# Sudden change in accuracy??



## bpjacobs (Apr 13, 2016)

The DA-35 I bought a couple of months ago has been ticking along nicely; +1/day on wrist and +5/day on winder. A couple of days ago, without any memorable knocks or jars, it has suddenly changed to -3/day on wrist and +1/day on winder. It's still very good accuracy and I take off my hat to Damasko for regulating their watches so carefully. However, I am curious as to how this might happen. Any ideas?


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## StufflerMike (Mar 23, 2010)

Instead of answering your question in my own words let us have a look what Seiko does state

https://www.seikowatches.com/support/faq/mechanical.html


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## Happy Acres (Sep 13, 2009)

A new movement settling in perhaps? If you prefer it to be a bit faster a regulation should do it.


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## heb (Feb 24, 2006)

Although not a factor in your case, I found that geographical location has a major effect on mean daily rate. I just spent 8 weeks in New Hampshire where my Speedmaster Professional gained about 6.5 seconds/day. Now back in Georgia, it's back to +5.5 s/d. The difference in altitude is only about 100 feet. I lived in South Dakota many years ago where my Rolex GMT Master gained 6 s/d, everyday, a common trait of Rolex watches. I made regular weekly trips to North Dakota where the watch gained 2 s/d, every time. The altitude in ND was half that of SD.

heb


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## Nokie (Jul 4, 2011)

^^^^^

Interesting.


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## Tom V. (Feb 9, 2006)

Yes, I, too, have noticed difference in accuracy depending on altitude. When I am home in CO vs being at much lower altitude cuts s/d in half at least. Glad to know it's not just me

Tom V.


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## nepatriot (Oct 1, 2010)

heb said:


> Although not a factor in your case, I found that geographical location has a major effect on mean daily rate. I just spent 8 weeks in New Hampshire where my Speedmaster Professional gained about 6.5 seconds/day. Now back in Georgia, it's back to +5.5 s/d. The difference in altitude is only about 100 feet. I lived in South Dakota many years ago where my Rolex GMT Master gained 6 s/d, everyday, a common trait of Rolex watches. I made regular weekly trips to North Dakota where the watch gained 2 s/d, every time. The altitude in ND was half that of SD.
> 
> heb


My automatics will typically run slow (lose time) after traveling by air, especially flights more than a few hours. Another factor on long flights is inactivity: sitting down for 5 - 8 hours in a day can impact the power reserve.


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## mucklechumps (Aug 15, 2009)

nepatriot said:


> My automatics will typically run slow (lose time) after traveling by air, especially flights more than a few hours. Another factor on long flights is inactivity: sitting down for 5 - 8 hours in a day can impact the power reserve.


This is fascinating. I wonder why? I recently purchased a new Damasko DK14 and on my first day of ownership I flew from the USA to Africa and the watch was running very slowly. I sent it in for regulation and the day after I go it back, I flew domestically but on two flights over 3 hours, a
nd the watch ran (and is still running) quite slowly. I know the continued slow rate is not due to inactivity, and I'm talking about -30 seconds per day slow. Maybe it's coincidence but I can't help thinking the flights had an affect on the rate.


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## nepatriot (Oct 1, 2010)

mucklechumps said:


> This is fascinating. I wonder why? I recently purchased a new Damasko DK14 and on my first day of ownership I flew from the USA to Africa and the watch was running very slowly. I sent it in for regulation and the day after I go it back, I flew domestically but on two flights over 3 hours, a
> nd the watch ran (and is still running) quite slowly. I know the continued slow rate is not due to inactivity, and I'm talking about -30 seconds per day slow. Maybe it's coincidence but I can't help thinking the flights had an affect on the rate.


Its from the inactivity of sitting for so many hours, combined with your total level of activity for the day, or the day(s) prior, which determines what the power reserve level is when you started your travel day.

Automatics need quite a bit of activity to get the mainspring fully wound. The average desk jockey, unless they also work out with the watch on, will not fully charge the watch in a typical day. Depending on the particular day, maybe not much at all. So if you have 2 days in a row of low activity, the power reserve may be at the low end. This is compounded over multiple days of low activity; at some point the watch will slow down.

I travel frequently, often weekly. When I'm home, I walk at least 2 miles per day, 30 minutes, with my watch on. Often I can get in 4 miles. When I do that consistently, in other words the main spring is somewhere closer to being fully wound, my DA46, as an example, runs +3 seconds per day. I put it crown up at night, which slows it down. Recently I spend almost 3 weeks at home, just a few day trips spread out. So with that routine, after 3 weeks, the 46 was at +6 seconds ... that's total, after 3 weeks.

Then I left last Tuesday early AM and did 9 hours of travel on 2 flights. The week was traveling to different cities, and in meetings each day, with no time for exercise. Mostly sat in my rear end. Returned Friday at midnight. Each night put the watch face up to speed it up. When I checked my watch Saturday AM, it was -6 seconds.

Got in my usual 4 miles Saturday, then reset the watch, and kept my at-home routine all this week. The watch is +2 seconds.

Over the years I have found this to be typical for automatics I have owned. Not the accuracy, but the pattern. If you do a search you can find some interesting discussions on how much activity is needed to keep an auto fully wound, how a watch behaves when the reserve is low vs. fully wound, as well as how different movements behave.

My take on all that, and from personal experience, is that, unless you have a watch winder: 1). we are the battery that powers the watch, 2). we can be an erratic power source, 3). when tying to gage a watch's accuracy, there's both "potential" and "actual", with the wearer as the variable.

Which leads to 4). to truly assess a watch's accuracy, you need to start with knowledge that the watch's mainspring is fully, or near fully wound; have a consistent power source to keep it there for the duration of the test period; and the test period should be least several days, ideally one week.


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## mucklechumps (Aug 15, 2009)

nepatriot said:


> Its from the inactivity of sitting for so many hours, combined with your total level of activity for the day, or the day(s) prior, which determines what the power reserve level is when you started your travel day.
> 
> Automatics need quite a bit of activity to get the mainspring fully wound. The average desk jockey, unless they also work out with the watch on, will not fully charge the watch in a typical day. Depending on the particular day, maybe not much at all. So if you have 2 days in a row of low activity, the power reserve may be at the low end. This is compounded over multiple days of low activity; at some point the watch will slow down.
> 
> ...


This is good information, but that's not why my watch is slow. The mainspring was fully wound before both trips and I have a very active job. No desk jockey here. I've owned and adjusted many automatic watches over the years and this movement is getting slower and slower every day despite very vigorous activity and face up at night.


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## nepatriot (Oct 1, 2010)

mucklechumps said:


> This is good information, but that's not why my watch is slow. The mainspring was fully wound before both trips and I have a very active job. No desk jockey here. I've owned and adjusted many automatic watches over the years and this movement is getting slower and slower every day despite very vigorous activity and face up at night.


Sorry didn't see your "30 seconds per day" comment. That doesn't sound right. I'd contact your AD; since you're in the US, the must be Watchmann. Excellent service.


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## mucklechumps (Aug 15, 2009)

nepatriot said:


> Sorry didn't see your "30 seconds per day" comment. That doesn't sound right. I'd contact your AD; since you're in the US, the must be Watchmann. Excellent service.


You're right about that! I purchased my Damasko from Greg at Watchmann and I couldn't be happier with the service. I sent the DK14 in once for adjustment because it was running very slowly, and it still is after adjustment. Damasko suggests that I wear the watch for at least 30 days before adjusting again, so I have a few more weeks of wearing before another adjustment. 
I am still curious if anything about flying besides the lack of activity has an impact on a watch movement running slowly. Altitude? Condensation?


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## Chris Stark (Sep 21, 2015)

Maybe it's your timing app and not the watch. Whatever the case it's extremely accurate. Quit timing it and enjoy your Damasko.


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## nepatriot (Oct 1, 2010)

mucklechumps said:


> You're right about that! I purchased my Damasko from Greg at Watchmann and I couldn't be happier with the service. I sent the DK14 in once for adjustment because it was running very slowly, and it still is after adjustment. Damasko suggests that I wear the watch for at least 30 days before adjusting again, so I have a few more weeks of wearing before another adjustment.
> I am still curious if anything about flying besides the lack of activity has an impact on a watch movement running slowly. Altitude? Condensation?


Easy enough to do a search. I've never heard of altitude having an effect. These are rated to 10 ATM's, and cabins are pressurized, so probably no effect. These watches are, I believe, by heritage and design "pilot" watches. Also supports that altitude should not be a factor. Same for condensation, unless there was some moisture inside the case to begin with. Sinn has some watches with a capsule inside that absorbs moisture. Must be a valid reason. But I don't know any dive rated watch that does that.

Gravity can have an impact on movement, and there are very slight variations based on latitude and altitude. But going back to the 10 ATM rating, I'm note sure what kind of change in altitude\latitude is needed to effect the movement.


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