Magnetic weapons

Ann Feuerbach · 2nd March 2005, 06:39 PM

Thanks Gene for the generous offer!

I will take you up on it as soon as I have time to spend doing research. Right now they would just be used as paper weights, until I finish lecturing this term. I will be looking for ingots and blades to include in the book. Where did you get the ingots from?

Jens Nordlunde · 7th March 2005, 02:49 PM

A small knife I have, in a scabbard together with a katar, is very magnetic, but the katar is not.
The picture to the left shows the tip of the blade, and the one to the right the compass at the base of the blade. The small knife is made in the first quarter of 1600, the katar is newer.

Rivkin · 7th March 2005, 04:02 PM

When magnetic moments are positioned alongside a line (good approximation for thin swords), there are basically two stable configurations - all magnetic moments are oriented along the line, parallel to each other, or they are all perpendicular to the line, and anti-parallel to each other, i.e. +-+-.

What you have most likely shows that you physically have different steels (most likely phases or chemistry) at the tip and for the rest of the blade, so you've these two macrodomains anti-parallel to each other.

Jens Nordlunde · 7th March 2005, 04:28 PM

Rivkin, thank you for your answer. I understand what the words, but I have a feeling, that I don't understand the whole meaning. I understand, that when we have come as far as we have, and want to go further, the language is likely to get more complicated. Is it possible for you to explain it in another way?
Here is a picture of the katar and the little knife.

Rivkin · 8th March 2005, 04:25 AM

In a very approximate manner:

When magnets are dropped into a narrow, long box, they naturally prefer either to align all parallel to each other parallel to the long side of the box, or anti-parallel to each other (with anti-parallel polarities) and perpendicular to the long side of the box. In both cases the magnets will lie parallel to the magnetic field created by other magnets.

So your configuration is most likely due to the case that at the tip you have some anisotropy , most likely due to changes in steel's chemistry or physics (phases).

Just my 2c.

Jens Nordlunde · 8th March 2005, 03:11 PM

Andrew, thank you for making this tread a sticker. Some collectors collect weapons and keep it at that, a lot of others are also interested in the ‘background’ story, how was the ingots made, why did the pattern appear/disappear, why did smiths have difficulties in forging the ingots, why are some of the blade magnetic, things like this line. I think the thread ‘Magnetic weapons’ answers a few of these questions, and hope we can get more questions answered in the future.

Thank you Rivkin, for ‘translating’ you mail for me – I think I now understand what you mean.
The ‘uncomplicated’ subject ‘magnetism’, has proved itself to be anything but uncomplicated, but I find the discussion very interesting, and hope, the other members do too – I for one has learned quite a lot, although I did not understand all the mails.

Jens

Andrew · 8th March 2005, 03:21 PM

Hi Jens. Like many of us, I've been following this thread with interest, if not with complete comprehension.

The technical information contributed by posters like Rivkin and Dr. Feuerbach (and others!) is outstanding. Gene's "field work" has been terrific as well.

Battara · 31st March 2005, 07:20 PM

Hey Jens, what type of knife is that next to the katar and how old is it?

Jens Nordlunde · 1st April 2005, 08:22 AM

Hi Battara,

The katar shown has a funny history. I got it almost thirty years ago, in England I think, and a year or two ago I showed a picture of it to a friend, shortly after he came back with the following story, after having visited a friend of his, who has some books about English cutlers. They agreed that it was hardly an Indian mark on the little knife – but it could be English – so they started to look through the books: The small knife has a cutlers mark in the blade. The mark belonged to John Jencks, 1576-1625. He got his cutlers mark in London 1606-7. He was born in Blackfriars and died in the Tower of London. His mark was a thistle and a dagger.

For further study see: J.F.Hayward: English Cutlery. Victoria & Albert Museum, 1957. Masterpieces of Cutlery and the Art of Eating. Victoria & Albert Museum, 1979.

I forgot the cutlers mark.

7th March 2005, 02:49 PM	#2
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	A small knife I have, in a scabbard together with a katar, is very magnetic, but the katar is not. The picture to the left shows the tip of the blade, and the one to the right the compass at the base of the blade. The small knife is made in the first quarter of 1600, the katar is newer. Attached Images

7th March 2005, 04:28 PM	#4
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Rivkin, thank you for your answer. I understand what the words, but I have a feeling, that I don't understand the whole meaning. I understand, that when we have come as far as we have, and want to go further, the language is likely to get more complicated. Is it possible for you to explain it in another way? Here is a picture of the katar and the little knife. Attached Images

1st April 2005, 08:22 AM	#9
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Hi Battara, The katar shown has a funny history. I got it almost thirty years ago, in England I think, and a year or two ago I showed a picture of it to a friend, shortly after he came back with the following story, after having visited a friend of his, who has some books about English cutlers. They agreed that it was hardly an Indian mark on the little knife – but it could be English – so they started to look through the books: The small knife has a cutlers mark in the blade. The mark belonged to John Jencks, 1576-1625. He got his cutlers mark in London 1606-7. He was born in Blackfriars and died in the Tower of London. His mark was a thistle and a dagger. For further study see: J.F.Hayward: English Cutlery. Victoria & Albert Museum, 1957. Masterpieces of Cutlery and the Art of Eating. Victoria & Albert Museum, 1979. I forgot the cutlers mark. Attached Images Last edited by Jens Nordlunde; 1st April 2005 at 12:26 PM.

2nd March 2005, 06:39 PM	#1
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	Thanks Gene for the generous offer! I will take you up on it as soon as I have time to spend doing research. Right now they would just be used as paper weights, until I finish lecturing this term. I will be looking for ingots and blades to include in the book. Where did you get the ingots from?

7th March 2005, 04:02 PM	#3
Rivkin Member Join Date: Dec 2004 Posts: 655	When magnetic moments are positioned alongside a line (good approximation for thin swords), there are basically two stable configurations - all magnetic moments are oriented along the line, parallel to each other, or they are all perpendicular to the line, and anti-parallel to each other, i.e. +-+-. What you have most likely shows that you physically have different steels (most likely phases or chemistry) at the tip and for the rest of the blade, so you've these two macrodomains anti-parallel to each other.

8th March 2005, 04:25 AM	#5
Rivkin Member Join Date: Dec 2004 Posts: 655	In a very approximate manner: When magnets are dropped into a narrow, long box, they naturally prefer either to align all parallel to each other parallel to the long side of the box, or anti-parallel to each other (with anti-parallel polarities) and perpendicular to the long side of the box. In both cases the magnets will lie parallel to the magnetic field created by other magnets. So your configuration is most likely due to the case that at the tip you have some anisotropy , most likely due to changes in steel's chemistry or physics (phases). Just my 2c.

8th March 2005, 03:11 PM	#6
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Andrew, thank you for making this tread a sticker. Some collectors collect weapons and keep it at that, a lot of others are also interested in the ‘background’ story, how was the ingots made, why did the pattern appear/disappear, why did smiths have difficulties in forging the ingots, why are some of the blade magnetic, things like this line. I think the thread ‘Magnetic weapons’ answers a few of these questions, and hope we can get more questions answered in the future. Thank you Rivkin, for ‘translating’ you mail for me – I think I now understand what you mean. The ‘uncomplicated’ subject ‘magnetism’, has proved itself to be anything but uncomplicated, but I find the discussion very interesting, and hope, the other members do too – I for one has learned quite a lot, although I did not understand all the mails. Jens

8th March 2005, 03:21 PM	#7
Andrew Member Join Date: Nov 2004 Location: USA Posts: 1,725	Hi Jens. Like many of us, I've been following this thread with interest, if not with complete comprehension. The technical information contributed by posters like Rivkin and Dr. Feuerbach (and others!) is outstanding. Gene's "field work" has been terrific as well.

31st March 2005, 07:20 PM	#8
Battara EAAF Staff Join Date: Dec 2004 Location: Louisville, KY Posts: 7,280	Hey Jens, what type of knife is that next to the katar and how old is it?