Accuracy explanation

[Ck8]

My IWC Portuguese Chrono has always been accurate and spot on daily with no gains or losses. Then without any reasons it started to loss 3 secs per day for a few months and now it is spot on most days but every now and then it losses about 10 secs in a day, then spot on again.
I always time check from the same source, greenwich meantime. I wear my watch pretty well the same daily, going to work and same routine daily, no sudden active activity that would affect the timing.
So can anyone explain the fluctuation in the accuracy? I thought mechanic watches are quite constant and consistent, either gaining, spot on and losing the same amount daily.

[Airborn]

Originally Posted by Ck8

My IWC Portuguese Chrono has always been accurate and spot on daily with no gains or losses. Then without any reasons it started to loss 3 secs per day for a few months and now it is spot on most days but every now and then it losses about 10 secs in a day, then spot on again.
I always time check from the same source, greenwich meantime. I wear my watch pretty well the same daily, going to work and same routine daily, no sudden active activity that would affect the timing.
So can anyone explain the fluctuation in the accuracy? I thought mechanic watches are quite constant and consistent, either gaining, spot on and losing the same amount daily.

Hi about accuracy that you mentioned with no losses or gains it is not posible because every movement loses from 3 to 15 seconds per day of course it dependence on quality of movement your watch is TOP GRADE movement so it is like chronometre -4,+6 maximum 10sec/day in 5 positions. But Pellaton is adjusted to +/-5. About losing or gaining there is few possibilities:
1. Temperature differences which influence on lubricant in movement.also moisture.
2. Shock resistance in Portugese is not like in Pilot's or Inge so there is possibility of displacement of hairspring from it's centre. Pellaton winding system in Portu is only one part with shock resistant, which is one piece named "S shape bridge", so you maybe drop your watch, what is mostly problem of precise anomaly of loosing.
3. Maybe the worst thing posible that your watch is fake because there are so good copies that only time can prove their authenticy, quality and accuracy, because fast loosing is proof of fake like in one month from 3 or 4 sec up to 7 to 10 sec per day in short period of time what is proof of low quality of movements parts-wheels, hairspring, power wheel...etc..........................
So my suggestion to you is take your watch to watch maker and polarize your hairspring (+,-), because mostly problem in watches accuracy is hairspring power.
I hope that I helped you

[AIKO]

Originally Posted by Ck8

My IWC Portuguese Chrono has always been accurate and spot on daily with no gains or losses. Then without any reasons it started to loss 3 secs per day for a few months and now it is spot on most days but every now and then it losses about 10 secs in a day, then spot on again.
I always time check from the same source, greenwich meantime. I wear my watch pretty well the same daily, going to work and same routine daily, no sudden active activity that would affect the timing.
So can anyone explain the fluctuation in the accuracy? I thought mechanic watches are quite constant and consistent, either gaining, spot on and losing the same amount daily.

The above explaination is very good. How old is your watch? Is it time for service perhaps? A fantastic watch by the way, one of my all-time favorites!

[cody p]

Originally Posted by Airborn

Hi about accuracy that you mentioned with no losses or gains it is not posible because every movement loses from 3 to 15 seconds per day of course it dependence on quality of movement your watch is TOP GRADE movement so it is like chronometre -4,+6 maximum 10sec/day in 5 positions. But Pellaton is adjusted to +/-5. About losing or gaining there is few possibilities:
1. Temperature differences which influence on lubricant in movement.also moisture.
2. Shock resistance in Portugese is not like in Pilot's or Inge so there is possibility of displacement of hairspring from it's centre. Pellaton winding system in Portu is only one part with shock resistant, which is one piece named "S shape bridge", so you maybe drop your watch, what is mostly problem of precise anomaly of loosing.
3. Maybe the worst thing posible that your watch is fake because there are so good copies that only time can prove their authenticy, quality and accuracy, because fast loosing is proof of fake like in one month from 3 or 4 sec up to 7 to 10 sec per day in short period of time what is proof of low quality of movements parts-wheels, hairspring, power wheel...etc..........................
So my suggestion to you is take your watch to watch maker and polarize your hairspring (+,-), because mostly problem in watches accuracy is hairspring power.
I hope that I helped you

what he said.