Simple Screw/bolts question

Discussion in 'Archived Threads 2001-2004' started by Junior, Oct 11, 2002.

  1. Junior

    Junior Auditioning

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    Hi,
    I am making an order from partsexpress and the last thing I need to start assembling a DIY sub is some bolts or screws for the amp and driver. I am using a ACI 10 inch driver I got half a year or so ago combined with a apex junior amp and I found this link on PE:
    http://www.partsexpress.com/webpage....59&filter=cast
    which basically gives me 2 choices on size, #10-32 or 1/4"-20 CAP. I can't seem to figure out which one I need and I'd prefer not to have to order both and then order again to find out, so can anyone help me? Do you need any more info? Thank you.
    -Junior
     
  2. Dan Wesnor

    Dan Wesnor Second Unit

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    First of all, there are just cap bolts and t-nuts, which you can get at Home Depot, Lowe's, or just about any other hardware store. So you can buy one of each local and try them out if you want.
    Given the problems I have had with T-nuts, I recommend you just get some black screws. T-nuts have no advantages over screws, and they tend to jam, requiring that you drill them out. This ain't easy, and if the drill slips...
    [​IMG]
     
  3. Junior

    Junior Auditioning

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    Hi Dan,

    So you think normal screws might be better huh? Don't you need something on the other end to hold it in place? I guess they are called nuts huh...I'll go take a look locally, thanks and I'll let you know how it goes.

    -Junior
     
  4. Greg.K

    Greg.K Screenwriter

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  5. Michael Hartwig

    Michael Hartwig Stunt Coordinator

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    T-nuts and bolts are the best way to install speakers. If you use wood screws you will only be able to remove and replace the speakers a couple of times before the MDF strips. The T-nuts should be mounted (hammered) to the baffle before the baffle is put into place. Also dry fit the speaker to the baffle to make sure everything fits properly before assembling the baffle to the cabinet.
    I use brass bolts to give a better look; I don't use speaker covers (I like the open look).
     
  6. Dan Wesnor

    Dan Wesnor Second Unit

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    I stopped using T-nuts after the above incident. Every time I used them, at least one per speaker would jam. The other problem is t-nuts working their way loose, in which case it's nearly impossible to even drill it out. I just had to cut an old subwoofer in half to recover the driver for this reason.

    You can remove and reinstall wood screws a few dozen times before they lose their bite. Then you can either fill in the holes with putty, or just rotate the driver a little bit to get fresh wood. Trust me, I've done this many times over the last year.

    If you use wood screws, just make sure to drill a pilot hole first, or the MDF will split.
     
  7. Brian Bunge

    Brian Bunge Producer

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    I'm with Dan on this one. T-nuts are a royal PITA when they work loose. Threaded inserts would be a much better choice as there's no chance of having to destroy a cabinet or driver. Also, concerning wood screws, if the hole gets stripped out, all you have to do is glue in an appropriate sized dowel. Then after the glue has dried, simply re-drill your pilot hole and insert the same screw.

    Brian
     
  8. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    If you're not going to be taking the driver out several times, which I doubt you would, the best way to mount tweeters and mid-woofs is with screws. What kind of screws is important. Use screws with DEEP threads - that's what works with MDF. Everyday wood screws have fairly shallow threads and work okay with tweeters, but I recommend deep thread screws for mid-woofs and woofs. For subwoofer drivers, I use threaded inserts - the kind with split threads that are designed to work in particle board and MDF. I've had lots of boo-boos/mistakes in speaker building, but so far, no screw problems. (Watch it, Brian!).
    McFeely's #6 truss head screws have deep threads:
    http://store.yahoo.com/squaredrive/f...de-plated.html
    And here are the split thread threaded inserts:
    http://store.yahoo.com/squaredrive/f...d-inserts.html
     
  9. Josh.L

    Josh.L Agent

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    can you explain to me how those threaded inserts are used? I cant seem to figure out how they hold anything in place.

    thanks,
    josh
     
  10. Ronnie Ferrell

    Ronnie Ferrell Second Unit

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    Hank-

    Would you use the 8-32 or the 1/4-20 insets for 15" subs? Do you use flanged or no flanged insets?

    If you were using the insets with 3/4" MDF to mount a Tempest sub, what length bolt would you use with the insets?

    If I use Baltic Birch, should I still use insets for the sub? If so, I take it the insets made for MDF will not work, correct?


    Thanks!


    Ronnie Ferrell
     
  11. Michael.Hoffman

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    I do pretty much the same thing Brian does, but instead of using a dowel, I just use toothpicks because they're cheap and easier to find. (Heck, pick up a few when you go out to eat and they're free) Stick in enough toothpicks to fill the hole, let the glue dry and the screws now have something to bite into. This has worked for me when installing drawer slides and I accidentally strip the hole.

    As for threaded inserts, you drill a pilot hole and screw the insert into the wood. Then you can use the appropriate sized bolt, and screw that into the insert without fear of the insert getting stripped. I'm not sure what size insert would be best for mounting subs, but I believe you can use the ones for MDF on plywood also. You can go to the hardware store and check out the different sizes and use what looks best. I would think Baltic Birch Ply would have less of a tendency to strip than MDF would, just my opinion though.
     
  12. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    JOsh, Ronnie, those split-thread threaded inserts are perfect for MDF. Drill the proper size hole and thread them into the MDF from the INSIDE of the baffle. Screw them into the back side baffle surface until they're below the surface a bit. I use the largest size for the largest drivers, like my 15" Tempest. If a driver has few mounting holes, use larger inserts/bolts. For example, I've got a new 8" sub driver that's got 8 mounting holes and even though it's heavy, with that many holes and no plans to remove/replace the driver several times, I'll probably just use #8 black pan head or truss head square drive screws. Bolt length: you can take some measurements and figure that out - long enough to go through driver frame, mounting gasket, into the threaded insert and a little beyond it. Not exact science here - experiment. The split-thread inserts work in MDF and would probably work fine in Baltic Birch too. Go ahead and try them - I've had no threaded insert failures yet. I've used Tee-nuts with no failures, but I sure don't like them. The couple of times I used them, I epoxied them in place (security blanket).
    Have fun [​IMG]
     

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