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SS5 disk drive screws

Discussion in 'Sun Hardware' started by Michael Moeller, Sep 23, 2011.

  1. Hi, I've got a somewhat peculiar question regarding the type of screws
    the disk drives are attached with to the cradles. Looks like an
    in-between of Torx and crosshead. I've got a whole set of tools which
    seem to fit at first sight but actually they don't. The screws are
    pretty tight and I want to avoid doing any damage. Does somebody know
    what these screws are called? Maybe it simply is a design specific to
    the US.

    Michael Moeller, Sep 23, 2011
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  2. Hmm, I don't remember anything specificly odd about the screws.

    I'd imagine though that its probably a design that would let you use
    either a torx or philips, and not anything super special.

    While I do have alot of odd screw drivers (including a whole set of
    the 5 star torx), I never used anything special for SS5 machines.
    Doug McIntyre, Sep 23, 2011
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  3. Am 09/23/2011 02:55 PM, schrieb Doug McIntyre:
    Yes, looks like kind of a Phillips, but 6 star so to speak. The problem
    is slot width and angle of recess don't go together regarding a
    standard set of tools of this kind. Perhaps someone replaced the
    original parts. Nonstandard screws are without number.

    Michael Moeller, Sep 23, 2011
  4. Michael Moeller

    ChrisQ Guest

    They do vary. Some, perhaps the later ones, use torx, but some use
    standard allen
    / hex type. Both are cap head though. You need good quality tools to get
    the screws
    out, as most of them seem to have blue coloured loctite to stop the
    screws shaking
    out with vibration. They tend to be very tight initially, then
    moderately stiff to
    turn all the way out.

    It;s easy to tell which type you have, as the allen key type have hexagonal
    flat sides, while the torx have hexagonal curvy sides...


    ChrisQ, Sep 23, 2011
  5. Michael Moeller

    DoN. Nichols Guest

    Those screws are designed so either a Torx driver or a straight
    blade can be used -- to make it *easier* to remove, not more difficult.

    And frankly -- I've never seen these screws in something
    assembled by Sun -- but I have seen them in PCs, so someone may have
    changed the screws.

    And the SS5 was one of the computers which used the "Easter egg
    basket" style carrier, which IIRC, used countersunk Phillips head
    screws, not the usual button head screws used by later systems.

    O.K. I just dug up a couple in my stock of spare drives, and
    yes there are four Phillips head countersuck screws going through the
    carrier and into the bottom of the drive.

    There are wells on the sides for button-head screws as an
    alternative, though I have never seen these being used.

    And you can always use new screws if you tear up the head.
    Screws are expendable.

    If you get replacements for the countersunk screws, make sure
    that you get the proper countersink angle. I have seen countersinks at
    60 degrees, 82 degrees, 90 degrees, and 100 degrees. If you get a wider
    countersink than that in the carrier, you will cause it to fail with
    cracks starting from the stress.

    Good Luck,
    DoN. Nichols, Sep 23, 2011
  6. Am 09/24/2011 12:50 AM, schrieb ChrisQ:
    Thanks for your help.
    The screws have a flat head and by what I know by now are no original
    parts. Looks like Torx (hex curvy sides) but the tool must have a
    pointed tip like Phillips to get in. I have to admit I've never seen
    such a thing. On the other hand I normally do 'disassembly' only with
    software :)

    Michael Moeller, Sep 24, 2011
  7. Am 09/24/2011 12:58 AM, schrieb DoN. Nichols:
    Thanks for your input.

    I couldn't find a 'straight blade driver' of appropriate fit.
    So I think the screws might be SAE type.

    I just ordered a set of hex bits of all kind, metric and SAE.
    If I'm lucky the right one will be included. It might be an
    SAE type Torx, although I'm not convinced.

    Michael Moeller, Sep 24, 2011
  8. Michael Moeller

    ChrisQ Guest

    The funny thing is that the thread size hasn't changed, still anc / unc
    thread pitch, not metric, but the torx head variety take a metric
    TT10 x 75 torx screwdriver. Maybe to harmonise in some way to suit
    european sales, but perhaps also there's a inches size torx that fits as
    well, or better.

    It's worth investing a few $ in tools and you don't need many. Stanley
    are a good make for screwdrivers, with part number: 65-340, being the
    torx that fits sun drive sled screws. Sort of related: the old Compaq
    machines could be completely disassembled using a single torx screwdriver
    and they also fitted spare screws in the side of the case. Really well
    engineered and thought out...


    ChrisQ, Sep 24, 2011
  9. Michael Moeller

    DoN. Nichols Guest

    [ ... ]
    At least the straight blade part may well be. I know that
    firearms tend to have screw slots which are unique to the manufacturer,
    and gunsmiths are quite ready to take a grinder to an old screwdriver to
    make one which is a proper fit for the slot.
    There is no separate SAE Torx -- the dimensions are not even
    numbers in either metric or inch units. You might look at the table a
    little way down this web site:


    to see a listing of the dimensions in both systems to confirm this for
    yourself. (They may have been designed to be capable of a specific
    torque (which might be in Imperial or metric units) based on the
    strength of forged steel, and *that* may be where the strange dimensions
    come from.

    The thread on the drives is standardized at a SAE/Imperial
    thread, 6-32 (Number 6 diameter, and 32 threads per inch, which is about
    0.7938mm thread pitch.) The diameter of a #6 screw is 0.138" or
    3.5052mm). So -- you might be able to use a M3.5x0.8 metric screw in
    its place -- if such exists. M3.5x0.6 is the more common thread in that
    size in the metric world.

    As you scroll down, look on the right side (before you get to
    the dimensions table) to see a list of many of the screw styles. (But
    this does not show any of the combination styles, such as the Phillips
    and straight blade (which I've seen more of than Torx and straight,

    Now -- one thing which might be worth checking is where are the
    screws holding the drives to the carriers in your drives. Those which I
    have seen from Sun have the screws going into the bottom of the drive
    (and require countersunk bits), while there are provisions for an
    alternate -- button head screws coming into the side -- two of the three
    holes match up with holes in the drives which I have. The middle one on
    each side does not match up.

    And just another thing just to be sure -- you *are* talking
    about the SparcStation 5 (Which you mentioned in the "Subject: " header,
    not the Ultra-5, (UltraSPARC CPU) which has a totally different mounting
    of the drives and a different carrier. (And the drives for the SS-5 are
    SCA (80-pin D shaped connector), while those for the Ultra-5 are the
    standard IDE drives used on earlier PCs -- 40-pin IDE connector, and
    separate 4-pin power connector.

    Good Luck,
    DoN. Nichols, Sep 25, 2011
  10. Am 09/25/2011 01:59 AM, schrieb DoN. Nichols:
    Yes, S5 and S20 which are the same in this regard. Screws are at the
    bottom. And as I mentioned before I still can't rule out they are no
    original parts.

    Regarding PCs I never needed anything else but a set of metric
    crosshead drivers. I dont know if manufacturers draw distinctions
    regarding screwheads depending on the point of sale and a Sun is not
    a PC. In any case, some of the Sparcs keyboards have a US style layout
    and obviously so do the screwheads.

    Anyway, thanks very much for your help.

    Michael Moeller, Sep 25, 2011
  11. Hi,

    just for the sake of completeness...

    A bit named "T15" fits acceptably. Thanks again for your help.

    Michael Moeller, Oct 5, 2011
  12. Michael Moeller

    DoN. Nichols Guest

    A standard Torx size, then.

    Glad you found it.

    Best of luck,
    DoN. Nichols, Oct 6, 2011
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