Calibration Variance

[pharmguy64 0]

Is there a rule of thumb as to what is considered an acceptable +/- s/d variance rate on the QC calibration photos?

 

For example, is +9 s/d or +10 s/d acceptable or considered to much when purchasing the Swiss eta option?

 

Thanks in advance!

[black263 228]

Is there a rule of thumb as to what is considered an acceptable +/- s/d variance rate on the QC calibration photos?

 

For example, is +9 s/d or +10 s/d acceptable or considered to much when purchasing the Swiss eta option?

 

Thanks in advance!

Wouldn't touch the Swiss ETA option with a bargepole. Read the new member info.

[pharmguy64 0]

Point well taken. But is there a variance in the s/d that is considered too much? Regardless of the movement...

[gavmeister 1]

I'd say the rule of thumb is that a variance of 15 seconds is acceptable and no more than a 1 ms beat error.

I did read this somewhere myself, but can't remember where. I have followed this and not had any issues.

[pharmguy64 0]

Gavmeister,

 

Appreciate your insight and response.

 

Thank you!

[gavmeister 1]

Gavmeister,

 

Appreciate your insight and response.

 

Thank you!

If I can add one more thing...

 

Be mindful that the variance (time gained / time lost) can change depending on the position the watch is placed in on the timegrapher stand.

 

Other things to consider include the Amplitude which is the measure of the amount of rotation in the swing of the balance wheel, in either direction.

Amplitude is higher when a watch is lying flat and usually falls when the watch is in a vertical position, due to the increase in friction. If the watch is not fully charged then Amplitude can also fall as the watch winds down and the mainspring delivers less power to the chain.

Amplitude is a good indicator of the movements health and if is too high or too low, or that changes too much in different positions, can indicate a problem with the movement. Rule of thumb here based on the Amplitude where Amplitude measured

• great : 270-310
  
• acceptable : 250-270
  

[pharmguy64 0]

Gavmeister,

 

Really great information and very helpful. Exactly what I was looking for!

 

Thank you!

[black263 228]

I pay little attention to the timegrapher readings, although I do have one. My aim is to have a "real life" of between 0 and +10 seconds per day, as I use it. So what I do is wear the watch normally for a couple of days, including leaving it face up overnight on the bedside table. This gives me a "real life" accuracy. If it's within my limits, that's fine. If not, I take the back off and put it on the timegrapher, face down so I have access to the movement. Let's assume that in real life it is running 5 secs a day slow. I will look at whatever reading the timegrapher says, and adjust it to an extra 10 seconds, (to go from 5 secs slow to gaining 5 secs a day, the middle of my target). I then put the back on and give it real life testing. I do this until I get consistent real life accuracy within my limits.

 

I go for running fast for one main reason. If it runs slow, it's a bit of a chore to set it. Wait until the second hand reaches 12, hack it, move the time forward. Wait for the accurate time to match and set it going again. If it's running fast, then every few days, I hack it, wait until the accurate time catches up, and set it going again. Job done.

 

As I said, i'm not interested in the precise timegrapher reading. I simply use that as a starting point to increase or decrease by the appropriate amount.

[gavmeister 1]

I pay little attention to the timegrapher readings, although I do have one. My aim is to have a "real life" of between 0 and +10 seconds per day, as I use it. So what I do is wear the watch normally for a couple of days, including leaving it face up overnight on the bedside table. This gives me a "real life" accuracy. If it's within my limits, that's fine. If not, I take the back off and put it on the timegrapher, face down so I have access to the movement. Let's assume that in real life it is running 5 secs a day slow. I will look at whatever reading the timegrapher says, and adjust it to an extra 10 seconds, (to go from 5 secs slow to gaining 5 secs a day, the middle of my target). I then put the back on and give it real life testing. I do this until I get consistent real life accuracy within my limits.

This is an important point you raise here. We all live lives at different pace so there are likely to be variances on how I wear a watch to how you do and the time lost or gained.

 

In practice I will do something very similar to you Black263. I wear the watch for several days (usually three) and track how much time was lost or gained over that period. If for example I gained 60 seconds over three days I'll take the measurement as being 20 seconds per day fast. Onto the timegrapher, and whatever 'average reading' it gives me (say 30 seconds fast), I will simply slow that reading down by 20 seconds, hence I'll be aiming for 10 seconds on the timegrapher.

[markeym3 2]

Yeah i reckon 10 sec's per day is very good for normal wear as described above ,,, you can try and get it better and in some cases it is possible but really you are only doing this for shits and giggles.

[GenTLe 1,490]

Having a timegrapher myself, I am mainly interested in the amplitude when buying a watch. Very often they got out of regulation during the shipment so in any case I re-tune them when they arrive as a part of the "pre-use treatments".

 

[gavmeister 1]

or you could just do it the Rolex way....

 

[Grepp 0]

To check real life accuracy I use the Android app WatchCheck. Very easy to use, recommend it!

[RussP 22,106]

or you could just do it the Rolex way....

 

 

 

Gold !!!

[trailboss99 994]

To check get a very approximate idea of real life accuracy I use the Android app WatchCheck. Very easy to use, recommend it!

Fixed

 

 

There is a reason a timegrapgher cost a couple of hundred for a cheapie.

[Grepp 0]

To check get a very approximate idea of real life accuracy I use the Android app WatchCheck. Very easy to use, recommend it!

Fixed

 

 

There is a reason a timegrapgher cost a couple of hundred for a cheapie.

 

 

Well, not really fixed i think. The app isn't a "phone timegrapher" but a app to log the accuracy of the watch. You will register the accuracy of your watch over time. By doing that you will get a exact historic overview to check if your watch is loosing or gaining seconds the way you are using it. Depending on how often you log you can also see if its consistent.