compass question

RescueRiley

RescueRiley

Joined
Mar 22, 2006
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So ive assembled a small psk in an altoids tin which is ranger banded to the sheath of my f1....I cant fit my compass inside the tin (and since it is one of my most frequently used tools I slipped it into the ranger band....however i noticed when in such close proximity to the kit and the knife it varies from north...when I remove it it quickly readjusts...my question is if storing the compass this way will damage it and make it inaccurate?? thanks!
 
It's not suppose to. Military compass are regularly stored in close proximity to other metal objects, and that does not affects their accuracy.
 
I've heard of this also in the past and think it's just one of those old wives tales.
i have compasses that have been stored with my knives for decades with no ill effects.
 
I bought a Silva compass and on the instructions it says to keep away from any magnetic sources such as knives and even car dashboards ( something to do with the engine proximety ). I also heard where a shop was scanning the sticker with a bar code on the compasses they were selling and everytime they did so it ruined the compass !!!
 
I have seen however , 2 compasses stored near each other , one can reverse polarity . I know one person that did this , twice. :rolleyes: Perfectly accurate , other than the 180 degree part .
Phil
 
If the objects you are storing the compass next to are signifigantly magnetic (enough for you to detect it (knife will pick up staples, etc.)) then you may have a problem.

With the car engine, you have coils that generate the electricity for the spark plug and an alternator which produce signifigant magnetic fields. I don't think that keeping a compass on the dashboard would be close enough for these to cause a problem though. I bet Silva is just covering their butts.

The checkout may have had a magnetic pad to disable the RFID security tags that some stores use. These would be plenty strong to mess up a compass.
 
A few years back I had a watch with a mini-compass built into the band. I wore it while arc welding and the electro-magnetic field that was generated ruined the compass.
 
It definitely is possible to change the polarity on a compass with a magnet, I've done it by moving the magnet across the top of the compass several times. The good news is that you change change it back the same way, I've done that too.

The danger obviously is if it ever happens w/o your knowledge, can you say "lost" (or at least very confused)? The best solution is to keep it away from magnets or other compasses and remember plain old carbon steel objects can sometimes be magnetic too. Put them together, bouncing along in your pack for a while and you have a potential problem. I always carry at least two and they ride in separate pockets.
 
pitdog said:
I bought a Silva compass and on the instructions it says to keep away from any magnetic sources such as knives and even car dashboards ( something to do with the engine proximety ). I also heard where a shop was scanning the sticker with a bar code on the compasses they were selling and everytime they did so it ruined the compass !!!
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I'll bet the dashboard problem is the speakers that may be there. If you haul a radio with a speaker, keep that in mind. The issue in the store is the security tag deactivator rather than the bar code scanner. The security deactivator is usually a plastic pad on the counter that will also wipe out your credit card. I could see that raising Cain with a compass.

I wouldn't worry about the tin, but other steel objects will vary. I liked the staple test-- easy. I have a tool for magnetizing and demagentizing my computer repair tools-- it's a magnet. Stroke one end to magnetize and the other to demagnetize. http://www.craftsmanstudio.com/html_p/DA40010.htm

I've made it a habit to avoid any magnetic catches in my gear. Nalgene came out with a magnetic catch bite valve for their hydradation bladders, which is asking for trouble on the trail. Your compass should be removable from a lanyard with other steel objects like a small knife, etc. I use Silva keychain compasses for PSK backups and they come with a brass ring-- don't replace them with steel: I've tested and it does throw them off in use. I haven't tested a firesteel-- I wonder.....
 
If you can't keep your compass in your car or next to a knife, how are u suppose to get anywhere? Walk? with no knife?

I kept mine in a tackle box next to a fillet knife for over ten years. Took it out last night to check with the GPS, they both point the same way.
 
this why the military went to GPS systems because the paper mache equipment to protect the compasses just would aways be breaking down.:D
 
Long term proximity to steel alloys won't hurt a mag compass but it will affect accuracy. Compasses on steel boats are compensated with steel 'bobs' or balls to allow for this. The easiest fix is to swing the compass with the car. Use GPS as your reference and make up a correction card for the mag compass. That's typically how light aircraft are done.
Magnetic fields tend to be 'contagious', so be careful there. An optical barcode scanner won't affect the compass and I'd be leery of buying a compass from a store that puts rfid tags on them in the first place...
 
I find that the compass I added to the outside of my PSk kit would still point the same way but it would be slightly slower to adjust.
 
The advice to keep the compass away from steel relates to when it is in use. I too have stored compasses next to knives for years without any damage that I can detect.

Every compass sold by Dicks, Walmart, etc goes through a barcode scanner. That includes a couple that I have -- no problems for mine.
 
Thomas Linton said:
The advice to keep the compass away from steel relates to when it is in use. I too have stored compasses next to knives for years without any damage that I can detect.
Click to expand...


Same here. A couple years ago a co-worker gave me an old WWII era wrist compass that he's had in his shop toolbox for many years. It's beat all to hell and scratched to the point it's kinda hard to read, but still accurate.
As for car dashboards, there are probably millions of cars, trucks, RV's, SUV's etc. travelling around the world with dash mounted compasses that also work well.
And the military went with GPS for speed and accuracy. Less chance of mistakes under stress. When GPS acts up it's back to the map and compass.
Slower and more prone to human error, but very accurate if the soldier does his part. They still train to get some distance from metal, such as rifle, side arm, bayonet etc..
 
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