magnetize a blade during sharpining..hummm

V

Vermont woodsman

Joined
Jan 22, 2005
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For the past week ive been interested in this whole magnetized blade thing. So i took a single staple and noticed it sticks to the sharpeded edge of nearly every blade i own, and interestingly enough even the blades on my leatherman; but not the can opener or other tools. I called benchmade today and spoke to customer service and the man on the phone took out his knife and tried the single staple test and sure enough a single staple stuck; so im wondering could sharpining induce magnetism. Sorry if i bore all of you with this but i find it interesting. Any thoughts as to why? The leatherman thing made me think it was the act of sharpining that causes this any thoughts? I know there are ton of smarter people then myself here ,so id love to hear your ideas. Thanks for puttin up with me and my sillyness :)
 
In the 3 years I have been reading various knife forums, I have only read about magnetized blades only ONCE. That was here and just a week ago. Look in this forum just days ago and you will find your answer. The title of the thread your looking for is obvious ;)
 
Hmmmm....

How, pray tell, do you sharpen?

Remember, magnatism results when the electrons in a number of the iron atoms spin in sync. What gets them to synchronize is usually an externally-applied magnetic field.

In the old days, to make a compass needle, you took an iron needle and stroked it on a lode stone which is a naturally-occuring magnet. Sharpening very often consists of stroking the blade over a sharpening stone. I suspect that your sharpening stone has some natural magnatism to it. How interesting!
 
No i didnt sharpen any blades, they all have the factory fresh edges. When i say magnetic im not talking highly, im mean very , very slight. Just enough to barley pick up one staple. Im thinking its sharpening because all my other leatherman tools arent magnetic, just the blade.
 
I thought I have read some where that that knife manufacturers (especially for kitchen knives) deliberately magnetised their blades slightly. This is so that when the knife is sharpened the steel filings will not get into food etc but will remain on the blade to be wiped off.

Any one else ever hear of this before?
 
I think that if anything magnetizing the blade would get more metal shavings in the food. If the magnetization was strong enough some filings would stay stuck to the blade even after you cleaned it, then when you cut your food it could come off. I don't think a significant amound of filings are produced while cutting, I could be wrong though. I mean you will always get some metal into the food, but a little iron is good for ya!
 
All my S30V knives acts like magnets- before shapening and directly out of the box. I don't know why- but S30V seems to be a magnet and a knife...?

Not sure if this is good or bad- or maybe it doesn't really matter... :confused:

Anyone else experienced this with S30V blades?

Jorgen
 
Well, I've toured the factories of several knife manufacturers and have yet to see magnatizing as a manufacturing step.
 
I tested this phenomenon just now with my S30V Military. I didn't sharpen it but rather stropped it. It picked up a single staple. So I guess that at least some blades out there are slightly magnetized. I don't know what difference it makes though.
 
Steel + friction = slightly magnetized steel...Sort of like rubbing a balloon on your head and sticking it to a wall.:D.
 
Now mine often end up magnitized because I stick em to the side of the fridge or something with little NdFeB super magnets. But, perhaps your blades are not really magnitized and the earth is just fooling you!

Have you stopped to consider that iron and steel is more highly permeable to magnetic fields than air? Take two little strips of mu metal and hold them end to end in alignment with the earth's magnetic field and they jump at each other as if they themselves were magnets even though mu metal doesn't have enough residual induction to make a permanent magnet. They are just concentrating the earth's magnetic field lines so they act like magnets, since they offer less resistance to the passage of a magnetic field than air does. A knife can do the same thing, and some steels are capable of retaining magnetism so just leaving one sitting around aligned with the earth's field long enough could weakly magnetize it
 
glockman99 said:
Steel + friction = slightly magnetized steel...Sort of like rubbing a balloon on your head and sticking it to a wall.:D.
Click to expand...

That's static electricity- and not the case with my S30V knives. ;)

Of some reason my S30V blades acts as really good magnets. I can pick up screws and nails without a problem! And no other knife steel in my collection can do that.

Maybe this magnetic property of S30V is one reason why this steel easily get galvanic corrossion- under the right conditions...???

Jorgen
 
I tried this test with a few of the knives in our display cases a few months ago. Most of them seemed to have no magnetism at all. However the knives stored on our wall magnets certainly did.
Maybe just the staples are magnetic.
 
Oh for coincidence!

I used my Kershaw 1415 to pluck the stapled cleaners tag from my BDUs this morning. The stapes, all four of them, stuck quite stongly to the blade. I thought this odd, but soon forgot about it. Then I see this post on the forum!

Of course, I have since gone and experimented. Normaly, I carry an inexpensive K.O. for daily garrison use. I've never noticed the staples stick, and they don't. The only reason I had the 1415 in my pocket was cause I found it in the back of my sock drawer. The K.O.s almost all have 440a steel, and none of them would hold a staple. They DID have an atraction, though. An Al Mar Falcon Talon with AUS8 had a slightly stronger attrcaction. BTW: The Kershaw 1415 is ATS-34.

For a final test, I tried a new BM 9053SBT with 154CM (for "non-garrison" use, if you know what I mean). No attraction.

Now here's my theory: I use DMT diamond bench stones to sharpen my knives. Followed by 3M wet/dry paper in 15/5/.05 micron for polish. My final step is a fairly agresive stropping with leather and green compound. I believe it is the stropping of higher grade steel that applies the attraction. I have used the word attraction because I think it might just be more static than magnatism, and I am not entirely inteligent around physics and electricity.

To get rid of the maganatism, sit and tap the knife on the arm of your chair while you watch TV. The repeted mild taps will dis-combobulate the alignment of the cosmitism in your pig sticker!
 
To further confuse the issue, some grades of stainless steel are non-magnetic. Power transformers above a certain size have their low-side bushings inset into a single plate of stainless steel so that the large currents flowing through the bushings will not induce circulating currents in the transformer tank. When I used to do factory inspections on power transformers, I always carried a small magnet to test for this. If the stainless steel plate was in place the magnet wouldn't stick.
 
There is a small spot on the spine of my Small Sebenza that will pick up a paper clip. It has the BG-42 steel. Several forceful wacks on the edge of my desk did nothing to change it. None of the SAKs I keep laying on the desk would pick up anything, nor would the $5 stainless Opinel I just bought.

Don't know what any of this means. Don't know if it matters. It is interesting though.
 
same thing with my sebenza, not the whole blade; just a small spot. I too noticed the same thing with my sak, they wont pick up anything either.
 
This is usually the point where a thread gets uttery derailed, and goes off on another tangent.

So lemme be the first to give it a nudge (sorry)......

MikeH mentioned the different magnetic qualities of various steels. I would think that this is primarilly a function of Iron Content.

Would it be possible to test the metal type of a given blade with a magnet? Knowing the magnetic properties of any given metal, you should be able to compare that to the properties of an unknown metal.

This is the same way modern vending machines weed out slugs and canadian coins.

This train of thought was born out of an experience I had at a gun show in Alaska a number of years ago. I was admiring some truely beautiful hand made knives, and asked the fellow what kind of steel was in them. I wouldn't have know the difference between S30V and an aluminum soda can at the time, but it seemed like an intelligent thing to ask. I don't recall what kind of steel he said it was, but his message was clear... "It was the very best you could get." Not so. I ended up with one of the prettier ones. None of the prices were outragous, so I felt I had made a good (if uninformed) purchase.

The knife has since be tossed out. The blade broke at the haft after an unscheduled sudden stoppage on a tile floor. Near as I can tell, the metal is some cheap brittle type. Properly treated 440A, while note so "high tech" wouldn't have shattered like that, so I really don't know.

Of course, there are important factors like heat treating to consider when looking at the quality of a blade. But I think that Magnetic Properties would be a good start for field testing the type of steel in a blade.
 
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