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Author Topic: Magnetic knife  (Read 1891 times)

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Offline jayman448

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Magnetic knife
« on: April 17, 2017, 06:52:55 pm »
Over this weekend I had been putsing making myself a knife. The stock is from an old industrial band saw blade so i figured it should be plenty strong. after grinding it has become quite magnetic. its even picking up coins. why has it done this? also ive never made a blade before and im wondering if i ought to heat the spine to make it softer/ if it needs tempering or anything.
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Offline J05H

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Re: Magnetic knife
« Reply #1 on: April 17, 2017, 08:38:05 pm »
Hmm. It is possible to magnetize any ferrous metal, but I don't see how it could be done by grinding. And anyway, modern American coins are specifically designed to be non-magnetic, so I'm not sure what's going on there. If it is simply magnetized, then the effect should disappear when you heat treat it. 
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Offline osage outlaw

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Re: Magnetic knife
« Reply #2 on: April 17, 2017, 08:42:43 pm »
Are you letting it get to hot when you grind it?
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Offline Stoker

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Re: Magnetic knife
« Reply #3 on: April 18, 2017, 02:15:58 pm »
Quote from: J05H on April 17, 2017, 08:38:05 pm
Hmm. It is possible to magnetize any ferrous metal, but I don't see how it could be done by grinding. And anyway, modern American coins are specifically designed to be non-magnetic, so I'm not sure what's going on there. If it is simply magnetized, then the effect should disappear when you heat treat it.

Winner.. Simple grinding will magnetize to some degree. Annealing and heat will fix this.  I think he is one of us Canauks.. Our coins are magnetic
Osage - I agree with you
Thanks Leroy
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Offline J05H

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Re: Magnetic knife
« Reply #4 on: April 18, 2017, 09:28:14 pm »
Quote from: Stoker on April 18, 2017, 02:15:58 pm
Quote from: J05H on April 17, 2017, 08:38:05 pm
Hmm. It is possible to magnetize any ferrous metal, but I don't see how it could be done by grinding. And anyway, modern American coins are specifically designed to be non-magnetic, so I'm not sure what's going on there. If it is simply magnetized, then the effect should disappear when you heat treat it.

Winner.. Simple grinding will magnetize to some degree. Annealing and heat will fix this.  I think he is one of us Canauks.. Our coins are magnetic
Osage - I agree with you
Thanks Leroy

Ahh, well that explains the magnetic coins. I always just assumed you guys' coins were non-magnetic as well. You learn something new everyday.
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Offline jayman448

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Re: Magnetic knife
« Reply #5 on: April 20, 2017, 08:59:31 pm »
indeed i did let the tang get hot while grinding and indeed i am a canuck XD. when it comes to heat treating i have no idea... im doing this by the seat of my pants, care to lend a tip or two?
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Offline J05H

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Re: Magnetic knife
« Reply #6 on: April 21, 2017, 02:36:40 am »
I'd love to help but I really can't. Not knowing what kind of steel it is, you may have to do some experimenting to get the heat treat right. I'm sure someone will have a rough Idea what kind of steel it is based on your description and can give you a starting point.
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Offline Stoker

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Re: Magnetic knife
« Reply #7 on: April 21, 2017, 09:27:07 am »
Bandsaw blades can be high speed steel or bi metal.. Might have to google it or you tube.. Some pics if you can
Thanks Leroy
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