GMT hand alignment allowable tolerance

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Re: GMT hand alignment allowable tolerance

Post by JAFO »

Thoughts on a GMT movement. Apologies in advance for incorrect part naming.

I presume the drive train/gearing works by connecting the GMT hand to the same drive train as the local hour hand. Also that the hands just cannot slip on the mounting pin.

There must be some special adjustment mechanism for the GMT hand though, as otherwise you wouldn't be able to adjust the GMT hand independently of the local time. I assume the GMT hand can only be moved in steps of an hour, otherwise this problem would be an easy fix without even disassembling the watch. Maybe it's half hours.

So all a service engineer needs to do is set the GMT and local hour hand to the same hour, and any hand alignment issue should be clear, and corrected in a few moments.

What it is, is sloppy work, sloppy quality control, and so on.

I accidentally realised I had a similar issue with my C5 malvern hand winder. (Bought in the last sale, and still hardly worn.) At 6pm, the minute hand has gone past the vertical, but the hour hand hasn't yet reached the vertical. It's not as bad as 5 minutes off, maybe between 2 and 3 minutes off, and there's not a permanent GMT hand reminder of the problem, but it shouldn't happen. Now I know it's there, I can see it at every hour mark, if I look for it.
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Re: GMT hand alignment allowable tolerance

Post by redmonaco »

Anything other than perfect would not be acceptable to me. I do think that a lot of GMT second timezone indicators are far from perfect. I had a couple of Frederique constant GMTs with 2 separate displays. It didn't take more than a couple of adjustments for them to get out of synch...
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Re: GMT hand alignment allowable tolerance

Post by redmonaco »

Thermexman wrote:
Thu Oct 22, 2020 9:42 am
What if...

The watch was fine until it traveled back to you. So, did transit upset it?

You send pics and they say “send it back” because they see the issue.

Transit back upsets the position again and when they look, the issue is less than it was and therefore, now in tolerance with nothing to correct?

So, it may be fine when you get it back?
I think a watch should be able to handle a transit without having its timekeeping affected. Unless they where playing footie with it at the sorting office!!!
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Re: GMT hand alignment allowable tolerance

Post by stefs »

Completely unacceptable to me. It isn't like cw doesn't have previous form when it come to gmt misalignment! It would wind me up every time I looked at it.
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Re: GMT hand alignment allowable tolerance

Post by Blackdog »

A1soknownas wrote:
Wed Oct 21, 2020 10:22 pm

Having the hands aligned is hardly a tolerance issue. They are either aligned or not. It is simply pass or fail.
I really is not so black&white. The 2893 is known to have some alignment issues with the GMT hand.
There's a significant slack in the general time setting mechanism of these movements, you must have noticed that is much more pronounced than, say, a 2824. Also remember that the GMT hand "tracks" during normal timekeeping, but "jumps" when you're setting it independently. There's some slack specific to this hand on top of the general one.

Maybe make it "jump" around the dial once or twice, set the time and see if after a couple of hours it tracks with better alignment.

One thing I do with these is to set the time backwards: I hack, then set the hands to past the right time and back off to the right spot. Maybe this helps.
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Re: GMT hand alignment allowable tolerance

Post by triffidman »

Blackdog wrote:
Fri Oct 23, 2020 1:05 pm
A1soknownas wrote:
Wed Oct 21, 2020 10:22 pm

Having the hands aligned is hardly a tolerance issue. They are either aligned or not. It is simply pass or fail.
I really is not so black&white.

I agree with A1soknowas - it IS black & white. The hands on a watch can only do 1 of 2 things: either point to the right place on the dial, or the wrong place. If they point to the wrong place, that is a "fail". Tolerance doesn't come into it.
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Re: GMT hand alignment allowable tolerance

Post by what-time-is-it »

No point in having a Swiss Made, precision timepiece if it' displays 'ish' time and is within tolerance.
GMT = General Maidenhead Time. :lol:
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Re: GMT hand alignment allowable tolerance

Post by triffidman »

what-time-is-it wrote:
Fri Oct 23, 2020 3:39 pm
No point in having a Swiss Made, precision timepiece if it' displays 'ish' time and is within tolerance.
GMT = General Maidenhead Time. :lol:
Clever!! :thumbup: or even...

GMT = Got Mike's Tolerance meaning that if a CW watch has a GMT hand, it will display time within Mike France's error tolerances, and if you argue otherwise, then tough - as long as Mike says it's within tolerance, it's irrelevant what the customer thinks....he has your money already.
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Re: GMT hand alignment allowable tolerance

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:silent: :silent: :silent: :silent:
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Re: GMT hand alignment allowable tolerance

Post by A1soknownas »

Blackdog wrote:
Fri Oct 23, 2020 1:05 pm
A1soknownas wrote:
Wed Oct 21, 2020 10:22 pm

Having the hands aligned is hardly a tolerance issue. They are either aligned or not. It is simply pass or fail.
I really is not so black&white. The 2893 is known to have some alignment issues with the GMT hand.
There's a significant slack in the general time setting mechanism of these movements, you must have noticed that is much more pronounced than, say, a 2824. Also remember that the GMT hand "tracks" during normal timekeeping, but "jumps" when you're setting it independently. There's some slack specific to this hand on top of the general one.

Maybe make it "jump" around the dial once or twice, set the time and see if after a couple of hours it tracks with better alignment.

One thing I do with these is to set the time backwards: I hack, then set the hands to past the right time and back off to the right spot. Maybe this helps.
Thank you for the info. If it is a common movement characteristic that would be more acceptable. I hope the time setting tips help.

If the OP was told that this is the experience of many others and the same standard for all that would be fine - Or if CW explained the tolerance and why it happens in more detail for this or many other, what often appear to be subjective judgements. It just sometimes seems to be a way of getting rid of a complaint instead of dealing with it.

I just wouldn't want to be within the say 5 out of a hundred people who have to put up with an issue just because there is a tolerance. Especially if this wasn't a problem before and why it was fixed on two other occasions.

It is a good looking watch, especially in my opinion by the colour pop of the GMT hand so it would be a shame if that element isn't right forever.
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Re: GMT hand alignment allowable tolerance

Post by StrappedUp »

I'm not sure how CW install the hands, but I was watching an Oris promotional video a couple of days ago and they had a special jig for the Aquis that sits above the dial which they then "drop" the hands into.
In theory, this means they can't be out of alignment apart from any small machining tolerances.

Other brands I've seen manually position them with a tweezers, then use a press to set them in place.

Unsure as to which is the norm, but I suspect CW use the latter given that we see aligent issues throughout the range.

Getting knocked in transit? I'm not sure I believe that.
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Re: GMT hand alignment allowable tolerance

Post by redmonaco »

Blackdog wrote:
Fri Oct 23, 2020 1:05 pm
A1soknownas wrote:
Wed Oct 21, 2020 10:22 pm

Having the hands aligned is hardly a tolerance issue. They are either aligned or not. It is simply pass or fail.
I really is not so black&white. The 2893 is known to have some alignment issues with the GMT hand.
There's a significant slack in the general time setting mechanism of these movements, you must have noticed that is much more pronounced than, say, a 2824. Also remember that the GMT hand "tracks" during normal timekeeping, but "jumps" when you're setting it independently. There's some slack specific to this hand on top of the general one.

Maybe make it "jump" around the dial once or twice, set the time and see if after a couple of hours it tracks with better alignment.

One thing I do with these is to set the time backwards: I hack, then set the hands to past the right time and back off to the right spot. Maybe this helps.
And another way of looking at it is if there are known issues with this movement then it shouldn't be used for a gmt watch...
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Re: GMT hand alignment allowable tolerance

Post by Henryj »

redmonaco wrote:
Sat Oct 24, 2020 11:43 am
Blackdog wrote:
Fri Oct 23, 2020 1:05 pm
A1soknownas wrote:
Wed Oct 21, 2020 10:22 pm

Having the hands aligned is hardly a tolerance issue. They are either aligned or not. It is simply pass or fail.
I really is not so black&white. The 2893 is known to have some alignment issues with the GMT hand.
There's a significant slack in the general time setting mechanism of these movements, you must have noticed that is much more pronounced than, say, a 2824. Also remember that the GMT hand "tracks" during normal timekeeping, but "jumps" when you're setting it independently. There's some slack specific to this hand on top of the general one.

Maybe make it "jump" around the dial once or twice, set the time and see if after a couple of hours it tracks with better alignment.

One thing I do with these is to set the time backwards: I hack, then set the hands to past the right time and back off to the right spot. Maybe this helps.
And another way of looking at it is if there are known issues with this movement then it shouldn't be used for a gmt watch...
There aren’t a lot of choices out there in the affordable GMT movement range, ETA 2893 and Sellita 330 are about it. Rolex, Omega, Grand Seiko, Tudor, etc. aren’t going to sell movements to third party watch makers. That being said, the OP’s GMT hand alignment looks pretty near OK to me. I’ve owned a bunch of GMT watches over the years and I’d be hard pressed to call this one bad at normal on the wrist viewing range as opposed to close up photography.

It’s a mechanical device, assembled at least partially by hand, so the concept of tolerance is a valid one. Cutting down the allowed tolerances to near visual perfection would require a level of time and hand work unlikely at the CW price point. I’m thinking run each movement for a couple weeks to get all the parts settled in and happy together, then individually set the hands and run for another couple weeks to verify perfect alignment. That’s not gonna happen at CW. Of course, if they did do that, they’d also have a chance to regulate for time keeping and we know that doesn’t happen on the GMT movements.

Edit to add: Taking another look at the OP’s photo, I’m still not bothered by the GMT hand alignment, but the hour hand is noticeably off and that would bug me.
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Re: GMT hand alignment allowable tolerance

Post by iain »

Henryj wrote:
Sat Oct 24, 2020 12:42 pm
.........but the hour hand is noticeably off and that would bug me.
This is a very good point and not something I’d noticed originally. The hour hand and the GMT hand seem to align correctly. You could argue that the GMT hand is therefore perfectly aligned when measured against the hour hand. The actual problem here seems to the that it is the minute hand that is out of alignment.

So the question might be asked, how does CW confirm the GMT hand alignment? If it’s against the hour hand then it probably is within tolerance. Go back and say the minute hand is out and see if you get a different response.
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Re: GMT hand alignment allowable tolerance

Post by Blackdog »

redmonaco wrote:
Sat Oct 24, 2020 11:43 am
And another way of looking at it is if there are known issues with this movement then it shouldn't be used for a gmt watch...
Well.... then we're all out of alternatives...
I don't know of any other readily available GMT movements.

And in fact, the Rolex 3185 also has a significant slack in the time setting. They introduced the 3186 to improve that somewhat, but it is no totally corrected. The Omega 8400/8500 are not GMT but have a jumping hour hand for quick timezone adjustments, and there's significant slack too. I guess the thing of the jumping hand it s not an easy problem to solve.
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