I think the spec is 4 seconds a day. It is an IWC-modified ETA7750.
Currently, fresh from an IWC full service, I am seeing 7-8 secs a day.
The watch had been to another "trade" watchmaker previously and he got it
within 1 second a day, so clearly this is possible. He said he was Omega
authorised, but ultimately he was unable to fix another highly intermittent
fault with it.
Yesterday, I had the great privilege to attend a tour through IWC's
manufacture sites. During this, our guide said, that the IWC-standard for
accuracy was +0 until +7 seconds within 24 hours. An IWC should never be slow.
I think, a new watch and maybe also a freshly serviced one needs to run in and
then becomes even more accurate. Although 7 seconds within a day with 86'400
seconds is stunning for a mechanical timepiece. And for me, that's absolutely
enough. I didn't buy my IWCs for knowing the time to the last second. If I
need to know this, I look at my mobile.
Philipp
Would one expect the error to change over time? If so, I will leave it for a
bit and see what happens.
I don't exactly agree about not using it to know the time accurately, because
the previous watchmaker had no apparent issue getting it within 1 second a
day. I am sure some 18th century naval clock which loses a minute a day will
be even more beautiful :)
On another occassion, a different watch (an ETA7750 Fortis) was running 20
secs a day slow and when I took it to one watchmaker he said the spec is 20
secs so it would be unprofessional for him to adjust it because it meets the
spec! I wonder if there is a bit of this happening here?
A data point: the 7-8 secs fast has come down to 4-5 secs. Is that normal?
Looks like this is another dead forum :)
Not neccessarily a dead forum: you will see from one of the replies above
that +0 - +7sec is within specifications for IWC. So yours now obviously is.
Update: the watch ended up running 8 secs/day too fast so given that it had a
2 year warranty after that IWC repair, I sent it back to them. It came back a
few weeks (!) later and it is now running 5 secs/day fast :)
Looks like you answered your question in your first post!
Accuracy can also be influenced by the position you put your watch in when you
take it off at night. You can experiment a bit with this to find the position
that compenstates the gains and losses you acquire during day time.
Kind regards,
Clemens
I was aware (hence things like the tourbillon movement which takes out some of
these errors) but this watch is never taken off.
The reason I think IWC are intentionally not trying to get the error as low as
possible is because at one time in the past a low cost watchmaker easily
achieved 1 second per day and it stayed that way. Well, except for the
intermittent fault with 3-4 secs per minute :)