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Cutting a circle [message #44559] Mon, 03 May 2004 12:48 Go to next message
Tom Flahavan is currently offline  Tom Flahavan
Messages: 13
Registered: May 2009
Chancellor
I am building studio towers. I need a tip on cutting out the 9 1/8 inch circle. How do you make it perfect? I am useing a hole saw for the 2 3/4 and the 4 1/2 inch cuts. Any tricks out there?

Re: Cutting a circle [message #44560 is a reply to message #44559] Mon, 03 May 2004 13:30 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18683
Registered: January 2001
Illuminati (33rd Degree)
Use a hole cutter like this:

Tool shops have 'em in various sizes, so you can probably find one locally. But it is sometimes hard to find cutters that go bigger than 8". Many of them use a sling blade, and I like that approach but you don't find those going very large. Click on the photo above and you can buy a tool that cuts holes up to 12" for sixty bucks.

Re: Jasper Jig [message #44562 is a reply to message #44559] Mon, 03 May 2004 15:41 Go to previous messageGo to next message
Matts is currently offline  Matts
Messages: 359
Registered: May 2009
Grand Master
If you have a router, get a Jasper Jig- it will cut perfect circles easily. Totally accurate and very easy to use. They sell them at Parts Express and buches of other places.

Re: Cutting a circle [message #44564 is a reply to message #44559] Mon, 03 May 2004 16:26 Go to previous messageGo to next message
Tightwad is currently offline  Tightwad
Messages: 41
Registered: May 2009
Baron
Carefully mark the circle.

Use a jigsaw, but err a bit on the inside.

Use a rasp to get the rest.

Re: Fer a buck 2 skeventy-eight you can buy....... [message #44566 is a reply to message #44560] Mon, 03 May 2004 20:13 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
.....a scrap piece of 1/4" plywood and a nail.
That plastic or phenolic or whatever base on your router is designed to be removable.
Take it off, copy the screw hole placement onto the 15 or 20 inch long piece of plywood by wide enough to hold the screws for the base. Use your 2 1/2" hole saw to make the hole for the router bit and attach the plywood (it is now officially called a Trammel) to the router.
Draw the circle with a compass. Put the outside edge of the cutting bit on the circle and find the center, mark it on the trammel and push a nail through the trammel and into the center hole. Push, plunge or whatveer the router into the wood, rotate.
Or do what I did, as per Wayne's advice, having made too many trammels over the years I got lazy and bought the Jasper.

Re: Cutting a circle [message #44569 is a reply to message #44559] Tue, 04 May 2004 13:25 Go to previous messageGo to next message
jeffh is currently offline  jeffh
Messages: 6
Registered: May 2009
Esquire
A router and circle jig is the best way. However, I now a good router will cost at least $100 and then $20+ for a circle jig. See my attached link to see my router, Jasper jig and homemade jig. I have attached a link to a subwoofer that I built. Just go to page 3 and you'll see the jigs.
http://europa70.tripod.com/diy_sonosub001.htm

Re: Cutting a circle [message #44583 is a reply to message #44559] Sat, 08 May 2004 08:35 Go to previous message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)
Of course you can use a router as some have suggested, but unless your flush mounting the drivers where you need to make a rebate, then a jigsaw will work fine. Mark the hole out with a compass and pencil, and cut it out with a jigsaw - since the driver mounts from the front, you cant see if the hole is slightly imperfect and it wont affect anything if it is, you'll be cutting right on the line anyway.

Jigsaws in Australia cost as little as AU$20, so I'd guess thats about US$17. You dont need a fancy one, the cheapest one available will work.

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