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  1. #1
    Join Date
    May 2014
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    Cranleigh Surrey
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    Nylocks and copper grease

    Hi Everyone,

    I'm assembling the suspension on my AK and the instructions recommend using copper grease.

    However, on some components, nylock nuts are required. The question is; is it ok to use copper grease with nylocks?

    I'm concerned that the grease will reduce the friction between the nylon insert and the bolt thread making it less effective at preventing loosening.

    What do you think?

    Neil

  2. #2
    Join Date
    Aug 2004
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    Christchurch, NZ
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    It will be fine! The nylon does not prevent the nut from loosening, it prevents it from falling off and it will still work with a bit of grease on it.
    Cheers

    Myles D-W

  3. #3
    Join Date
    Jan 2002
    Location
    Marlow
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    67
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    1,724
    Hi, Of course nylocks prevent loosening, thats what they are designed to do!

    Jump to search


    Nyloc nut
    A nyloc nut, also referred to as a nylon-insert lock nut, polymer-insert lock nut, or elastic stop nut, is a kind of locknut with a nylon collar insert that resists turning.
    The plastic insert is placed at the end of the nut, with an inner diameter (ID) slightly smaller than the major diameter of the screw. The insert deforms elastically over the threads of the screw, without having threads in turn cut into it. The nylon insert locks the nut by friction against the screw under the applied radial compressive force. Nyloc nuts retain their locking ability up to 250 °F (121 °C).[1]

    Cheers Clive
    On On

  4. #4
    Join Date
    Mar 2014
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    Marham
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    What Myles is saying is that the friction, along the bolt axis, between the male & female threads is what prevents a fastener coming loose, obviously this force can be overcome.

    As soon as the fastener comes away from the mounting surface the thread to thread friction is reduced to almost zero, this is where the nyloc comes in by creating a rotational friction.

    Grease will not affect the axial friction but will, slightly, reduce the rotational friction. So in a high vibration environment where failure is safety critical I would not use grease on a nyloc - But in those conditions I wouldn't used a nyloc I would lock wire.
    AK Gen II - Delivery May '15

  5. #5
    Join Date
    Mar 2007
    Location
    Maldon Essex
    Posts
    235
    Agreed, IF the nylon band in the nut fails to stop it coming loose then how would it stop it falling off? The whole point of a Nyloc is to stop it loosening.

    But in answer to your question, I put mine together with a bit of copper ease and have had no problems, the nyloc will wipe off almost all the grease as you tighten it anyway.

  6. #6
    Join Date
    Aug 2004
    Location
    Christchurch, NZ
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    57
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    2,207
    Quote Originally Posted by Richie View Post
    What Myles is saying is that the friction, along the bolt axis, between the male & female threads is what prevents a fastener coming loose, obviously this force can be overcome.

    As soon as the fastener comes away from the mounting surface the thread to thread friction is reduced to almost zero, this is where the nyloc comes in by creating a rotational friction.

    Grease will not affect the axial friction but will, slightly, reduce the rotational friction. So in a high vibration environment where failure is safety critical I would not use grease on a nyloc - But in those conditions I wouldn't used a nyloc I would lock wire.
    Correct, a tiny band of nylon cannot possible stop a correctly tightened fastener from coming loose; the forces are simply too great. Once loose the rotational forces are relatively small and the nylon stops the nut from coming off completely. From a safety perspective I guess loose fastener is a lot better than no fastener.
    Cheers

    Myles D-W

  7. #7
    Join Date
    Jan 2002
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    Marlow
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    The answer to this question is in the name, it's a LOCKNUT, other wise you would need to place some other kind if locking devise on the fastner such as a Locking washer, or locktight, which you plainly don't have to.

    That's why so many critical items have them.

    Regards Clive
    On On

  8. #8
    Join Date
    Mar 2014
    Location
    Marham
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    41
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    229
    That’s like saying a bulletproof vest is bulletproof!

    Anyway, yes copper grease will reduce friction between the thread and the nylon insert, yes the insert will wipe away the vast majority of the grease, yes a greased nyloc is better than a plain nut.

    With the vibration we’re likely to experience, use copper grease & nylocs, I did!
    AK Gen II - Delivery May '15

  9. #9
    Join Date
    Aug 2011
    Location
    Birmingham
    Posts
    330
    Quote Originally Posted by mylesdw View Post
    It will be fine! The nylon does not prevent the nut from loosening, it prevents it from falling off and it will still work with a bit of grease on it.
    Where is the like button when you need it !

  10. #10
    Join Date
    May 2014
    Location
    Cranleigh Surrey
    Posts
    6
    Many thanks for all the replies guys. I now won't worry too much if I get some grease on my nylocs

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