Does anyone do pre-cut MDF circles?

Discussion in 'Home Theater Projects' started by Chuck Bogie, Jun 24, 2003.

  1. Chuck Bogie

    Chuck Bogie Second Unit

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    Since we don't have access to a band saw, we're gonna try doing the cuts with a router and a piece of cable.

    How does one do an inside cut (like for the speaker hole?) - seems to me that as you got to the end of the cut, the piece would break, and you'll get deviation...
     
  2. Patrick Sun

    Patrick Sun Moderator
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  3. Chuck Bogie

    Chuck Bogie Second Unit

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    Yeah, the jasper jigs would work for the 15" and 6" holes, but I don't think that the 24"ish end plugs are in its realm of operation...

    Just had a thought - I've got some scrap aluminum - time to do math...
     
  4. John E Janowitz

    John E Janowitz Second Unit

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    If you have a plunge router, make your circle with a few passes. If you're doing 3/4" MDF, take about 3/8" the first pass. On your second pass take about 1/4", leaving about 1/8" of mdf all the way around. Then do your final pass. As you go around pull the router up in a few spots, move it over 1/2", then plunge back down. Basically the idea is to leave 3 or 4 small tabs that are 1/8" thick and about 1/2" wide. They will support the piece so it doesn't drop in. Then you just cut these little tabs out with a utility knife and take out the piece.

    John
     
  5. Brian Bunge

    Brian Bunge Producer

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    If I have to cut a hole when the cabinet is already assembled I don't worry about the piece falling in. Do like John said and make the depth of your final pass really thin. That way, when the center does go to fall in it only breaks off a tiny bit which can usually be knocked down with some sandpaper.

    Oh, and Jasper does have a larger jig that's meant for cutting table tops. I'm tempted to get one, but I figure it would be of limited use since I haven't had to cut anything over 18" yet.
     
  6. Tommy T

    Tommy T Stunt Coordinator

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    Home Depot.

    All the Home Depots in the DFW area that I've seen carry 24" MDF rounds. Not sure if they cut them there or are shipped that way. Give them a call, can't hurt.

    Tommy
     
  7. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Place a piece of scrap that is larger than the diameter of your "through" hole on your work surface. Lay a couple of strips of double-sided carpet tape across the scrap. Peel the paper backing off the tape. Place your MDF on the scrap and cut your through-hole, taking about 1/4" progressively deeper cuts. When you cut through the MDF on your last pass, the scrap inner circle of MDF will be free but neither it nor your new driver bafle will move since they're being held in place with the carpet tape. This method works.
     
  8. Brett DiMichele

    Brett DiMichele Producer

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    I just use my 18 Volt Ryobi Roto Tool with the circle guide
    works great! 3/4" MDF in one pass.
     
  9. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Home Depot sells 24 inch plywood circles, 3/4" thick, I used these double thickness on my Sonotube at each end (4 total, 2 at each end glued to make 1.5". ) Forget the price tho.....
     
  10. NathanH

    NathanH Stunt Coordinator

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    I've seen the pre-cut wood circles at HD and Lowe's as well up to 24". Price was ~$10 or so I think....

    I used a Rotozip with circle cutting attachment for mine. Worked out pretty well, but I would have preferred the more powerful router for a cleaner cut all the way around. Anyways - it was cheaper to use my existing Rotozip than to go buy a router with accessories.

    Nathan
     

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