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Security Torx™ Question

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by Throckmorton, Jan 8, 2011.

  1. Jan 8, 2011 #41 of 111
    Rich

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    And we have a winner!!!

    You gotta understand what a chemical and plastics plant environment is like to appreciate this very simple solution. We had resins floating in the air in some buildings that put such a seal on screws that loosening them up in the normal way just wouldn't work. You'd destroy the screw if you tried. No matter how much pressure you exerted toward the screw head. But just slightly tightening the screw, actually loosened them and then you could remove them easily. My brother was working in an auto repair shop and I dropped in one day and he was battling a screw and I showed him how to do it and he couldn't believe it.

    I learned that from an electrician who was in the tank corp in Africa during WWII. The dust in the desert damn near fused screws in place. Don't remember who he learned it from. Never will find out, he passed a few years ago. Good guy.

    It works on nut and bolts too. The thing with us (the electricians) was that we used brass machine screws for just about everything and if you twist a brass machine screw hard enough the whole top of the screw twists off. Then you have to get an easy-out or drill the rest of the screw out and retap the hole.

    Rich
     
  2. Jan 8, 2011 #42 of 111
    Rich

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    See my reply to VOS. Rusted screws are something else. We used mostly brass screws and didn't have that problem. Our other mechanics would always apply a paste like substance called "Easy Off" that would keep their screws or nuts and bolts from rusting or corroding. Corrosion was a constant battle and we used tubs of that stuff. The drawback was that the screws and nuts and bolts loosened up more easily from vibrations. And the whole place vibrated. Cheery place to work!

    Rich
     
  3. Jan 8, 2011 #43 of 111
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    So here's an "east coast" trick that was never heard of out west:
    With a frozen, rusty nut, striking it with a chisel, on the flats [inline with the bolt] will expand the nut so in most cases it will come off the rusty bolt. Since the nut is now larger, it can't [or shouldn't be] reused.
    The west coast version was to chisel/split it off completely.
    You gotta love east coast winters and salting roads. :lol:
     
  4. Jan 8, 2011 #44 of 111
    Rich

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    That's what I used the "impact drivers" for that Mike posted in his reply to my question. Good tool to have around. Hardly ever use them, but they are cheap and work very well. Just takes one shot with a hammer and the nut loosens right up. Good thing to have in a toolbox.

    Rich
     
  5. Jan 8, 2011 #45 of 111
    armophob

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    IMHO I would not suggest using an impact driver on the screws holding your HR20 hard drive.
     
  6. Jan 8, 2011 #46 of 111
    BattleScott

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    It's not possible to "loosen" a screw by "tightening" it, that's an oxymoron. - or wait that was Billy Mays the Oxy-moron.:confused:
     
  7. Jan 8, 2011 #47 of 111
    armophob

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    But you can break corrosion by tightening a screw.
    Sigh
    I can't believe I fell into this conversation, I need a life:nono:
     
  8. Jan 8, 2011 #48 of 111
    Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    Actually it's pretty much standard procedure for non-torqued fasteners. If it's stuck tighting increases tension on the thread and reverses the contact friction and breaks seal (e.g. loctite). I didn't think that's where Rich was going with this though. It's not really a good idea on fasteners that torqued to full strength.

    Mike
     
  9. Jan 8, 2011 #49 of 111
    Rich

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    I got bored. :lol:

    Rich
     
  10. Jan 8, 2011 #50 of 111
    veryoldschool

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    Think you may have missed the point. I'm well aware of impacts, which can also stall, or break the bolt. By stretching the nut by striking the flats [all sometimes] you've expanded the internal threads, thus easing the nut removal.
     
  11. Jan 8, 2011 #51 of 111
    Rich

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    That's exactly where I was going. And that's exactly what happens. The screws don't always get that tight by over-tightening them. When screws sit in place for years they tend to bond (or at least it seems like a bond) with the surrounding metal. Tightening the screw weakens that bond, or as you said seal, and the screw is easily backed out.

    I've always wondered about that. Surely, they must build a safety factor into the torque wrenches, no? I had a nice torque wrench, but I never had to use it and just left it for the next guy when I got promoted. Never had to use one while plying my trade.

    Rich
     
  12. Jan 8, 2011 #52 of 111
    David MacLeod

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    I created a monster....
     
  13. Jan 8, 2011 #53 of 111
    Rich

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    No, I knew what you meant.

    I was talking about breaking loose the bolts on my motorcycle. They got corroded easily. We're only about 30 miles or less from the ocean. As the crow flies. My bike and I spent a lot of time at the beach, too. The impact wrenches I have I got a long time ago, specifically for my bike. Had to use them gently and never broke a bolt.

    Rich
     
  14. Jan 8, 2011 #54 of 111
    Rich

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    Aww, I thought I started it! :lol:

    Rich
     
  15. Jan 8, 2011 #55 of 111
    Mike Bertelson

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    Actually fasteners in industrial applications are torqued by either a specific gasket crush or a torque value that achieves full strength in the fasteners (FED-STD-H28A). In the case of a full strength assembly it actually is torqued to achieve near yield strength. Handbook 28 has all the dimensions and specs for calculating the torque spec.

    Of course none of this applies to DirecTV's receivers. AAMOF, there is a whole different spec for tightening fasteners for electronics...not full strength assemblies. :grin:

    BTW, I used torque wrenches all the time in the Army/Navy. I once torqued the diesel engine main bearing caps to ≈750ft-lbs. The case for the wrench was four feet long and included two handle extentions. :D

    Mike
     
  16. Jan 8, 2011 #56 of 111
    Rich

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    Wonder if anybody makes them that small?

    Rich
     
  17. Jan 8, 2011 #57 of 111
    Mike Bertelson

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    I don't have a clue but I suspect there isn't one that small. :grin:

    Mike
     
  18. Jan 8, 2011 #58 of 111
    mobandit

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    I know...off topic, but I can't resist. I once had to torque a fastener on an application in the Navy that had a spec of around 750 ft-lbs. I remember the torque wrench was HUGE, had a set of reduction gears in it to multiply applied torque...took two of us to use...
     
  19. Jan 8, 2011 #59 of 111
    veryoldschool

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    "And then there is" when a bolt is tightened by the amount of stretch, and not torque. This usually is by degrees after full contact.
     
  20. Jan 8, 2011 #60 of 111
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I haven't found a manual ¼" drive impact, but battery & air are all over.
     

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