Northbridge Bolt and Nut vs Plastic rivet

Discussion in 'Mac Pro' started by Raunien, Jul 19, 2016.

  1. Raunien macrumors 6502

    Aug 3, 2011
    Hi all,

    I've read a couple of threads on this topic here on the MP forums, but haven't gotten to a conclusion.

    Has anyone tried replacing the plastic rivet with only a bolt and nut? Or is it better to get a replacement plastic rivet with a spring?

  2. ActionableMango macrumors G3


    Sep 21, 2010
    The Northbridge chip gets very hot. I assume the spring is there to deal with thermal expansion, and so I'd worry that a bolt and nut wouldn't "give" properly.

    Granted, that's just an assumption on my part. I don't know why the spring is there.
  3. h9826790 macrumors G5


    Apr 3, 2014
    Hong Kong
    A little zip tie is the easy / cheap fix for it.
  4. Raunien thread starter macrumors 6502

    Aug 3, 2011
    Thanks guys. I wonder if anyone knows why there is actually a spring rather than a nut/bolt
  5. DPUser macrumors 6502a

    Jan 17, 2012
  6. Dr. Stealth, Sep 16, 2017
    Last edited: Sep 16, 2017

    Dr. Stealth macrumors 6502a

    Dr. Stealth

    Sep 14, 2004
    SoCal-Surf City USA
    ActionableMango is correct... The spring's function is actually two-fold...

    1. It allows for a slight bit of critical movement between the heatsink and the Northbridge chip due to "differential" thermal expansion. Basically the heat sink and the Northbridge chip expand and contract with heat at different rates so there has to be something to allow for this movement between them. The spring allows that. A nut and bolt alone would not.

    2. The spring maintains a constant and even pressure between the heatsink and the Northbridge chip even though there is a small amount of movement between them.

    A nut and bolt would be fine as long as you use the existing spring from the factory spring rivet on the bolt and DO NOT compress the spring (when tightening the nut to the bolt) to the point where the spring is fully collapsed. There has to be some give left in the spring. That said a nut and bolt would work just fine if used with the factory spring.

    Springs on heatsinks are standard practice. Your CPU heatsinks are also spring loaded for the exact same reasons.

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5 July 19, 2016