Router bit question

Discussion in 'Home Theater Projects' started by Todd Stout, Jul 14, 2006.

  1. Todd Stout

    Todd Stout Screenwriter

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    Hello all,

    I picked up a router a couple of weeks ago and now I need a few router bits to complete my Adire Kit-281 and Kit-81 speakers.

    I was looking at the MLCS Woodworking site and I was about to order a 3/4" plunge cutting straight bit, a 1/4" spiral upcut, and a 1/4" radius roundover. I can use the 3/4" plunge cutting straight bit to create the driver recess for the 8" woofers but I'm not sure if I can use it for the tweeter recess. The hole for the tweeter is only 2" in diameter so I'm wondering if I might need a rabbeting bit of some sort for that. What would you guys suggest for the tweeter recess?

    Thank you.
     
  2. Joey Skinner

    Joey Skinner Second Unit

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    If you have a circle jig, cut the recess first then make hole for the tweeter. If the 3/4" plunge cutting straight bit is too big for this use a 1/2" or 1/4" and make multiple passes. If you are going to veneer the cabinets you might want to use a 1/2" roundover.
     
  3. Mattak

    Mattak Stunt Coordinator

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    ...and don't recess holes until you've veneered
     
  4. Todd Stout

    Todd Stout Screenwriter

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    I don't think I'll veneer the cabinets. I'll more than likely paint them with some sort of textured black finish (such as the Duplicolor bedliner paint). If I do end up veneering the cabinets, I think I'll still end up painting the front baffles black.

    I don't have a circle jig yet. I've been told a few times on various message boards that it's pretty easy to make one so I'm going to attempt to do that with some press board (it might actually be thin MDF) that I have to build the Kit-81 crossovers on. Can I still use the plunge cutting straight bit to make the recesses for the tweeter with a hole that is that small in diameter?

    I'd like to make some grills for each speaker so I figured a 1/4" roundover would be okay. Maybe I should rethink that.
     
  5. Mattak

    Mattak Stunt Coordinator

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    I've never used anything but straight cut bits and have been fine. Yes, you should be able to make just about as small of a hole using a jig as you'd like. The only problem I ever have, and it's more just a minor inconvenience, is when the radius of my hole is the same as the radius of my router bit-to-router housing and I have to find a spot where there's a recess of metal in the housing to put my hole in my jig for the guide nail/pin. I just use a piece of quality 1/4" plywood or 1/4" plexiglass for my jig. They're so easy to make that I've probably made about 4 since they inevitably get lost with other scrap wood [​IMG]

    Just get your piece of wood or whatever for your jig, make the mounting holes and mount it on with your 1/4" straight cut bit already in, then plunge the bit through the jig and it's pretty much all set. Measure from the cutting edge to the outside straight to where you want to drill the hole for your center hole in the jig. I always use a compass to stencil out the exact circle of the driver recess so that I can be sure the bit lines up perfectly when I set the jig down over the center pin (for a pin I just use a drywall nail with the head clipped off). Set the depth accurately and do a pass at the outermost of the recess, then drill another hole to bring the 1/4" bit inward and repeat as much as necessary to make as wide of a recess as you need for the speaker face, then set it up to do the actual speaker cutout (remove/increase the depth guide) and make a few passes until you're all the way through, being careful as you get close to going all the way through as to not jar the router once you've gone through completely.
     
  6. Jeremy Schulz

    Jeremy Schulz Auditioning

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    For this application the spiral upcut is better. It "pulls" the saw dust up and out of the circle you are cutting. But either one will work fine. I have used both type of bits routing out circles. The 1/4 in. is the better choice and is a more versitile bit.
     
  7. ChrisBee

    ChrisBee Stunt Coordinator

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    If you ever get round to cutting holes for larger drivers then you can easily modify the router straight-cut fence without ever needing to buy a radius jig.

    I replaced the fence itself with a piece of scrap 1.5" x 1.5" x 1/8" light metal angle about 6" long. Which I fixed to the ends of the fence rods with the original screws and lock washers.

    I drilled the holes for the fence rods in the angle upright after marking up carefully with the rods reversed and locked in the router body. Both the angle section and router were placed on a flat surface for marking out the fence rod holes.

    Then I made a small centre hole for a tightly-fitting, small (hard) masonry nail. To act as a long-lived easily-removeable centre point in the other side of the angle. The nail was tapped through the hole with a small hammer to ensure it was fixed at the centre without risk of coming loose. Pincers easily remove the nail centre pin after the cut.

    It worked a treat for 4 x 15" drivers in 2 layers of 3/4" exterior grade, multi-plywood at no expense except for a few minutes work drilling the angle section to fit the fence rods.

    I made trial cuts of hairsbreadth depth using a 1/4" cutter to ensure the holes were exactly the correct diameter before going deeper to eventually pierce the material.

    Cutting movement around the circle should be kept slow to avoid breaking the cutter or jamming the cut with solid, hardpacked sawdust. This is where a spiral upcut bit would have helped. I had to keep stopping to remove the packed sawdust!
     
  8. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Hi, I've been using MLCS as my bit source for years. You're plan is good.
    For recess and through-hole ease and precision, I highly recommend the Jasper circle jigs. Parts Express sells them.
     
  9. Todd Stout

    Todd Stout Screenwriter

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    I ended up ordering both a 1/2" and a 3/4" plunge cutting straight bit, a 1/4" spiral upcut bit, and a 1/4" round over bit. I held off on ordering any sort of rabbeting bit in hopes that I can figure out how to create the recess for my tweeter with one of the plunge cutting straight bits.

    The tweeter requires a 2" hole so I may end up using a hole saw or a forstner bit to make the actual cut out. I am guessing that I can still use a plunge cutting straight bit to make the recess before I make the hole.

    I thought about ordering a Jasper Jig but I don't think that they fit my cheapie Firestorm (Black & Decker) router.
     
  10. Jeremy Schulz

    Jeremy Schulz Auditioning

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    According to jasper's website http://jaspertools.com/ they fit Black and Decker models RP 200, SS1000 RP. So it may work.
     
  11. Phil Olson

    Phil Olson Stunt Coordinator

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    I'd second the Jasper jig. They are easy to use and ready to go for just about and hole size. I also second the up cut spiral. The small straight bits tend to clog and bind, getting very hot, while the upcuts expel the dust quite nicely.

    Do the 1/2" straight bit for the surround then the 1/4" up cut for the hole.
     
  12. Todd Stout

    Todd Stout Screenwriter

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    I emailed Jasper Audio last weekend and asked if the Jasper Jig would fit my Firestorm router. Bill Jasper replied that he thought it would and that they'd guarantee it would fit. I ordered one yesterday so I guess I'll find out for myself if it fits.

    I was going to make my own jig but this looks like an easier way to make my driver cut outs.
     
  13. Todd Stout

    Todd Stout Screenwriter

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    Last weekend I was attempting to mount my Jasper Jig to my router and was only able to get 2 of the baseplate mounting holes to align. Is that enough to safely use the jig on my router? I emailed Jasper Audio about this almost a week ago but I still haven't received a response.
     
  14. Greg_R

    Greg_R Screenwriter

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    2 screws is enough to keep the router from moving in relation to the jig. However, are you sure that the router is centered? As you are aware, the Jasper jig has a lot of mounting holes for different brands of routers. IIRC, there is an instruction sheet with the hole locations labeled for each brand of router...
     
  15. Todd Stout

    Todd Stout Screenwriter

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    I was using that center pin in the collet to make sure the jig was centered as per the instructions on the package. I rotated the jig around a few times and was only able to get two holes to align properly. I'll have to give it another shot this weekend just to be certain.
     

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