Honest questions

B

BigNate

Joined
Aug 25, 2006
Messages
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First let me just take a second to say that although I don't post much at all I've read lots and find some very interesting comments and thoughts on things that don't interest the general public. THANKS FOR THAT!

My questions stem from one of the links I was just reading about survival compasses. It was stated that the survival compass shouldn't be kept in a tin or by a knife or other metal that "will" ruin the compass.

So do you carry a button compass in your psk tin? Knife handle?
Have you ever "ruined" a compass?

The reason I was looking yet again for button compasses is I just bought a CRK one piece and was going to put a Pyser compass in the handle cap. I know Bill Sanders has a knife with removable scales that comes with a small compass (among other things) in the handle. So if you have one in close proximity to steel how long until it isn't accurate?
http://www.billsandershandmadeknives.com/products207781.html
http://www.bestglide.com/FB1605_Info.html
http://www.tadgear.com/shop.php?id=444
 
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this doesnt actually happen, I just went and grabbed a compass from one of my kits (which happens to be metal) that has been sitting around for over a year and the compass still points north perfectly! im not sure about knife handles how ever I did have a small tin kife in the kit as well.
 
Well I DO know that metal can throw a compass off. For instance if you lay your map and compass on a truck hood, the metal will throw the compass off. However, when you pick the compass up away from the metal, it'll go back to pointing north. I've also heard that a magnet can reverse the polarity of compass. Turning the needle from pointing north to pointing south.
 
I think there is a big difference between storing a compass in a metal container, whether a tin or a knife handle, and using it in proximity to metal. The first shouldn't be problematic, whereas the second can give you false readings. I think you could store a button compass in the handle of CRK one-piece, but I wouldn't actually mount it inside the handle, because that could throw off your readings when you use it.
 
I've never had a good compass lose accuracy, and I've never bothered where they are stored apart from not keeping them with actual magnets. I'm not saying it can't happen though.

I have seen very cheap button compasses get reversed or demagnetized when stored near big lumps of probably magnetized iron. By very cheap, I mean the 5-for-a-£ ones I used to buy for the kids to do science experiments with in school. Most of them were stolen or broken within a month or so, so no point buying good ones.

I've noticed a few compasses advertising the use of NIB (Neodymium Iron Boron) magnets for the needle, purported to be more resistant to such issues. NIB magnets are currently the strongest commonly available for their size.

I do keep my big NIB magnets away from my compasses, and everything else as well for that matter. Big NIB magnets are frightening!
 
IMO button compasses are usually of poor quality and even the best ones aren't very accurate. My Commenga remains in its US style compass pouch with big metal ALICE clips, it is still extremely accurate. I think it depends on the construction quality of the compass, these Commengas were built to be nuked.
 
Like a previous poster mentioned, some compasses can 'reverse'. I experienced this myself when out hunting in dense bush where I couldn't see any landmarks. The direction my compass was indicating didn't seem right, and fortunately my hunting buddy had another compass which was correct.

If you have a rough idea where north is (using the sun etc) then you can check your compass against this. I can't see why a compass needle could just be a 'little bit' inaccurate. I think any magnetized needle will always align itself with the earth's poles.... although the colored end may point in the opposite direction to what you are expecting.

I dont think it hurts to store a compass in or near iron objects. I have carried one in the glovebox of my car for a long time with no apparent bad effects.

Best wishes... Coote.
 
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coote said:
I can't see why a compass needle could just be a 'little bit' inaccurate. I think any magnetized needle will always align itself with the earth's poles....


Best wishes... Coote.
Click to expand...
Metal objects can alter the local magnetic field which will push/pull the needle slightly. Electronics can do the same thing. Hold a compass near a computer or even a cell phone and it'll probably stray from North.
 
As others have stated the only thing you have to worry about is reversing the needle. I've had it happen once and saw it two other times on the trail. EVERYONE should have some way of finding general direction with enough accuracy to tell you if your compass is reversed. A compass shouldn't replace basic navigational awareness.

The CRT caps are aluminum.
 
XMP said:
I think there is a big difference between storing a compass in a metal container, whether a tin or a knife handle, and using it in proximity to metal. The first shouldn't be problematic, whereas the second can give you false readings. I think you could store a button compass in the handle of CRK one-piece, but I wouldn't actually mount it inside the handle, because that could throw off your readings when you use it.
Click to expand...

I have a compass mounted in my CR Aviator. While the knife is A2 steel, the removable butt is Aluminum. So, the compass is in Aluminum, which doesnt affect its performance..as long as you arent holding the knife and butt in the same hand, while navigating.
 
I agree Shotgun. I wasn't very clear in my post. What I should have said was in the absence of any stray magnetic influence I can't see why a magnetized needle would do anything except align itself exactly with the earth's magnetic field. But sometimes, apparently, a compass needle can be reversed or not marked properly in the factory.

Local 'natural' magnetic influences may be a problem. A few years ago I was trying to find some boundary pegs on a remote property. I had a compass bearing and some landmarks to work with. I had a high quality, liquid-filled army compass and I was walking along the bearing line that I had calculated... aided by some aligned landmarks. The area is defined as 'mineral belt' country and it is completely open and wild. Within the distance of a few paces I saw the compass card shift by about six degrees while walking along the same straight line. I guess it was due to a big concentration of iron in the ground nearby.
 
The Black Cuillin on Skye, Scotland is infamous for making compasses go haywire. The mountain is largely made of basalt and gabbro. Great for gripping when climbing, if you skin is hard enough, but highly magnetic.

Hmm... not been there for a few years now. I'm off to the Highlands tomorrow for a week with the misses - might have to have a trip over to Skye!

Cuillin07.jpg
 
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