Thread: Circle Jig

David these are easy to make and have been covered in the forum a search should find a plan.

In fact here's one for sale https://www.woodworkforums.com/f221/r...er-jig-124261/

Here's another (DIY): https://www.woodworkforums.com/f88/router-compass-50372/

Cheers,
Joe

Joe what are the minimum and maximum dimensions you can cut?

I think I might just have to try this. I have seen a few different ideas that I might try but we will see.

I will have to try and make something where I can quickly change the setting to whatever dimensions I need. I will be cutting a lot of circles anywhere from two inches to 22 inches. And maybe someday I will be able to try and make a round table so who knows what size for that but I am mainly just using this as a speaker hole cut out.

The minimum is limited by the router base, probably about 6.5" (165mm) diameter, with the point-side bushing removed. For smaller diameters, an adapter plate would work better, even though it reduces the bit projection. But for circles in the neighborhood of 2 inches, consider drilling with Forstner bits instead.

I haven't pushed the envelope on the largest, but the 3/8 all-thread is stiff enough to use the full length of the bar - could be up to about 5 feet diameter, with a 3-foot length of all-thread. With an adapter coupling to a larger bar, or attachment to thicker material, no limit I can think of.

In a previous life, and without the router, I've used trammel points attached to timber to accurately and precisely swing arcs up to 12-foot radius.

Cheers,
Joe

Good Morning David

Good advice above. Even cheaper is to simply screw the router to a piece of MDF or plywood, put a nail through the MDF the desired radius from the router bit, and you have a near zero cost jig.

Also you need to think through your routing technique before you attempt to cut circles with a jig - also whether you want to cut circular discs or a circular hole or both. Once you have cut around the disc it is detached from the larger sheet material and is no longer stable. The router is pivoting on the centre of this disc and if the dic moves laterally (and it will) then the router will move perversely and your circle will not be round.

The simplest solution is to put you material on a sacrificial sheet of chipboard, or similar, and make sure that the centre pin in firmly anchored in this underlying base sheet.

Cheers

Graeme

PS: Do not forget operator safety. After the circular saw, the router is probably the most dangerous tool in our arsenal.