Circle cutting jigs

Basic router jig......

roger lance

This jig was just made and has not been used. Jig is best used with a plunge router......

Jig can be made as big or small as you desire.

string on centered nail tied to plunge router?

I've made them a couple ways,

Keith Newton

One is about like Rogers post, where I drill a hole through usually 1/2" plywood that I drill the hole for a guide bushing in the base of the router.

Another way is to remove the fence portion from the bars of the edge guide, then screw that portion with the bars onto the end of the trammel arm. This will give about 8" of easily adjustable length.

When your using the router to hog off a lot of wood, go clockwise, to the bit is pulling away from the center if that is the keeper part, then on the last plunge where only taking a small amount, reverse that, and go counter clockwise. This will clean up any evidence of the steps of the different plunge levels. And of course , if you are keeping the concave arc, do the opposite.

For things like table tops, rather than screw into the center of the actual top, I usually make a 1/2'' MDF template rather than screw into the center of the actual top.

Thanks

JL

Works for the router. I could also make a "shoe" to attach to the jig and use it with a jig saw.

Re: Circle cutting jigs

Walt

For those with more money than time there's the jasper jig.

Re: Circle cutting jigs

Jim Dillon

JL, here is a picture of a router jig I made years ago based on an article in a woodworking mag IIRC. I also have a plastic one like Rogers, but have never used it. The pivot point is a cutoff nail. The only downside is that humidity changes sometimes make the slider hard to move. Otherwise, it met my needs at the time. I have a similar setup on my bandsaw.

Nothing for my jigsaw. Jim

Re: Basic router jig......

John McGaw

I have a close twin of the one you show. Mine was made from a scrap of 1/4" tempered hardboard on the spur of the moment. Later I prettied it up by rounding the corners and permanently mounted a PC base to it. It as worked for everything I have needed and the idea could be easily extended to an 8-foot radius (although I'd need a new shop or I have to work in the driveway to manage that).

Re: Circle cutting jigs

William Duffield

I have one like that too. My fuzzy recollection is that the plans came from Bill Hylton's Router Magic. For mine, I made two of the sliding bars of different lengths, and could easily make another if I needed a circle of very large radius.

Other advantages of this design are:

• You don't need to make room for the long arm of the jig on your bench when you are routing small circles;

• The radius of the circle is very finely adjustable, so if you need a new radius less than a quarter of an inch different from a previous radius, you don't need to make a new jig because the new pin hole would overlap a previous hole;

• It works for Metric and Imperial circles. I mention this because I've seen commercial circle routing jigs with hundreds of holes in them. This one doesn't rely on the precise concentricity of the router bit and the center of the jig, since you make a direct measurement of the distance between the bit's cutter and the jig's pin to set it up.

• You can turn the arm around and set the pin well under the router base, very close to the router bit, for cutting small circles.

Re: Circle cutting jigs

Jim Dillon

Bill, your "fuzzy" recollection is spot-on. It WAS Hylton's Router Magic book! Out of curiosity, I just checked and some scribbled notes of mine are on the pages for that jig. Thanks for your reply. As an aside, that book (despite the hokey title) is a favorite of mine. Jim