Reply With QuoteWhat's the laptop?
Working from home has forced me to use a laptop instead of a keyboard attached to a laptop like how I would work in the office.
Recently I did a magnetism check on all my watches (using a compass) and was shocked to find that virtually all my watches had some magnetism in them, including a Smiths PRS29A with a full antimagnetic cage, a Rolex Sub (2010) and a Tudor Black Bay GMT (with silicon).
I have asked on other forums about what these antimagnetic hairsprings mean to a watch that supposedly 'isn't' antimagnetic (like the Rolexes) compared with the Omegas that are antimagnetic 15000gauss, and didn't really get an answer. But now I have an answer.
The reason why Rolexes aren't "antimagnetic" like Omega, is because brass (among other materials) are influenced by magnetic fields, but do not retain the magnetic field once the magnetic field is removed. However, since they are influenced by magnetic fields, the fields would influence the timing such that it would not meet the definition of "antimagnetic", even if the hairspring itself is not affected.
Now onto the magnetized Rolex: the compass needle moved ever so slightly when the Rolex was near, and the timing was +2s with a beat error of 0.2ms. After I degaussed the watch, the timing was +0s with a beat error of 0.0ms. There you go! Something tiny was magnetized and it was enough to slightly change the timing. I don't know what the part might have been, maybe someone can hazard a guess?
On the Smiths, they were super super tough to degauss, leading to hours of frustration. Finally I decided to remove the caseback and by doing that they were degaussed in a few minutes. Still: being able to punch through an antimagnetic cage, obviously these laptops have a very strong magnetic field!
What's the laptop?
I have 4 laptops: ROG Strix, MSI Stealth, Dell and HP. ALL of them have strong magnetic fields, I tested all of them. Magnetism is a pandemic. I am now wearing a quartz watch because I don't trust any mechanical watch short of a METAS certified watch around a laptop.Originally Posted by chrisparker
Question for the OP: what are you using to measure rate and beat error?
In my experience a magnetised watch deviates by more than 2 secs/day, If it was magnetised I’d expect to see a bigger change.
I’m never convinced by the ‘compass’ test, the problems arise when the hairspring and possibly the pallet fork become magnetised and you won’t see this with a compass.
I’ve had a few examples recently where owners of watches are claiming the watch is running badly according to figures from a phone app which invariably turn out to be rubbish. I wouldn’t trust the ‘ compass’ effect either if its based on phone readings!
Best test to apply is the simple one; time it against a reliable source over several hrs after fully winding, that’ll tell you what it’s really doing.
@OP: how do you know for sure it's the laptops that magnetised your watches? I use laptops all the time and while it came to my mind a few times that they could be a source of magnetisation, I've never observed anything to that effect.
I picked up a dock for my work laptop from eBay for £11.
Allows me to leave everything, including keyboard, mouse, camera, mic and dual monitors plugged in whilst also keeping the laptop distanced from me…. and my watches.
Time to get a Milgauss ;-)
jk
What tool did you use to demagnetise the watches?
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How do you degauss a magnetised watch ?
The cheap demagnetisers do work, I used5 one for a few tears before buying a slightly better one for £35. There’s plenty of info online explaining how they work, it’s a simple procedure. Ideally, the before and after performance should be checked using a timegrapher, I do this routinely when assessing a watch.
A few years ago I did a quick check of my study/ workroom using a silva compass to detect magnetic fields, this was to safeguard against the risk of magnetising watches after working on them. The only sources of magnetism I found were the speakers mounted on brackets in the corners of the room but this only prevailed for a couple of inches. I didn’t check a mobile phone because I didn’t have one at the time. Unfortunately my compass has gone AWOL during the recent house move so I can’t repeat this, when it turns up I’ll do so and check stuff like mobile phones.
One thing I might try is to deliberately magnetise a watch using a magnetic field proven to exist with a compass, but as I’ve no means to measure the strength of magnetic field its not going to be very helpful other than providing yet another piece of anecdotal evidence.
If someone could measure the strength of magnetic fields around devices such as phones, tablets, laptops etc that would be interesting.
Or a Macbook.
I use the camping type compass from Suunto. The test is foolproof: rest the compass on a table, and see if the needle moves when the watch is moved dial up or dial down by rotating or moving side to side across the compass. There's no way that the compass needle would move if the watch was not in fact magnetized!
I use 2 types of degaussers, 1 a cheap amazon degausser which works for most watches, and a professional K&D 300W degausser.
The 3 watches that were "impossible" to degauss, were the 2 Smiths, and a Yema Superman GMT. Finally I decided to remove the casebacks on the Smiths and was able to conclusively degauss them. I did the same with the Yema, and this did not successfully degauss it, and my conclusion is that the bezel spring is magnetized, but I will not remove the bezel to conclusively pinpoint the source. However, it is in my opinion based on the timegrapher results and the very faint movement of the compass, that the movement is not in fact magnetized any more.
All degaussed watches (minus the Yema) no longer move the compass at all, plus they show expected improvements on the timegrapher in beat error, amplitude and accuracy. The reason why the Rolex only improved by 2s/day, is because it has an amagnetic hairspring, therefore the effects of magnetism are significantly reduced, but not totally eliminated. I might also point out that most of the watches only showed deviances of a few seconds. The Smiths was -20s per day, but is now +2s after degaussing. After repeated attempts to degauss the Smiths without removing the caseback, I got the accuracy as good as -6s per day.
Today I want to give an update. Some of the watches that I definitely demagnetized as there was no movement in the compass yesterday, are now magnetized again, even though I am not bringing them near a laptop. I can only conclude that the metal cabinet where the watches are stored is somehow causing this.
I put my magnetism measuring app in there, and there were some weird areas in there that measured 200ish uT, but generally it was around 90uT which is higher than the ambient 61uT that I measure outside the cabinet. Still, this is lower than the 6000uT that watches are generally resistant to. So I ... don't.. get it.
Weirdly, the Smiths is showing the highest amount of reaction from the compass, but the timegrapher results are the same as yesterday. Healthy > 300 degree amplitude, 0.01ms beat error, 0 to +2s rate. So I don't understand what to make of this.
Other data points include the fact that the Seiko divers are not showing any reaction from the compass. So there is definitely something that is magnetized in many of my watches, but not enough to affect timing. I did some random sampling of spring bars (I did it for the Smiths), and the spring bars are not moving the compass.
The next thing I am going to do is to do a test whether one of my watches which is non-magnetized, will get magnetized by using the laptop.
Only way to possibly solve this is to get more data points. So if some of you would be so kind as to do the compass check on your watches and see if the needle moves even a slight bit, I would appreciate it. Thanks.
Last edited by grizzlymambo; 27th May 2021 at 21:35.
Here is a review I found on the Lepsi magnetism app:
Detector of ferrous metal, and maybe magnetized watches.
Firstly, the app works nicely for what it is. But it should be known that the compass chip in the iPhone will, like any compass, be affected by ANY ferrous metal. Whether that ferrous metal object is magnetized or not. So if the app tells you that your mechanical watch is "magnetized", you are more than likely getting attraction to a ferrous part (the strap springbar or clasp are likely culprits). If no strap, then the mainspring or small screws & parts may be enough to pull the compass, even if not magnetized. If you're demagnetizing over & over and still getting a "magnetized" reading, this is why. Perhaps watch the strength level, if it drops, you may have removed some magnetic contamination, but you'll always get "some" reading from clean steel, if present. All similar apps like this work this way, so not a problem, so long as you are aware.
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If this is true, that may be why I am getting a stronger reaction from the compass from the Smiths watch, because the soft iron core is attracting the needle? Don't know. Maybe someone else can see if their watch gets a reaction from the compass?
Do Mac's have anti-magnetic protection?
I have been using Mac's as personal computers for at least a dozen years or so. My work PC is in a doc, so a couple of feet away. Can't say any of my watched have been magnetized lately. Idid have a issue maybe 6 years ago, which I suspected stemmed from my Damasko's ice hardened case, which I understand can be easily magnetized, "infecting" watches I stored right next to it. Always keep my Damasko a few feet away since.
So just an update, it appears that some components of a watch will attract the needle of a compass, because the needle is magnetized and will be attracted to items that can be magnetized. However, there are many watches with these components so small that unless those components are magnetized, it won't move the needle much or at all because they are inside the case and too small.
So here are my conclusions:
1. Buy a professional degausser that doesn't require you to move the watch away from it to degauss - I find some watches extremely difficult and annoying to degauss using the K&D type degausser or the $10 Amazon degausser.
2. Buy an external keyboard for my laptops
3. Don't worry about a watch moving the compass needle a tiny bit, unless the timegrapher shows less than 260 degrees amplitude or high beat error
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