. If uncomfortable with that, then Mike's approach is the way to go.--


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## jerrymayfield (Sep 25, 2004)

Drill a hole in the base plate that is the correct radius from the center of the bit,and use this as your pivot point. Hope this makes sense.

Regards

Jerry


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## harrysin (Jan 15, 2007)

As you don't have a plunge router, I think that a jig saw might be the best way to go for this "one off" project. If you intend to carry on with serious woodworking, then a plunge router is, in my opinion, a necessity.


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## bfrance101301 (Jul 4, 2008)

Thanks for all of the suggestions, I really appreciate it.

I took yesterday off from my projects due to the holiday, but I'll be working on fab'ing up a jig today. I'll let you all know how it turns out.

-Ben


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## jjciesla (Oct 20, 2007)

For a one off hole you might consider a circle cutter. With it you can make circle templates quickly.


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## bobj3 (Jan 17, 2006)

Hi quote=bfrance101301

One word
JASPER, use with a plunge router or a standard base 


http://www.soundlabsgroup.com.au/c/Jasper/Jasper+Circle+Jigs.html
http://www.soundlabsgroup.com.au/p/JA-200/Jasper+Tools+200+Circle+Jig
http://www.amazon.com/s/ref=nb_ss_e?url=search-alias=aps&field-keywords=jasper+jig&x=0&y=0


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bfrance101301 said:


> Quick question:
> 
> I just picked up a Bosch 1617evs fixed-based router at the HD rental tool sale for $94.00.
> 
> ...


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## pal (Feb 13, 2008)

A bit late but here is an adjustable circle cutting jig from Patric Spielman. I have built this jig to use on a Bosch GOF 50 works like a charm, will cut circles from 1" to 7 1/2" 

Regards

Pal


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## bobj3 (Jan 17, 2006)

Hi Pal

I think router is my name made one like that one, he likes it alot.

http://www.routerforums.com/jigs-fixtures/6699-new-ccj.html


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## harrysin (Jan 15, 2007)

See next post


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## harrysin (Jan 15, 2007)

And still another circle cutting jig which is infinitely variable from about 1 1/8" hole. Simply draw a circle and set the cutter to just touch it, inside if you want the hole, outside if you want the centre!


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## bobj3 (Jan 17, 2006)

Here's one I made that can do many,many router jobs,, a all in one thing 
b/4 I got the Jasper jig to do the circles ..now I can do 2 1/4" to 18 3/4" circles, easy and quick with one jig..


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## pal (Feb 13, 2008)

Here is another Circle cutting jig called Router Buddy. Cuts circles from 2 to 18 3/8" diameters. Fence: Mounts on trammel slide, is adjustable from 0 to 8 1/2", for cutting rabbets, dadoes and more on both straight and curved edges. can also get an elliptical jig for it. if anyone is interested go topractical-technologies.com

Regards 

Pal


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## harrysin (Jan 15, 2007)

A very fine jig Bj., albeit rather complex to make. With all the games currently on the forum, perhaps we should have one showing circle cutting jigs, I could dig out at least another two.


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