Magnetic Blade

[Para3]

I was touching up my Para3 M4 blade on an extra fine diamond stone this evening and noticed that the blade or stone felt magnetic ?
I grabbed another knife with a maxamet blade, hit the stone a few times and nothing, no pull.
Tried the M4 blade again and felt the same magnetic pull. I then held a paper clip to the blade and sure enough, it stuck to the blade ?
I keep all my knives togeather in a nightstand drawer and started checking all the blades, even a couple of 52100 blades. The Para3 M4 was the only one that exhibited the magnet pull. Has anyone else experienced this or can explain why this happened ?
Thanks in advance for your comments.

[The Meat man]

If you get any piece of iron or steel close to a magnet it will become magnetic itself. My guess is that either you, or somebody else, got the blade against a magnet at some point.

A lot of the knives I regularly carry exhibit slight magnetism. I'm working around steel and using magnets a lot during the day though, so that probably explains it.

[Sharp Guy]

^ Yep! What Meat said.

The sharpener I use to reprofile my knives uses a strong magnet to hold the blade in place when sharpening. When I'm through sharpening the blade is magnetized. I then de-magnetize by passing the blade over the side of another strong magnet I have.

[Bloke]

... using magnets ...

[Para3]

Thanks for the feedback guys.

[awa54]

Since knife blades don't generally fit in a regular size tool demagnetizer, you'll need a larger one to get the job done... A few years back when cassette and video tape was still in regular use, bulk tape erasers were a common thing to find, they generally looked like a small clothes iron and can be used to randomize the magnetic field of any material that has only moderate coercivity (even old HD floppy disks are immune to a bulk eraser, but it works on analog tape and most metals just fine), one of those ought to fix your blades and diamond stone no problem.

Or if you aren't having metal filings stick to your M4 blades all the time and the attraction to the hone doesn't bother you, don't worry about it!

[Sharp Guy]

Since knife blades don't generally fit in a regular size tool demagnetizer, you'll need a larger one to get the job done... A few years back when cassette and video tape was still in regular use, bulk tape erasers were a common thing to find, they generally looked like a small clothes iron and can be used to randomize the magnetic field of any material that has only moderate coercivity (even old HD floppy disks are immune to a bulk eraser, but it works on analog tape and most metals just fine), one of those ought to fix your blades and diamond stone no problem.

Or if you aren't having metal filings stick to your M4 blades all the time and the attraction to the hone doesn't bother you, don't worry about it!

I've had one of these in my toolbox for years. It's never seemed to work very well, even for screwdrivers.

https://www.amazon.com/Wiha-40010-Magne ... magnetizer

This is similar to what I used when I made tooling when I worked in manufacturing. We used it to demagnetize tooling after it was on the magnetic chuck of our surface grinder.

https://www.amazon.com/HHIP-3401-0602-H ... magnetizer

I wonder how well this one works? For $10 I might just try it out.

https://www.amazon.com/GreatBBA-Demagne ... magnetizer

What I've been using is a small but fairly strong magnet. It's cylindrical and about 1 1/2" long by 3/4" in diameter. I pass the blade over the side of the magnet near the center (between the two poles) without touching the magnet. It seems to work well. I reprofiled my V-Toku Delica a couple weeks ago. After reading this thread last night I remembered that I forgot to demagnetized it. It had a strong charge and it took some effort to get it demagnetized. It's fine now and won't even pick up a small paper clip.

[awa54]

The watch demagnetizer probably has a much weaker field strength than a "real" tool demag. The reason I mentioned tape erasers is that they have a strong enough field to work on tools and nobody uses them for their intended purpose anymore, so they can be had fairly cheap off ebay (search "bulk eraser" or "tape eraser").

[Sharp Guy]

The watch demagnetizer probably has a much weaker field strength than a "real" tool demag. The reason I mentioned tape erasers is that they have a strong enough field to work on tools and nobody uses them for their intended purpose anymore, so they can be had fairly cheap off ebay (search "bulk eraser" or "tape eraser").

Yeah I looked at it again after I made my post. That probably wouldn't work very well for demagnetizing a blade. I'll stick with the way I'm currently doing it. It works well and it's already paid for. :)

[Para3]

Thanks for all the replays, as of today the knife seems ok, no more magnetic pull. No idea what caused it or what made it go away ? Maybe it's haunted, LOL.

[Mstach07]

I’ve experienced slight magnetism caused by my wallet/money clip (magnetic) combo. Both go into the same pocket. It too eventually goes away on its own

[Evil D]

I had a weird issue like this back when I first joined this forum while sharpening a Caly 3. This was done on a Lansky...where there are NO magnets, and to the best of my knowledge the knife hadn't been in contact with a magnet before reprofiling it. You can even see the magnetic field where the metal dust is accumulating.


(boy, camera quality has also improved a lot in the last 8 years)