Calling technical WIS/Watchmakers: Milgauss

[yoniman]

Hello WISers and Watchmakers,

Greetings from the long white cloud Aotearoa aka New Zealand.
Question:

Not that it will happen, but IF a date window will be in Milgauss will it affect its capability to withstand the 1,000 gauss magnetism?
Considering magnetic fields can pass trough with or without holes?

Your scientific and physics and watchmaking technical answers shall be appreciated and added to my unused arsenal of WISdomestication.

Photo from rolex.com

Cheers

[HogwldFLTR]

Probably would destroy the Faraday cage.

[SS Oyster]

Depends - with existing movement perhaps. However, if fitted with Syloxi hairspring, likely not.


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[opawlows]

If the Omega Aqua Terra has a date window and is capable of withstanding 15000 gauss don't see why Rolex can't upgrade the Milgauss with a datewheel

[peterpl]

I would 100% buy the milgauss if it had a date on it.

[yoniman]

Hah!
Here's a nugget of WISdom I trawled:

There is no date on the Rolex Milgauss since any cutout on the dial would likely interfere with the operation of the Faraday cage.  

https://www.ablogtowatch.com/rolex-m...-watch-review/

Keep your tech answers coming.
Cheers

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[paulbrl]

Physicist checking in. It's not technically a Faraday cage that protects the movement - a Faraday cage is the mesh-like grid that your microwave oven has to prevent the electromagnetic waves from extending behind the cooking volume.

The Milgauss uses the "old school" method of magnetically shielding the movement using a highly magnetically permeable inner case. This can be made from iron or Mu-metal which is an alloy of nickel and iron. I've played around with designs for a super-magnetically resistant watch and using a ballpark of 60 gauss max on the balance spring I was able to get ~1500 gauss resistance fairly easily. However, make a hole such as for a date window and you can halve this number depending on where you put the date relative to the balance.

The modern Milgauss has the Parachrom balance spring which can probably handle a couple of hundred gauss or more at a guess without being affected - its niobium zirconium alloy is weakly paramagnetic hence the name. An interesting test recently on Hodinkee showed that the Milgauss handled ~4500 gauss with no ill effects which fits this hypothesis. But a date window would reduce this significantly despite being small compared to the size of the watch.

The Syloxi spring would be even better as the diamagnetic silicon would not react to even large magnetic fields. Indeed, this is how Omega have achieved huge magnetic resistance over 15000 gauss. Their movement uses totally non-magnetic materials throughout so it needs no external shielding at all. This allows not only a date window but a full display back!

Hope this answers your questions!

[yoniman]

Hey Paulbrl,

I am in awe of your your reply.
Terrific!

Interestingly, Aqua Terra has a higher capability of anti-magneticism than what Milgauss is claiming and yet has a date window.

Thanks for weighing in!

Cheers




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[yoniman]

Originally Posted by opawlows

If the Omega Aqua Terra has a date window and is capable of withstanding 15000 gauss don't see why Rolex can't upgrade the Milgauss with a datewheel

I would love to see this happen!

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[SearChart]

Originally Posted by yoniman

Hey Paulbrl,

I am in awe of your your reply.
Terrific!

Interestingly, Aqua Terra has a higher capability of anti-magneticism than what Milgauss is claiming and yet has a date window.

Thanks for weighing in!

Cheers




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Omega's movement is entirely made from non magnetic materials, thus achieving a high resistance without a cage.

[Andad]

Originally Posted by SearChart

Omega's movement is entirely made from non magnetic materials, thus achieving a high resistance without a cage.

Great info Paul.

[SearChart]

Originally Posted by directioneng

Great info Paul.

[yoniman]

Originally Posted by SearChart

Omega's movement is entirely made from non magnetic materials, thus achieving a high resistance without a cage.

Whoa!

Thanks, Bas.

Regards

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[SearChart]

No idea what the hole for the date would do in terms of magnetic resistance, it will look rather odd though, having the date deep underneath the shield.

[zengineer]

Half the appeal to me is it not having a date window. I always considered the antimagnetic feature little more than a marketing gimmick anyhow.

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