Unitas 6498 positional error

Thread: Unitas 6498 positional error

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  1. #1
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    Unitas 6498 positional error

    I don't know if I have a problem or not -- but I know I've never experienced such a noticable impact of position on timekeeping.

    I just bought a Swiss Army Ambassador XL with the Unitas 6498. This is my first handwind since I had a Timex as a boy back in the 60s. It's also the first watch I've had with an 18,000 bph beat rate.

    Since it's a new watch, I'm tracking it pretty closely. I like to know how a new watch performs.

    So -- when I am wearing the watch it will lose time at rate of about 15 seconds per day. So far, about three days in, this seems to be pretty consistent.

    Then, when I leave the watch face up over night, it gains time at about the same rate.

    In fact, I wore the watch for about 12 hours yesterday -- over which time it gained about six seconds -- then I put it in my watch box. 12 hours later it had gained exactly six seconds.

    Clearly, you can't ask for a better result over 24 hours, but I've never had a watch that would lose time on the wrist then gain time when stored.

    Any thoughts on what's going on? Would regulation even help or would it just shift things to a net gain or loss if I follow the same wearing pattern? Might it settle down to a more consistent rate after some period of break-in?

    I'm sure many of you in this learned community will have some thoughts as to what's happening. I look forward to reading your responses.

  2. #2
    Member tee530's Avatar
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    Re: Unitas 6498 positional error

    Quote Originally Posted by TwoRotts View Post

    Any thoughts on what's going on? Would regulation even help or would it just shift things to a net gain or loss if I follow the same wearing pattern? Might it settle down to a more consistent rate after some period of break-in?

    .

    Sounds pretty normal to me. To address your specific questions:

    I would guess positional errors are at the root of your observations. If you really want to know your watch, wind it up, put it in one of the six positions (dial up/down, crown up/down/right/left) and leave it there for 24 hours. Note the time gain/loss, then wind it up again and check another position. Then you can see the deviation at each position over a 24 hour period, which includes both the position, and the isochronism (changing state of mainspring wind).

    Impossible to say what is acceptable for positional deviation, since I don't know the origin/quality of this particular Unitas. In general, these movements are pretty accurate, although they are not (with rare exceptions) chronometers.

    Once you know the positional deviation of your watch, and your watch has settled down/broken in (maybe 3 months?) you can evaluate how your
    daily habits affect timekeeping. Walk around a lot? Then the crown down rate will have big effect. Sit at a computer? Then probably dial up and crown left will contribute. You will also know what position to leave your watch at night to offset the gain/loss during the day.

    At this point, you could consider regulation. Note that regulation will just adjust the overall rate, so if your habits are regular enough to, say, gain 10 sec/day, you can ask a watchmaker to slow the rate by this amount. Much more expensive and time-consuming would be asking for adjustment, in which a watchmaker attempts to correct the positional errors by manipulating the balance/hairspring/escapement. I'm not a watchmaker, but I would guess that _all_ watches can be improved by adjustment, but _not_ all watches can be adjusted to very low positional error.

    Not for nothing are movements stamped "Adj 5 pos + isochron" so expensive!

    Good luck.

  3. #3
    Member lysanderxiii's Avatar
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    Re: Unitas 6498 positional error

    The rate over 24 hours will also be affected by the isochronism of the movement.

    A Standard grade ETA 6492 can have up to 40 seconds variation from position, and 30 seconds isochronism.
    familiaritas parit contemptum; raritate admiratione wins.- Lucius Apuleius
    est necessry, accurate ad secundo? - Lysander magna
    iustum est horologium - Obscurus Genius

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  5. #4
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    Re: Unitas 6498 positional error

    Thanks for the prompt responses. I think I will give it some more time and see if the pattern changes. If not, and it if bugs me enough, I may take it to a watchmaker and see about an adjustment and regulation.

    Still happy to get more thoughts from others.

    By the way, I do like the watch quite a bit. The dial is one of the best I've seen -- multiple layers and finished, crisp printing and an overall harmonious design. The execution of the dial is pretty much on par with my Breitling Colt. The lume -- while not in the league of my Orange Monster -- is better than most everything I've got.

    And while I love the design of the hands, there are some fine scratches on the minute hand and, overall, they aren't as well finished as the Breitling or my Seiko Velatura.

    The case design and workmanship are above average and even though the case measures 45 mm, it fits well on my 7 1/8-inch wrist.

    Given that I paid less than half of the MSRP, I think the watch delivers a great return on investment.

  6. #5
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    Re: Unitas 6498 positional error

    It's been my experience that the 6497/8 movements are more positionally sensitive than the 2824s. With those manual wind movements, setting them dial up causes them to run a bit faster and crow up a bit slower. I actually really like this, as I can keep those watches running within a few seconds of perfect time for as long as I care to keep them wound. I have regulated some of my watches if needed to get closer to the 18,000 bph if needed.

  7. #6
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    Re: Unitas 6498 positional error

    Thanks. I'm just not used a watch being slow and fast in the same 24 hours. All of my 2824 variants and my Seiko 7s26s all run consistently fast -- within reasonable limits, but they all gain.

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