Accuracy

[Bob_Loblaw]

Anyone concerned enough to post to this forum regarding the accuracy of their mechanical watch, is well advised to look closely into what to expect from a mechanical watch generally, and how their watch, in particular, functions from day to day and over a period of months.

I have several self-winding watches. I currently have 3 that I keep wound exclusively by wearing them. Every morning I note on a spreadsheet how much time they have lost or gained. One has gained 7 seconds in the last month and 0 seconds over the last week.

I have a Timegrapher. Once a month I take readings every 2 minutes for 10 minutes for each of the three values at each position. I then average those for a final result for each of six positions. Values from those positions are then averaged showing values for the watch.

The data from the Timgrapher shows me that one watch will gain 6 s/d in the crown right position and will lose 1 s/d in the crown left position. Leaving this watch in the crown left position at night has resulted in it gaining 0 s/d over the last week. It is a 114270.

Another watch gains a rather consistent 12 s/d as measured daily which closely corresponds to the Rate in each position. Its Amplitude ranges from 232 to 269 and its Beat Error ranges from 0 to 0.3 in various positions. Its values are consistent over ten minutes in each position. I am not a watch professional, but given that this is an Explorer II 16570 I think it may, at the very least, need to be regulated.

I provide this detail merely as an example of what knowledge of the inner workings of a mechanical watch may reveal. The data mentioned here applies only to these two watches. The data is different for each watch and reveals different things about each watch. What I do based on that data is different for each watch. Anyone concerned enough to post to this forum regarding the accuracy of their watch would be well advised to look deeper into how their watch functions. One useful article, there must be others, is "The Concept of Timing” by Walt Odets, https://www.timezone.com/2002/09/16/...-xii-part-2-1/. The experience of the doctor mentioned in this article illustrates the variance we may unknowingly introduce into a watches function.

As controversial as it may be to some here and knowing how a little knowledge can be dangerous, I suggest anyone concerned enough to post to this forum regarding the accuracy of their watch would be well advised to understand how to use a Timegrapher and what its results may indicate.

David Letterman: “Why do you wear two watches?“
A Besotted Peter O’Toole: “Because I don’t want to waste time looking at the wrong wrist."

[tp0821]

Oddly enough every caliber 3135 I've ever had has run slightly slow, about -2/day, which is great of course. Currently I've been wearing a 2019 116610LN for the last 6 months and it's the same. However, resting it face up when off the wrist does seem to help ever so slightly!

[vicsdca]

I stopped caring about accuracy. It's a pointless obsession.

[EEpro]

99.976% accuracy is a turd of a movement so that's really not a useful metric.

[csaltphoto]

I would give it some time. I bought an unworn 5 digit sub that needed a service (It was running about +10, low amplitude, etc. Lube had dried out). After that it varied from about +1.5 to +2.5/day (based on a week). After a few months it settled in to less than +1/day. The service was about 6 months ago.