# Small dia. circle jig

2814 Views 9 Replies 6 Participants Last post by  chessnut2
Doing a search here on the forum I came across this old post showing a DIY small dia. circle jig that may work for me! Router Forums - View Single Post - Small diameter circles.

I have a Bosch 1617/1618 EVS combo with a RA-1054 edge/circle guide, Just wondering if anyone has made an adapter (like pictured in the linked post) for the RA-1054 to make smaller than 4" dia circles?

Doug
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If you are talking about making the hole all the way thru, I just use a hole saw.
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On the few occasions where I needed to route circles smaller than 4 inches, I would do this. Set the router circle jig to make (for example) a six inch circle and cut that out of a piece of stock. Throw the circle away and use the remaining/resulting "donut hole" as an edge guide. Put the router inside the donut hole and follow the inside edge. You can get as small a circle as you can do the math for by making your own circular edge guide. Did I explain that okay?
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If you are talking about making the hole all the way thru, I just use a hole saw.
Yeah to bad it wasn't that easy!

I'm looking to make some trunnions & matching radius grooves for a tilting table on a disk sander.

Doug
Put the router inside the donut hole and follow the inside edge. You can get as small a circle as you can do the math for by making your own circular edge guide.
Yeah that could work, As long as I could figure out the math needed correctly.

I would need to figure out three different size patterns, One for the inside radius, One for the outside radius, Then one for the matching radius groove.

Doug
Maybe this thread will be helpful: http://www.routerforums.com/general-routing/31313-circle-trimming.html The world's simplest circle jig is described in post #2.
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Chuck,

Thanks for the link & moving my post!

Doug
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Are you one of us who bought a CRB7 jig? These are similar to the one in your link, but can do many other things as well. Since I have a CRB7 I would use it instead of making one. The Jasper circle jigs are also very handy for cutting circles of many sizes with a router.

Charley
Are you one of us who bought a CRB7 jig?
No not me, However I have thought about getting one?
Just trying to justify the cost since my Bosch RA105 will do a lot of the same functions as the CR87.

Doug
No not me, However I have thought about getting one?
Just trying to justify the cost since my Bosch RA105 will do a lot of the same functions as the CR87.

Doug
I've been wanting the CRB7 also. It costs a lot, but when you need it, you need something that's fairly safe.
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