Weak magnetic strip vs mechanical watches

[pingpong]

Hi all,

I understand that we should avoid getting mech watches near magnet. How abt those weaker magnetic strip used in protective case for ipad etc? The magnetic strip are used to keep the protective case cover inplace.

Thanks in advance.

Cheers

[Beelzy]

Just don't set your watch down on it......if it is a vintage that is.

[pingpong]

Originally Posted by Beelzy

Just don't set your watch down on it......if it is a vintage that is.

Thank u Beelzy

[Glenn422]

Originally Posted by Beelzy

Just don't set your watch down on it......if it is a vintage that is.

So modern ones are ok?

[fisherman79]

The modern versions use a new balance spring (the blue one). The older versions used a nivarox. Much more older versions didnt even use an antimagnetic spring.
With the blue spring and the nivarox its not a problem to go into weak magnetic fields.

[salty_snack]

The minimum magnetic field that any modern swiss watch can withstand is 4800 A/m which is about 60 gauss or 6000 microtesla. The parachrome bleu balance spring will resist magnetic fields much higher than 60 gauss but much of the rest of the movement can still become magnetized and decrease the accuracy of the watch, albeit to a much lesser extent.

A few examples of magnetic field strength...
iphone 5: max. 45 gauss
ipad 2: max. 50 gauss
refrigerator magnet: max 40 - 60 gauss
Stereo speaker (next to magnet) >150 gauss

Also, the magnetic field decreases exponentially with distance. So while at the surface of an iphone the magnetic field may be 40 or 50 gauss, moving 1 inch away drops it to less than 20 gauss and moving 2 inches away drops it to less than 5 guass.

So, as long as you don't rest your watch up against anything with small magnets you should be fine. Be cautious around large magnets of course.