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Thread: Cutting Small Circles???

  1. #1

    Cutting Small Circles???

    So...I'd like to cut some circles and I need them to be clean circles, about 2 to 4 inches in diameter. I could use a jig saw and sand to the line, but I'd really like them to be super clean circles. Ideas?

  2. #2
    Join Date
    Apr 2013
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    Hole saw if they come in the correct diameter, adjustable circle cutter for a drill press, or use a router with a circle cutting jig or circle template.

  3. #3
    I am a fan of using a router for what you are describing. Do you have a plunge router and template guide bushings?

    There are at least three or four ways to do it cleanly and precisely either with the center hole, or without.

    Another way is to make a 3 minute jig with a piece of scrap, a nail and some double stick tape and use a bandsaw. The outer edge won't be as perfect, but in my experience you can hit it with a sanding block and get super clean.

    If you would like more details let me know.
    Edwin

  4. #4
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    Router and circle cutting jig. Thatís how speaker builders cut them, and they cut lots of holes that size for tweeters.

  5. #5
    Join Date
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    Router, either on a trammel or by using a pattern and a cutter than can plunge into the material.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #6
    I use a lathe.
    I don't own one, so I hire a guy that's good at turning.

  7. #7
    I'm with Robert on this. If you don't need an exact size and I'm understanding it's between 2"-4" I'd use a hole saw. Then sand the outer edge. I would imagine a 4" hole saw would cut around a 3 3/4" circle. Using a router and a jig would more than likely get you a cleaner edge.

    Bill

  8. #8
    Hole saw would work, but for future use and variability, I do like the router circle cutting jig. Understand, I want to cut a hole in a board, not just cut out a disc. I'll have to look into circle cutting jigs for routers.

  9. #9
    If what you're interested in is a hole and not a round piece of wood, I'm not sure that a circle cutting jig for a router would be the best solution. With the circle jigs that I'm familiar with, you pin the jig in the center and your router rotates around where you pinned it. The center piece would have to be fastened down some way so it doesn't move as you finish the cut. That could gouge the hole if the block moved.

    I'd make a circle jig and then fasten it to your work, then use a pattern cutting bit in your router to cut the circle. I like pattern cutting bits with bearings that cut flush with the bearing rather than those things you install on the bottom of your router and then have to figure the offset. It's just easier and simpler.

    Mike

    [I cut hand holds on bee hive bodies this way. They're not round but the principle is the same.]
    Last edited by Mike Henderson; 04-17-2019 at 6:20 PM.
    Go into the world and do well. But more importantly, go into the world and do good.

  10. #10
    Quote Originally Posted by Mike Henderson View Post
    If what you're interested in is a hole and not a round piece of wood, I'm not sure that a circle cutting jig for a router would be the best solution. With the circle jigs that I'm familiar with, you pin the jig in the center and your router rotates around where you pinned it. The center piece would have to be fastened down some way so it doesn't move as you finish the cut. That could gouge the hole if the block moved.

    I'd make a circle jig and then fasten it to your work, then use a pattern cutting bit in your router to cut the circle. I like pattern cutting bits with bearings that cut flush with the bearing rather than those things you install on the bottom of your router and then have to figure the offset. It's just easier and simpler.

    Mike

    [I cut hand holds on bee hive bodies this way. They're not round but the principle is the same.]
    Mike, I think you're right!? Maybe what I'm looking for are circle templates, so I can use a flush cutting bit/template bit. Actually, I just thought...maybe I can use a sacrificial board under the keeper board and just not cut through the sacrificial board.
    Last edited by Derek Arita; 04-17-2019 at 7:02 PM.

  11. #11
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    Yes, pattern routing is a nice method to do this and get a clean hole.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
    Derek,
    If you don't mind spending the money for a template here is one from Rockler with multiple hole sizes: https://www.rockler.com/circle-grommet-templates

    If you want the exact size of one of the circles in the template, yes, use a flush trimming bit after cutting out most of the waste with your jigsaw, close to the line. You could also use brass template guide bushings. With different combinations of bushings and straight bits you could accomplish a wide variety of sizes off the same template.

    If this is the type of thing you might do a lot, it would not be hard to make a template just like this for yourself with a router circle cutting jig. I highly recommend a book called Router Magic by Bill Hylton where he demonstrates how to make this template and circle cutting in general.

    Hope this helps

  13. #13
    Join Date
    Jan 2008
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    Colorado
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    Quote Originally Posted by Mike Henderson View Post
    If what you're interested in is a hole and not a round piece of wood, I'm not sure that a circle cutting jig for a router would be the best solution. With the circle jigs that I'm familiar with, you pin the jig in the center and your router rotates around where you pinned it. The center piece would have to be fastened down some way so it doesn't move as you finish the cut. That could gouge the hole if the block moved.
    I've built lots of speakers and subwoofers and I use two sizes of Jasper Jigs to route countersinks and through holes. For through holes I use double sided tape to attach a backer board. It works very well. A CNC would be easier though

  14. #14
    Join Date
    Nov 2010
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    Brooklyn, New York
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    Something like the Jasper 400 is always an option.

    The Model 400 Jasper Circle Guide makes circles from 1 inch to 7 1/2 inches in 1/16 inch increments.The Model 400 Pro is the same as the M400 except that it is made of virtually unbreakable polycarbonate plastic.

    http://jaspertools.com/model-400-circle-guide/

  15. #15
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    I used a router with a circle-cutting jig and double-stick carpet tape underneath to keep the pieces from moving as the center is cut free.

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