FYI:Double the Increments of your Jasper Jig

Discussion in 'Home Theater Projects' started by Baldemar Garcia, Mar 4, 2003.

  1. Baldemar Garcia

    Baldemar Garcia Stunt Coordinator

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    For those who may be interested in doubling the steps of your Jasper jigs, or those overly picky people like me who like their woofer cutouts with minimal 'play', Jesada Tools sells a straight router bit that is 15/64" in diameter. Using this will give you the option of decreasing the indicated hole size by 1/32".
     
  2. Ronnie Ferrell

    Ronnie Ferrell Second Unit

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    Just curious... Is anyone else's jasper jig a little off on some of the holes? I have mine mounted to a DW621. 3 1/8" is just shy of 3 3/16" but 4 7/8" is dead on. I am using a CMT 1/4" 2-flute spiral upcut solid carbide bit. It is very precise and dead on 1/4" diameter.

    Anyone else have this issue?



    rf
     
  3. Dan Wesnor

    Dan Wesnor Second Unit

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    You can also vary the size of the pivot hole, but changing the router bit sounds more reliable.

    Here is a handy-dandy spreadsheet for computing proper jig setting for various speaker diameters and pivot hole sizes.

    http://www.knology.net/~wesnor/Rabbet%20Calc.xls
     
  4. Dan Wesnor

    Dan Wesnor Second Unit

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    FYI, while adding the ability to change router bit size to the above spreadsheet, I found an error which has been corrected. If you downloaded it earlier, you need to re-download it.
     
  5. Baldemar Garcia

    Baldemar Garcia Stunt Coordinator

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    I have to correct myself on my previous message regarding the use of the Jasper jig. Doing some of this so-called simple math, I just figured out that my previous 1/32" increment statement is wrong. Using an odd diameter x/64" bit actually gives you 1/64" accuracy, so finding/using an odd diameter x/32" bit would then give the 1/32" accuracy (by accuracy I mean sizing difference). The good news is that the hole will now simply be bigger or smaller by the same difference as the new bit compared to the 1/4" bit. Ex. using a 15/64" bit will yield a circle that is 1/64" smaller than the pivot hole used, using a 1/2" bit will yield a hole that is 1/4" bigger. Hope this helps.
     
  6. Bob K

    Bob K Stunt Coordinator

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    Ronnie,

    In response to your question, I have seen occasional posts, perhaps at Madisound (not sure), by people indicating slight problems with the Jasper Jig holes. However, I must say that mine is perfect. I use a 1/2" bit and make the appropriate adjustment.

    The one time I had a problem, it turned out that one of the screws holding the jig to the router base had come a little loose, so the base of the router was not absolutely parallel to (and therefore the router bit was not absolutely perpendicular to) the baffle surface. Make sure you don't have a screw loose!

    Tempest Construction Pix: http://www.audiocircle.com/circles/m...view_album.php
     
  7. Pete Mazz

    Pete Mazz Supporting Actor

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    Brain Fart.....
     
  8. DarrenK

    DarrenK Extra

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    Regarding the accuracy of the jig, I've seen a couple things that can decrease the precision of your cuts.

    1. The actual jig is not installed perfectly centered onto your router base. This can cause some holes to be too big, others to be too small, and others to be just right. The most recent version of the Jasper comes with a little centering jig that works great.

    2. The drilled hole is not perfectly perpendicular to the surface of your material. Likewise this can cause minor variations from cut to cut.

    3. Your plunge router actually moves a little bit side-to-side as it is raised/lowered and locked. I know I have a Hitachi MV12 where the plunge base moves a little bit sideways relative to the bit when you depress the locking lever. This could potentially cause some holes off to one side to be bigger than others.

    Anyways, I guess my point is that from my experience the actual Jig is dead-on, its usually some of these other variables that are the culprit.

    See ya!

    Darren
     
  9. Hank Frankenberg

    Hank Frankenberg Cinematographer

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