How do I cut a ring?

[Jimmy Williams]

My New Years resolution for 2008 was to get serious about dust collection so I got LOML to agree to let me purchase a Wynn canister for my Jet 1200. According to the Wynn site, I will need to cut a ring to sit on top of the collector in order to mount the canister.

I have a piece of 3/4 MDF ready to be used for the ring and a router trammel ready to go, but I can't seem to figure out how to cut the inner circle. I plan to rough cut the outer circle on the band saw and then use the trammel to finish cut the outside of the ring. Will the inner circle stay stable enough to cut the inner diameter of the ring (except for the last little bit where I finish/start the cut)?

I plan on using a 1/4" straight bit and was thinking that I could place 1/4" dowels in the cut as I go, in order to stabilize the inner circle.

Would this work or am I over complicating this?

[Dave Watkins]

I would probably do the outer then go at the inner but stop about an 1/8" shy of cutting all the way through. Then use a jigsaw to follow the edge to complete.

Good luck,

Dave

[Ken Fitzgerald]

Draw it out on the mdf ....then strategically place some small finish nails to hold each of the future pieces to another piece of wood....say more mdf or plywood. Router the outer and the inner cuts.

[scot geysbeek]

Jimmy,

Screw a scrap piece of plywood or MDF or what ever to the underside of the ring you are trying to make, and that will hold everything in place while you use the router to cut the inside circle, just make sure that the screws do not fall in the path of the router bit.

[fred woltersdorf]

just had a thread on this last week. setup looks pretty slick, something i'm going to try.http://www.sawmillcreek.org/showthread.php?t=72558&highlight=cutting+circles

[Chris Padilla]

Jasper (http://www.jaspertools.com/) makes some awesome circle cutting jigs for the router. Well worth the money IMO. Just google "jasper circle jig" and you'll see the various outfits selling them and their prices. They have great customer support as well. I broke something and they simply mailed me a new one no muss, no fuss.

[Lee Schierer]

just had a thread on this last week. setup looks pretty slick, something i'm going to try.http://www.sawmillcreek.org/showthread.php?t=72558&highlight=cutting+circles

What I liked about that thread was the idea of using pieces of dowel in the cut to keep the ring from moving as you approach the end of the cut. I've used double sided tape to hold the tramel center in place on a backer board to make inside circle cuts for clock faces. It works pretty well.

[Mike McCann]

after cutting the outer ring and you start routing out the inner ring when you get ready to cut all the way through just clamp behing you as you go so the ring does not drop.

[Jimmy Williams]

Great advice Ken. I will have to drill some holes to mount the canister to the ring anyway so I could use the holes as mounting points to the spare MDF or plywood.

Thanks for the responses

[Doug Shepard]

I'd do both the inner & outer circles with the MDF on top of another scrap piece of ply or MDF. Just drill & countersink some screws through the inner circle into the scrap piece. Countersinking keeps everything out of the way for the trammel arm. The dowel approach works but for a one-off project it's probably easier to just screw it down.

[Chris Padilla]

Interesting on the hold-down ideas. I just use my hand but then I think I've only cut one or two rings in my life and they were for my DC build.

Pick up a 1" - 2" thick piece of insulation foamboard (at Lowes or HD) and you'll find TONS of uses for it. One 4x8 sheet of this will last you quite a long time.

[Mike Cutler]

Jimmy

Yes it should work just fine.
Set up your router to make light cuts and progressively cut the inside of the ring. I would actually use the router to do both the inside and outside of the ring. Outside first, then inside.
A sheet, or roll of double sided sticky tape should hold everything in place while you are cutting. You may also elect to flip the material over and finish the routing of the inside and outside circles.

[M Toupin]

Use a router trammel to cut the circles. The problem making rings is that the inside moves around on the final cut through and messes up you ring. To solve the problem you need to hold everything firm while cutting the rings. Take a couple of crap pieces of whatever you have on hand and hot melt glue them to the back side of your piece. Glue them so they intersect both the outside and inside of your ring. The idea is to hold moth the ring, the center and the outside firm while you cut. The hot melt will hold everything firm while cutting, but pop right off when your done. Keep it simple, there's no need to make it any more complicated than it is.

Mike

[Jon Bonham]

When I use my Jasper jig, I just screw the middle down to a scrap piece of mdf I keep for cutting circle on top of. If I'm cutting a ring, I cut the outside first. Then I pin nail through the portion of the ring that I'm keeping. Then I countersink a couple #8 holes in the inside throwaway portion of the ring. Then I cut the inner portion of the ring. The pin nails hold the ring and the screws hold the scrap. I use a 1/4" spiral upcut bit in my Porter Cable 690.