In a previous thread, Ed U. mentioned antimagnetic movements and balance with regard to a certain watch we were discussing in Pitfalls section.

Would someone give an explanation concerning antimagnetic movements and balance? Did certain companies make them? If so, which manufacturers?

Thanks

Stephanie O'Neil
NAWCC Member 143979

These terms relate to a period in the late 1880s and 1890s when electric power was spreading throughout the country, and concerns existed about the effects on watches of magnetic fields from large motors and other electrical equipment, especially direct current equipment, as AC hadn't yet become the standard. The timekeeping of a conventional watch movement with a steel escapement can indeed be thrown off significantly if the escapement becomes magnetized. Some watches had cases that incorporated "antimagnetic" shields, meaning that they supposedly screened the movement from external magnetic fields. 14K gold is itself an excellent electrical conductor, so I wonder exactly what such supposed additional protection really provided. Movements with "nonmagnetic" escapements, on the other hand, substituted alloys of gold, platinum, rhodium and/or palladium for steel in the balance wheels, hairsprings, staffs, roller tables, and pallet frames. It was actually an old idea. Small numbers of marine chronometers were once made with nonmagnetic escapements to prevent "derangement" during polar exploration expeditions.

Waltham and the "Nonmagnetic Watch Co. of America" (which I believe was a Swiss marketing operation) made such watches. Perhaps others did as well. Waltham charged a significant price premium for their nonmagnetic movements, especially in the higher grades. Most such Waltham movements are engraved "nonmagnetic" on the pillar plate near the balance wheel, but not all such Waltham movements.

Clint Geller

Of course the first non magnetic by the Non Magnetic watch co. were made on Fredonia Street (formerly Fuller street but renamed after they bought the Fredonia watch Co and renamed in in Peoria as the Peoria Watch Company) at the Peoria Watch Company Factory.

Jeff Hess

Here is an example of an 1892 model Waltham, grade No.45. It was presented to the foreman of the electrical department of a major mining company in 1900, and from the looks of the case provided many years of service, free from the magnetizing effects of the workplace.

Dr. Geller,

So in essence, antimagnetic watches were of certain alloys to ward off the affects of magnetic fields. Steel was the culprit!

Thanks for the lesson of Anti and Non magnetic watches.

Jeff H.
Thanks for the info.

Jerry T.,
Thanks for the pic. My first pic I'm viewing of a Non-magnetic movement. Are they rare?


Stephanie O'Neil
NAWCC Member 143979

Hi,
An added note....and I don't know if this had anything to do with the development of anti magnetic watches, but after the war (WW2) all EOD ( Explosive ordinace disposal) units were required to use antimagnetic watches to reduce the chance of an accidental detonation caused by stray magnetism. I do special effects for the motion picture industry and some of our pyro works use activation devices that contain odd tripping devices...reed switches and the like. Out of habit I always wear a watch that is anti-magnetic....You can never be too safe!

In the posts before Bill Cobb’s the term anti-magnetic (and non-magnetic) is used to refer to watches designed to not be affected by external magnetic fields. Bill uses the term to refer to watches designed to not project magnetic fields that could affect external objects.

I’ve forgotten my physics 1-A: are these one and the same?

I believe that any metal that is not attracted (or affected) by a magnet cannot be magnetized...ie they are the same. Correct me if I'm wrong.

Yes, Debbie, "antimagnetic" shields were intended to ward off the effects of external magnetic fields.

And no, magnetic field screening is not reversible. While a conducting enclosure will shield something inside from external magnetic fields, the reverse is not true. (Reversibility holds for electric fields, but not magnetic fields.) A magnetic field source inside a conducting cavity will project a magnetic field beyond the confines of the surrounding conductor. To shield a magnetic source from its environment, one would need not just an ordinary conductor, but a Type I superconductor. Type I superconductors exhibit the "Meissner Effect," which means that they expel magnetic fields from their interior.

Clint Geller

If there is some risk in wearing a watch capable of projecting a magnetic field when around certain pyro activation devices,

and if an anti-magnetic watch wouldn’t eliminate that risk,

if I worked where Bill does I’d want to know: are quartz watches inherently free of magnetic fields?

Perhaps I interpreted this incorrectly, but a metal that will not be affected by a magnet should not be capable of inducing a magnetic field. True enough it will pass a field that is produced by a magnetic source, but if a watch were to be produced with metals that cannot be magnetized it should not be able to create a magnetic field either. I was not aware that we were talking about magnetic shielding of a ferrous material which can be magnetized. For instance..and I go to extremes... if you had a mechanism made of aluminum it would not be affected by a magnet....neither would it have the ability to induce a magnetic field into another item. It would NOT, however, stop a magnetized ferrous material close to it from inducing a field into an object on the other side of the aluminum. Perhaps we're talking apples vs oranges here. My bad if we are.

Hi Stu,
To be honest....I don't usually wear a watch at all when I'm doing pyro. I've had small bullet hit squibs go off from a walkman before during an electrical storm in Atlanta when I was on location there. Generally we do not use any firing device that would be affected by a magnet. I have, however, on occasion used a reed switch to activate a firing mechanism and reed switches are directly activated with magnets. It's not an accepted or good practice though... anymore than using hobby type radio control devices to activate firing. It's done on occasion, but again...not often and it's not safe.

"Are quartz watches inherently free of magnetic fields?"

No. Analog quartz watches operate by means of electric "stepper" motors, which have armatures composed of permanent magnets, that rotate 180 degrees every time an electromagnetic coil is energized by the electronic circuit. All analog quartz watches have at least one strong permanent magnet, and at least one fairly strong electo-magnet (and many models have more than one).
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A metal that will not be affected by a magnet should not be capable of inducing a magnetic field.

Not true. All conductors emit electromagnetic fields when current flows through them. As an example, consider the old "coil-type" demagnetizers; those consist only of numerous rounds of copper wire wound in a circle, and yet they produce intense magnetic fields when energized.
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I've had small bullet hit squibs go off from a walkman before during an electrical storm.

It seems likely to me that the electrical storm was the cause of the accidental ignition(s), not the Walkman. I would guess that if the Walkman played any part at all, it was only as an "antenna," which attracted an electrical spike from a nearby lightening bolt. If that's the case, any metallic object would have done the same thing, be it a lamp cord, a coat hanger, or anything else.
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As for "reed switches," those were commonly used in most of the early LED (Light Emitting Diode) wristwatches. In many cases (Pulsar, Time Computer, etc.) the buttons on the case contained small magnets, which when pushed nearer the reed switches inside, caused them to activate certain functions of the watch. Exposing such watches to intense magnetic fields would typically cause all of their buttons to be "pushed" at once, often resulting in a loss of programming.

For what it's worth, some very interesting antimagnetic wristwatches have been produced over the years, including such legendary models as the Rolex "Milgauss," the IWC "Ingenieur," the "Blancpain Fifty Fathoms Milspec," etc. Most incorporate "Faraday Cage" shielding, but a few, such as the Tornek-Rayville models made for the US Navy "SEAL" teams, actually used beryllium components in place of most of the usual steel parts.

===========================

Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

A metal that will not be affected by a magnet should not be capable of inducing a magnetic field. ...(excuse me....I should have added "without some other external field applied to it")

"Not true. All conductors emit electromagnetic fields when current flows through them. As an example, consider the old "coil-type" demagnetizers; those consist only of numerous rounds of copper wire wound in a circle, and yet they produce intense magnetic fields when energized."


We weren't talking about energizing the metal with an electronic field. The field itself would then be the problem not the non ferrous metal. If you attempt to magnetize a non ferrous metal by any means, be it another magnet or a field of any sort and then remove the field or the magnet the non ferrous metal will NOT create a field on it's own. That was my statement.. or at least what I meant. It did not involve any externally applied electrical field. If you were to take your copper winding and remove the power from it you no longer are creating any magnetic field.Also...You speak of a degaussing coil producing a magnetic field....It does not. It does what it says...it DE-magnetizes and if you apply DC to it instead of the AC it requires for demagetizing it does not produce any magnetic field. Only if it is wrapped around a ferrous material will it produce any magnetism. If you put a bar of non ferrous material within the field it will still not act as a magnet. Try wrapping a large coil of copper wire around a bar of aluminum and with DC current applied to it pick up a nail with it.... I don't think so.. I thought the original concept was watches that were made of non magnetic material....the ones that don't have extension cords plugged onto them!lol
A walkman or any radio for that matter has an oscillator in it. I don't know if it would be strong enough to ever set off a squib. I do know that our studio walkie talkies can do it when transmitting, but a receiver's oscillator is obviously much weaker. Perhaps you're right and it was the storm. The antenna would have been the squib itself, however, since it has about 24-36 inches of lead coming out of it and is shunted on the end. This provides quite a nice dipole antenna for any RF signal or electrical field strong enough to set the squib off. It takes less than 1/10th of a volt to fire one although the current needed is a bit higher than what I would think anything like that would produce

Mr. Cobb,

It isn't my intention to be confrontational, and I certainly hope none of my statements below are taken that way, but a few of your statements above appear to be in error. For example, you say:

"......a degaussing coil [does not produce] a magnetic field...... it DE-magnetizes and if you apply DC to it instead of the AC it requires for demagetizing it does not produce any magnetic field. Only if it is wrapped around a ferrous material will it produce any magnetism."

That simply isn't true. As explained by the "World Book" encyclopedia:

"Electromagnets are temporary magnets produced by electric currents. The simplest electromagnets consist of electric current flowing through a cylindrical coil of wire called a solenoid. One end of the solenoid becomes the north pole of the electromagnet, while the other end becomes the south pole. The poles switch position if the direction of the current is reversed. If the current is shut off, the solenoid loses its magnetism. Many electromagnets have a cylinder of soft magnetic material, such as iron, within a coil of wire to strengthen the magnetic field the electromagnet produces. When current passes through the coil, the cylinder becomes strongly magnetized. The cylinder loses its magnetism, however, when the current is shut off. This characteristic of electromagnets makes them useful as switches in electric doorbells and telegraphs."

As suggested above, the magnetic field of a solenoid or degaussing coil alternates in polarity (north becomes south, and vice versa) with the cycling of alternating current (AC), while the polarity remains constant when direct current (DC) is applied. In either event, however, the magnetic field is generated at the instant current begins to flow, regardless of the presence or absence of a ferrous material. If you don't believe it, just bring a compass (or a gyro) near an energized solenoid, and observe the results. A magnetic core will "focus" the magnetic field created by a solenoid, but the magnetic field exists independently, with or without the core.

If you want to magnetize, rather than demagnetize, using AC applied to a coil, just kill the current so that the field to collapses while the object is still inside the coil. Steel items of all manner can be magnetized that way at will, and demagnetized just as easily by slowly removing them from the energized coil before turning off the power (believe me, I do it all the time).

"If you attempt to magnetize a non ferrous metal by any means, be it another magnet or a field of any sort and then remove the field or the magnet the non ferrous metal will NOT create a field on it's own."

Again, that isn't necessarily true. The term "nonferrous" simply means "without iron," and many of the strongest "permanent magnets" known today (such as samarium-cobalt magnets, etc.), contain no iron, and are therefore, nonferrous. On the other hand, pure iron (FE) has virtually NO capacity for retaining magnetism. Steel (particularly nickel steel) will retain magnetism with ease (even accidentally), but not so with pure iron. Again, if you don't believe it, just try to magnetize a cast iron frying pan, or anything else made of pure iron. Believe me, you'll be disappointed; a magnet will stick to iron objects, but the objects won't retain the magnetism once the magnet is removed.

As for magnetic fields in general, ALL metals have some capacity for holding and/or influencing magnetic fields. That's why airport metal detectors work on ALL metallic objects, regardless of whether they're steel, aluminum, gold, or anything else. It's also why a treasure hunters' metal detector will detect copper and silver coins, and not just rusty nails. All metal detectors operate by generating stable magnetic fields, and sounding an alarm when those fields are sufficiently disturbed by the influence of ANY metallic object or mineral.

"I thought the original [subject of this topic] was watches that were made of non magnetic material....."

To the best of my knowledge, no such watches have ever existed. Even super-nonmagnetic models such as the Tornek-Rayville, etc., have a few magnetizable parts. The "nonmagnetic" pocket watches discussed above, however, simply have (palladium) alloy hairsprings and balance wheels, which allow them to keep consistent rates, even when exposed to relatively moderated magnetic fields. Watches with "Faraday Cage" shielding, combined with nonmagnetic balances and hairsprings, can maintain normal rates in fields exceeding 1000 gauss (1 Tesla), but when exposed to extremely intense fields (say 50 Tesla or more), even the most highly shielded and "nonmagnetic" watches will fail.

In short, there really is no such thing as a completely "nonmagnetic" watch.

Finally, as for the "squibs," you noted that they have "quite a nice dipole antenna for any RF signal or electrical field strong enough to set the squib off," which in a nutshell, is the reason portable phones, radio transmitters, and other RF sources have the potential to detonate them. It's simply their electronic circuits' reaction to RF waves emanating from sources in near proximity.

As always, I hope this helps!

===================================

Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

No offense intended or taken Mr Maddox, but this has turned into a Pi@@ing contest that I won't continue. It's not worth the time or the effort. Neither of us will waiver from our positions...yours from your enclyclopedias nor mine from 40 years of using the devices you speak of. As to the RF....yes...I do understand the concept. I have held a 1st class FCC license for radio repair for almost 30 years and spent almost 10 with IBM as a field engineer.
As to the watches....I haven't a clue. I'm well versed in many areas, but you're the stated watch expert...I'm just a novice...that's why I'm here!
Best Regards to you.
Bill

[This message was edited by Bill Cobb on October 29, 2003 at 0:53.]

Gee ... um ... does anyone want to see another Waltham Non-Magnetic movement? This 1888 model 16-size Riverside from 1890 is one of their earliest (note the marking under the balance wheel). I have a reprint of a Waltham booklet, dated January 1890, entitled "Information concerning a few points in the Construction of a Pocket Watch, also an announcement of a safeguard against one of the dangers to which it is exposed", the latter referring to magnetism. It is a printing of a lecture given by by E.A. Marsh. On page 41 it states that the company has been "since about the middle of 1887, constantly engaged in extensive and costly experiments, and with very gratifying success, so that they are able to refer to thousands of their new non-magnetic watches ... " Further discussion in this booklet mentions the metallurgical changes in the balance wheel, hairspring, roller, pallet and fork.

.. for a LOT more info on Non-Magnetic watches (and cases) take a look at the Railroader's Corner in your August and October Bulletins. Ed Ueberall and Kent Singer provide a wealth of information on the topic.

Hi again Mr. Cobb,

Like you, my father earned a First Class FCC Radio Maintainer's License in 1955, and held it through 1985, when as I'm sure you know, all "first" and "second" class licenses were merged into one "general" license. He then held the "general" license until 1995, when as a retiree, he no longer felt the need to maintain it. In any event, want you to know that I do have the appropriate respect for your qualifications.

In general, I've found most information in encyclopedias, such as that quoted above by Brian B. Schwartz, Ph.D., Prof. of Physics, Brooklyn College; Associate Executive Officer, The American Physical Society, and Richard B. Frankel, Ph.D., Prof. of Physics, California Polytechnic, to be relatively accurate. In addition to the opinions of such noted "experts," however, I have a few meager credentials of my own, including a BA from the University of Arkansas, and a certificate of merit from the USAF issued to me a number of years ago for electromagnetic field theory research. I was going to post a scan of that for you, but it hasn't been important to me in so many years now, that I have no idea where it is. If you like, however, I did (accidentally) find a certificate presented to me from the Arkansas Power and Light Company for "Outstanding Contributions to Energy Research," and I'll be more than happy to post a scan of that for you, if you like.

Again, it isn't my intention to argue or to engage in any sort of "contest," but only to attempt to provide the most accurate information possible here for our members and guests. I'm occasionally mistaken myself, and when I am, I sincerely appreciate any additional information that helps me gain a better understanding, and helps straighten out any incorrect information I may have inadvertently passed to others. I feel that the more knowledge one has, the more potential one has, but that potential is lost if one's information isn't accurate. In short, while ignorance may be bliss, it's seldom helpful in any practical way to those who possess it.

If there are any specific errors in any of my replies above, I'd very much appreciate it if you (or anyone else) would call them to my attention so that the accurate information can be conclusively determined and disseminated, in accord with the stated "mission" of our Association. It isn't important to me personally who's right or wrong, the important thing is having accurate information presented for those who might be seeking it. We're all here to learn things, and none of us are well-served if the information we're presented isn't correct.

Oh! Just to let you know that I'm not a self-proclaimed "Watch Repair Expert," that title was "bestowed" upon me some time ago by Lindell Riddle. While I personally think it's a bit overstated, I've never bothered to change it, although I must admit that your comment has me seriously considering it. I'm just a watchmaker, although I will admit that I've done quite a number of other things during my life as well.

My best regards to you as well, and I assure you that no offense has been intended or taken on my part!

Steve Maddox

=======================

PS -- For those interested in such things, one widely accepted definition of "magnetism" is:
The force that electric currents exert on other electric currents.

Hi Steve....Forgive me....My statement about the "watch repair expert" wasn't as a self proclaimed statement...I know for a fact that you are after talking at some great lengths with Lindell and having your expertise come up in the conversations. I'm also aware that your stated facts are correct. My "arguements" if we want to call them that are not about facts as they are written, but more about reality in practice. I very recently had two of my design circuits for computers Microsoft approved "plug and play". It's taken two years to have that happen and the two years were due to theory and practice not always agreeing with each other. A circuit board that I laid out in theory should have been flawless, but in reality when inductive and capacitive reactance came into play the board had to be redesigned to compensate for that. I felt that what we were talking about entered that same area. Two years ago I had the pleasure of working with the largest Tesla coil in the world for several weeks. The builder and owner set it up on a stage and this thing is the most awesome piece of equipment I've ever been around. It will discharge a bolt several hundred feet long, raise the hair on your arm many feet away from it and the smell of ozone after it has fired is like the devil himself were standing next to you! I do know what large fields can do and we're dealing with several MILLION volts here.
I'm sorry....I'm getting off the track here. I also build and sell all rapid fire detonation devices for explosives to be used in the film industry and they've found their way all around the world in the past 15 years. I hand wind all the solenoid coils in these and it gives me a great deal of "hands on" experience with magnetics and the spikes created by collapsing fields. It also exposes me to what outside influences will affect what I build and use. I'm ever aware of these factors simply because if I'm not I'll end up with missing fingers or be dead...or even worse, someone else will be dead. I've worked with and around pyro for 20 years and the films I've been on have included those such as " War Games, Volcano, Godzilla, Lethal Weapon, Galaxy Quest, Inspector Gadget, Erin Brokavich (sp?), Traffic, Time Machine, Numbers, Oceans 11, Solaris, Swat" and many other not so well known films. I pride myself on a perfect, no injury record.
Anyway...I've gotten carried away again. I guess what I've been "debating" is not anything you've said as much as it is that written fact and reality in practice do not always agree with each other. I'm sure you've seen many instances where they don't. That does not mean that the differences cannot be explained with fact...only that appearance and actual experiences do not always agree with what the facts teach us.
Thanks for your replies. I hope we can "chat" in the future. I'm sure I'll have a thousand watch related questions to ask you!
Regards,
Bill

Nice watch Jerry. Hey...as an experiment have you ever taken a magnet to it to see if there was any effect on it? Better yet, would it yank your pocket up against steel posts after you did?lol

Thanks to all who have participated in this thread.

We have learned alot regarding antimagnetic movements in watches.

Thanks again.

Stephanie O'Neil
NAWCC Member 143979

Clint noted that the timekeeping of movements with steel escapements can be thrown off if the escapement becomes magnetized, and so movements with "nonmagnetic" escapements that substituted other alloys for steel were developed to be (as JerryT said) free of the magnetizing effects of the workplace.

The General Railroad Timepiece Standards included a steel escape wheel. Most steels are magnetic. Since non-magnetic movements couldn’t have steel escape wheels would it be correct to conclude that non-magnetic movements didn’t qualify for railroad time service pursuant to the GRTS?

Still trying to make sense of all this!

The primary escapement part affected by magnetism is the balance, and that's presumably the part to which Jerry was referring. If a magnetic field is intense enough, virtually any magnetic part can be affected, but under "ordinary" circumstances, it would only be the balance.

Most magnetism problems in watches result from the "polarization" of the balance spoke arm, and the harmonic disturbances that result in relation to the hairspring. Since the hairspring is essentially a long bar, one end tends to polarize positively, and the other end negatively. In magnetic fields, opposites attract, which means that the positively polarized balance spoke will be attracted to the negatively polarized end of the hairspring, and the negatively charged end will be repelled by it. Of course, as balance amplitude changes due to varying mainspring power and/or varying positional frictions, the timekeeping will become wildly erratic.

If an ordinary watch is strongly magnetized, the hairspring will simply stick to the balance spoke arm, and the watch won't run at all. If the magnetism is less severe, however, the rate will be erratic by varying degrees, depending on the intensity of the magnetism. Watches that still run, but are significantly magnetized, will create a strange and distinctive pattern on a watch timing machine. The ordinary print record which should be in straight lines, will instead be in wavy lines, which may wander either fast or slow, depending on conditions.

Again, for really significant degrees of resistance to magnetic forces, the more nonmagnetic parts that can be incorporated in a watch, the better it will be, but for any "usual" conditions that an average railroad worker might encounter, a watch with only a nonmagnetic balance and spring should be quite sufficient.

=========================

SM

Well, the problem of magnetism isn't one that's gone away in the work place. I'm an industrial videographer of 30 years, and have personally experienced the loss of an LCD wrist watch many years ago when I reached inside a 3/4 U-Matic VCR to clean the heads. When I pulled my arm out of the unit, I was 'fortunate' enough to see the screen of my watch go crazy, flashing literally every screen of the menu before dying, never to come on again. Fortunately it was a cheap watch, but all I can figure is it came close to a magnetic field in the VCR (it is a magnetic media, and has a permanent erase head inside the unit) which nuked the electronics of the watch. I rarely wear a wrist watch when I come to work now. Regards. Mark

NAWCC Member 157508
NAWCC-IHC Member 163

An 1890 Waltham booklet promoting the company’s Non-Magnetic watches (Information Concerning a Few Points in the Construction of a Pocket Watch also An Announcement of a Safeguard Against One of the Dangers to which it is Exposed) boasts (page 41) that: “This, the greatest achievement in modern horology, has been accomplished by substituting for steel as used in the balance, roller, hair-spring, and pallet and fork (which together constitute that portion of the watch designated as escapement), metals or alloys which are non-magnetic.” No mention is made of escape wheels.

Were the escape wheels in Waltham's Non-Magnetic movements made of steel or of non-magnetic material?

If they are steel: doesn’t that refute Waltham’s argument for non-magnetic escapements?

If they’re not steel: how did Waltham's Non-Magnetic movements qualify for railroad service under the GRTS?

It's the second pocket watch that I ever owned.

B

Brian,

What a beautiful watch movement!!!

Phil Dellinger