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Compass and steel #561110 11/06/10 11:39 AM
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Ok, this is for all you scientific folks and us ordinary users. IF you have a small button compass such as the one on the Firesteel tubes, AND have a loop to hold it on your knife sheath, the compass will always point to the knife, right? Ok If this is so, will it have any affect on the compass when removed from any influncing metal, STILL POINT to magnetic North? Seems to me that it should, but will it?


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Re: Compass and steel [Re: SkunkHunter] #561111 11/06/10 11:51 AM
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I do believe so, the steel isn't changing the polarity, just adding something other than the magnetic pole to swing to. As soon as you remove that influence, it should swing around to north


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Re: Compass and steel [Re: MrOverkill] #561112 11/06/10 11:58 AM
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MOK, that's what I thought, but then again I thought that over the long haul it may change it. Perhaps I should have asked the same question about the military lensatic compass. You know the one that "Freezes" the needle when you flip the little magnifier arm down IF you flip it down with the needle NOT pointing to north.


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Re: Compass and steel [Re: SkunkHunter] #561113 11/06/10 12:07 PM
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I've never heard of that problem


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Re: Compass and steel [Re: MrOverkill] #561114 11/06/10 12:36 PM
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But I don't know much


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Re: Compass and steel [Re: MrOverkill] #561115 11/06/10 12:41 PM
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Haha, do any of us really?


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Re: Compass and steel [Re: SkunkHunter] #561116 11/06/10 12:43 PM
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naw, but some know more than others


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Re: Compass and steel [Re: MrOverkill] #561117 11/06/10 03:50 PM
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Randy, send me your set-up and I will try an experiment or two with it!


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Re: Compass and steel [Re: sumoj275] #561118 01/01/11 01:10 AM
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Hi,

To demagnetise metal you have to scatter the orientation of the magnetic fields of each individual atom.

This can be achieved by a few methods.

Heat the metal up past its Curie point.

Hit the metal multiple times really hard.

Move an opposing magnetic field against the metal's magnetic field multiple times. This is usually done with a Degaussing unit which cycles a strong magnetic field 50 or 60 times a second against the object to be demagnetised. If you've ever seen a tape wiping machine (for old magnetic tape) then this is Degaussing unit.

Now since the compass is able to float - it always links its magnetic field to the opposing field of the steel - so it doesn't have an opposing field forced against it since it can just move with the field. The floating action also acts as a shock absorber so impacts don't affect compasses. The only thing you have to worry about is heat. The Curie point for iron is about 700 Celsius - about 1300 fahrenheit.

I hope this helps.

Cheers,

Harley.

Re: Compass and steel [Re: harlequinn] #561119 01/01/11 03:37 AM
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Heck of a first post harlequinn.
I've read where knife makers heat the steel up to where it loses its magnetism as part of the heat treating iirc.

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Re: Compass and steel [Re: myketheknife] #561120 01/01/11 07:00 AM
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Harlequinn, WELCOME TO THE YARD! It's a friendly place with a lot of nice folks. A lot of, unlike me, are pretty smart and can give very informative answers on a variety of subjects. I see that you as well are very well versed. Keep up the good work, don't be shy.


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Re: Compass and steel [Re: SkunkHunter] #561121 01/01/11 11:23 AM
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harlequinn Offline
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Thanks myketheknife and SkunkHunter - it's nice to be welcomed.

Happy new year.

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