Are there any IWC pilots watches antimagnetic up to 80,000 A/m?

Thanks a lot Adrian and Heiko for that detailed information!

I hope that my watch copes better than my teeth fillings,when subject to strong magnetic fields.
Kenneth.

Hi Paul, since measurement of the flow of time is the primary function of any watch, that becomes a benchmark to check for any detrimental effects of magnetism. According to DIN 8309, (I quote verbatim) "... a watch must resist exposition to a direct current magnetic field of 4,800 A/m. The watch must keep its accuracy to ± 30 seconds/day as measured before the test in order to be acknowledged as a magnetic resistant watch...."

The effect of magnetism in this regard can be characterized in two ways. The watch may stop when introduced to the magnetic field, but resume its normal functioning when removed from it - this probably happens mostly to quartz watches. The second effect is more damaging. It is the residual effect of the magnetic field on the watch components when they get magnetized such as the hair spring, the spirals of which will start to stick and influence the time keeping capabilities. Other components may get effected as well and compromise the timekeeping ability of the movement.

To avoid these problems, physicists / metallurgists (including those of watch movement manufacturers) research on different materials and alloys to determine the Ferromagnetic, Paramagnetic and Diamagnetic capabilities of each of these materials. Based on the raw materials used the technicians can hypothesize the magnetic properties of a prospective construction - either movement components or the movement enclosure / inner core. In order to test their hypothesis, they probably then create a prototype of the movement / movement enclosure and attach sensitive sensors to or within the prototype and subject it to varying degrees of magnetic flux at a predetermined operating temperature. Based on these tests they are able to determine the safe operating thresholds of the movement / movement enclosure.

Though sophisticated sensors such as those that exist today did not exist during Charles Edouard Guillaume's time, he probably used similar methods to check the effects of magnetism on the alloy he created in 1920s called Enlivar.

This is also probably how it has been determined that with a Beryllium Copper (BeCu) alloy to create "soft iron" inner case enclosures to protect sensitive movements. Beryllium Copper (BeCu) alloy is used because its non-magnetic properties. This core consists of a dial, inner ring and a back cover. The ring and back cover remaining of constant thickness, the thickness of the dial determines the threshold. A BeCu dial of 0.9 mm thickness together with the inner ring and back cover ensures that the movement will remain unaffected by the damaging impacts of a magnetic field upto 1000 gauss or 100μT or 80,000 A/m.

I hope I have answered your question. I am not an expert in this field, and this explanation is based on my understanding on the subject. So others please correct me and help me learn, if I have deviated from an accurate explanation.

Best regards,

Sumit

Hi Michael, thanks for the information! Would you also know if the older doppel 371303 or the newer 2012 doppel 3778, more anti-magnetic than the 3799? I would be much obliged with any information in this regard!

Best Regards,

Sumit

Especially for you Paul :-)

Measuring magnetic fields is quite simple, with a Hall-Sensor:

HALL-SENSOR

If a watch has been magnetised, it begins to run very inaccurate.

The owners have no idea what happened and will often ask an AD.

The AD does not care about magnetism and offers the proposal: It needs a service.

Good for the AD, because a service is quite expensive :-)

But it would be inexpensive simply to demagnetize a watch.

I am sure, a big amount of money is wasted every year, because magnetised watches get a full service instead a simple demagnetization !

That is one reason, why magnetism is still an interesting topic.

Regards

Heiko

As far as I know, ONLY some older Ingenieur have a protection up to 80.000 A/m

The current Ingenieur Automatic Mission Earth Ref. 3236 has 80,000 A/m protection.

Hi Heiko, this just SUPER information!!!! Thank you so much for sharing!! I have saved the picture for my future reference!!!! :-)

Best Regards,

Sumit

This has been a great thread, very informative. I have to light heartedly disagree with the above though. IWC have a great history of innovation, engineering and testing the limit and as an IWC owner I feel we all have an obligation, if not duty to not only know the limits but to test them :)

What is the point of knowing he top speed of a vehicle if you never go there? I once took a MV Agusta F4 312r for a ride - the model number was the advertised top speed so I felt compelled to make sure the bike could do what was advertised and have to say it met its advertised capabilities quite well.
Some people say that life begins at 200 but I can say it really gets going after 300 km/h :D and what better watch to have on whilst doing it than a IWC 3799. I can only say that at a nudge over 310 km/h, the anti magnetic properties of your watch become less concerning but as things start to get blurry and you feel like you are about to tear the time-space continuum I suppose the massive magnetic forces generated by time travel may require a suitably protected time piece.

Cheers,

Ben

Haha true Ben, I agree! That is exactly why I am trying to understand what the limits of my 3799 are! I may never need this, but the the fact that its there kind of adds to the allure of this legendary timepiece.

BTW I wrote to IWC on this. As usual their extremely prompt concierge service replied - The 3799 and the newer 3778 both stand at 24,000 A/m.

I am yet to learn what the anti-magnetic thresholds for the older doppels 3786 and 371303. I will post the data here once I get these numbers...

Best Regards,

Sumit

Hi Heiko, there is an observation I can make from the picture you shared earlier.

Assumption:
The graphical diagram representing the anti-magnetic performance of a soft iron case relates to one that is designed to give a protection upto 80,000 A/m

My Observation:
If we connect two lines from the coordinates, we see that with the shielding, when the field outside is 24,000 A/m, the field inside is ~ 4,500 A/m. Interestingly, this is around anti-magnetic threshold (4,800 A/m) set by DIN 8309 standards for an anti-magnetic movement!! Also its is clear from this graph that when the field outside is 80,000 A/m the field inside the case is ~18,000 A/m, so the movement should have that level of magnetic resistance through the use of specialized escapement parts etc.!!

Best Regards

Sumit

Heiko, that is great information, thank you!

Ben, two thumbs up!

I guess you subscribe to the idea that "too much power is almost enough power". :-)

That and "Its not the speed that kills, its the sudden stop at the end that really messes you up!" :)

I suppose the AM discussion is along the same lines of a lot of discussions with regards to mechanical watches in the modern era - most things are deemed superfluous, like "who really needs 8 days power reserve" or "Who is going to dive that deep" or "Why dont you just use your iPhone??" but at the end of the day we all like to think we may one day use the extra capabilities of our lovely time piece, even if we never do, but we all sleep better at night dreaming of the day that we may dive down deeper than we ever had and glance down at our shiny IWC .

Well said!!