My compass has died (again!)

[Toddy]

This is the third one to do so in the past three years....both my silva ones got a bubble and the last one no longer points North.
My kit usually last me forever, I'm not careless or harsh on it, but I have*no*luck with compasses. Now I'm wondering, is there anything in my bag that I really ought not to keep my compass next to? Is there anything that might de-magnetise it? Similarly, will the compass affect my bank cards?
Just wondering....
Cheers,
Toddy

 

[tomtom]

A knife can affect a compass but in my experience the compass normaly goes back to normal when you move the knife blade away..

also, i was told that air pressure can effect the size of a bubble in a compass.. so even if a compass appears not to have one it may 'develop' one which a change in pressure..

not sure if this is of any help to you!

 

[Goose]

How do you break a compass?
I don't think I have had compass that doesn't point north, except a memorable trip to Angle Tarn in the Lakes, many moons ago and now I know that was to do with the rocks!
Even squaddies don't break compasses!

 

[tomtom]

a large magnetic charge can throw a compass off for good.. i dont know of any kit that would throw it off for good?

a mobile phone or gps powersource maybe?

 

[Goose]

A bit of a long shot Toddy, you dont wear a copper bracelet that has magnets in do you?
How far out is the compass, and is it consistently out in relation to north rather than your self or room you might be in?
I am asking obvious questions but you never know!

Can't think of anything that would realign the poles on a compass, it would have to be a really strong magnetic field, industrial strength motor, maybe?

 

[bothyman]

Toddy

If you have a "Magnetic Personality" that could be part of the problem.

Just a Logical Thought :werd: :thinkerg:

MickT

 

[JohnC]

Is it hanging on a strap banging against something? I believe that can demagnetise metal.

 

[Ogri the trog]

Sorry to hear that Toddy,
Sadly, as with many things, if it contains liquid - eventually it WILL leak! Those that are oil filled (rather than water) might hold off the leak for longer on account of the liquid being more viscous. But in general, this is what stops me buying a really good (read expensive) compass, the knowledge that sooner or later it'll develop a bubble.

Ogri the trog

 

[Grooveski]

A compass went funny on me once, the bag it was in had been absently stored in a hall cuboard next to a set of PA speakers(home-made - no shielding).
It still pointed north but seemed to be taking much longer for the pointer to settle. It could just have been my imagination but I didn't trust it so binned it(it was pretty old anyway).

 

[Toddy]

Thanks folks, I really don't know what I do that kills them I'm starting to think like Ogri and wonder if it's worth buying a *name* compass or would a generic cheapy do, but I'm reluctant.....just in case
The latest one sounds like Groovski's, kind of reluctant to get on with it and do what it's supposed to, so much so that I doubt it's pointing North at all.
I have *no* sense of direction, I have to familarise myself with the landscape all the time so a compass is a 'good thing'. I did wonder about the mobile phone, and my knife and the paint scraper and my Psion too, as being the cause
Ah well, Christmas is coming, we'll see what turns up for good girls

Cheers,
Toddy

 

[gregorach]

That's very strange...

As for your bank cards, no need to worry. Contrary to popular belief, they aren't affected by static magnets - you need an alternating magnetic field of the appropriate frequency to wipe them.

 

[Nemisis]

What about buying a cheap toy compass and using it to test the equipment you carry to test for a magnetic reaction?

 

[arctic hobo]

In terms of demagnetising it, the only thing it could be is a knock or a really strong field... although too strong and it would just remagnetise it another way, which would be noticeable. Large bits of metal (or small ones, if they are close) cause magnetic deviation, and can sometimes exert a small magnetising or demagnetising effect on the needle. This is why they should be "trued" every now and again.
Some compasses do just give out over time, I have few about 10 years old that just don't really turn any more.

 

[Toddy]

I didn't know about a *knock* doing the de-magnetising My bag does get thrown around a lot....that's a possibility. No magnetic bracelets; personality...HWMBLT says I attract hippies and other eccentrics and little boxes ( I *like* boxes!) though people are fun too My bag usually hangs around under the stairs; there is an electricity meter in there behind a door though; I bought a new little one that comes with a carrabiner and it is attached to the strap of the bag....surely they wouldn't have made it like that if rattling around on the strap would de-magnetise it? would they? Bet they did too
I've got one of those little car button ones somewhere, I'll lay it besides the gps and see if it goes wonky with it.

Thanks again folks,
Cheers,
Toddy

 

[tomtom]

Toddy hits 1000

 

[Toddy]

Toddy hits 1000

and .......
*
*
*
*
*
*
I'm waiting for fireworks here, y'know

Hey what can I say...(quite a lot apparently )....it'a cool site, it *invites* conversation

Cheers Tomtom,

Toddy

 

[Nemisis]

Could this compass be toddy proof? http://www.jimmygreen.co.uk/shop/moreinfo.asp?iCatID=75&iSubCatID=102&iProdID=193

 

[Chopper]

Hi Toddy, This is a subject that I have had plenty of experience on.

As far as the bubble goes, providing it is not too big it should'nt really cause any problems, however it really is good practice to always have two compasses to check one against the other.

When it comes to the de-magnetising problem I have had several problems over the years and have never solved the "how did it occur, problem" but, you can re-magnetise it quite easily, and this is how you do it.

1. Get a small magnet, the one I use is 10mm x 10mm x 20mm.

2. Make sure that you use the "North" pole end, if it is not marked and you use the wrong end, it is not a problem, you will have to repeat the following using the other end of the magnet.

3. Hold the compass in one hand, and using the "N" end of the magnet place it on the centre of the plastic / glass cover directly over the needle pivot point and gentley drag it along the "N" half of the needle, do this about a dozen times and that should do the trick, if it dose'nt keep going until it does. The glory of this is that it will either be right or wrong if its wrong, just keep going until it works, there is no nearly right or nearly wrong.

It can be a little fiddly, as sometimes it does try and grab the "S" end of the needle, but patience will over come this.

Now check your work against a compass that you know is correct

MAKE SURE you are magnetising the correct end of the needle, or you will fond that you will be walking in the wrong direction. This brings plesant memories of a scout hike I organised and purpously calibrated a compass 180 degrees out, the scout leader that I gave it to, did not realise, eventhough he was standing amongst another ten compasses that were all pointing the other way, it was only when he started to walk in the oposite direction that is suddenly clicked, that was 12 years ago, and he has to this day, not been allowed to live it down.

Have fun and if you have any problems PM me. Good Luck.

Steve.

 

[Toddy]

Thanks for all of the advice, much appreciated.
I've been promised a new one , if I can make up my mind which one.
I've been looking at this site

http://www.ukge.co.uk/UK/prodtype.asp?PT_ID=105

and now I'm more confused than ever......this could be as bad as knives, people....
Any recommendations? I quite fancy the little ones on page 2 since it was the SIlva ones on page I that died

Cheers,
Toddy

 

[Doc]

The choice of compasses is very wide.

The 'standard' type 4 is very good. Graduations are at 2 degree intervals. The army use it, although theirs are calibrated in mils. The roamers are handy for grid refs.

The type 3 has a smaller baseplate and no roamers. The weight saving is pretty minimal and I wouldn't bother.

The Ranger type 15 is a classic bit of kit. The mirror will improve bearing accuracy only slightly, but it has the twin advantages of a) a mirror, for signalling, removing ocular foreign bodies, etc and b) the fold over cover makes it more robust.
You can get them with a clinometer 'angle of dangle' but most people don't need this - nice for geologists measuring angles of rock strata though. It will also let you check your latitude but only to a 2 degree accuracy (120 nautical miles) so not really of practical use.

I have a Type 54 (made by Silva but badged Brunton - I bought it from the US). Although not as robust as the type 15, it lets you take bearings to half a degree accuracy using the sighting feature. In all other respects it is the same as the Type 4.

To tell the truth, the Type 4 will do everything you want in the UK. If you would normally carry a mirror too, then get a type 15. If you really like navigation, or need the accuracy for aligning antennas etc, get a type 54.

Some of the smaller models have 5 degree graduations. Still useful, but you will get more error when getting a position fix by resection, and may have to walk a bit more along your 'handrail'.