Please Help Me with 'Standard 1/4"-20 Screws'

Discussion in 'Archived Threads 2001-2004' started by Richard Burzynski, Dec 13, 2001.

  1. Richard Burzynski

    Richard Burzynski Second Unit

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    Here's the skinny.

    I bought new NHT speakers, model SB3. They ae going to be wall mounted. I contacted NHT and they told me I needed a particular mount. I searched the web and got a good price for the mounts. But no screws to attach the mounts to the speakers.

    Back on the phone with NHT. They tell me I need "standard quarter twenty screws", preferrably steel as the sleaves are steel. I asked for a length, they repeated "standard quarter twenty." Fine with me.

    OK, off to my local Home Depot I go. Turns out that a 1/4" (diameter) - 20 (twenty threads per inch) screw(or bolt) comes in MANY lengths: ranging let's say from 1/2" to 4".

    So, me being the screw genius that I am, figure that if there are 20 threads to one inch, they probably meant a one inch long screw. So that's what I bought, a bag of 1" long 1/4"-20's.

    Well, I get home and try them out only to find that they are TOO LONG. The hole is not deep enough for these 1" long screws.

    At this point I feel like a total idiot.

    Some one please help.

    WHAT IS A "STANDARD" QUARTER TWENTY ???

    Thanks.

    Rich B.
     
  2. Wayne A. Pflughaupt

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    Wayne
    Nothing to it, Richard. Just screw in the bolt as far as it will go and mark it. Measure from the mark to find out how long of a bolt you need.
    They called it “standard” because umm, that’s what it is! [​IMG] It’s a standard bolt size. Going up the line, there’s 3/8-16 (or maybe -20, can’t remember), 1/2-16 (I think), and so on. Smaller than 1/4-20 they use a number (gauge perhaps?) to designate the size. The sizes down from 1/4-20 are 12-24, 10-24 and 10-32 (i.e., fine and course thread), 8-32, 6-32 and 4-40.
    As you can see I’m a little rusty on some of the threads-per-inch designations of the larger bolts, but I hope this helps. Maybe someone else will help me out here.
    Happy Holidays,
    Wayne A. Pflughaupt
     
  3. Richard Burzynski

    Richard Burzynski Second Unit

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    Wayne:

    Thanks, sounds easy enough.

    What gets me is that I specifically asked this question of NHT CS. If they recommend a particular mounting bracket for their speakers, you'd figure they would know what screws (length and all) that I would need.

    Rich B.
     

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