Compass help?

M

marsupial

Joined
Apr 25, 2001
Messages
705
Just wondering if anyone could suggest a place to buy either a SAS survival compass or a True Nord brass compass??I found the little SAS compass on a site but it was like $33 or something?Anyone know a good place to get either?
 
try tadgear.com

Between the two, I would recommend the TruNord rather than the small SAS compass.

S.
 
Tru-Nord had a website:

Tru-Nord

I'm guessing they're still available directly from them.
 
I have a brass match case from Cabela's that has a nice oil filled Silva compass in the top of it ($16 I think). Have a look either at the web or the post called Fire Piston in this forum. The brass case is pretty heavy but they make an Alu one too IIRC.
 
I second the TRU NORD recommendation. Very well made and they are NOT liquid filled. I'm sick of bubbles. Bubbles are manageable with a needle compass, but render disc type compasses useless. The only time I consider liquid filled compasses is when in watercraft.
 
Neanderthal said:
Yet ! ........
Click to expand...


Is this something you have experienced with the Marbles compass? To be honest,I've never had a problem and don't understand how a bubble which is trapped air can suddenly appear in a sealed/waterproof orb.These Marbles compasses seem to be of high quality,in fact,I think they might even be manufactured by tru-nord for Marbles.
 
I was speaking of liquid filled compasses in general. The problem seems to occur most often in very cold temperatures or very high altitudes, but have had the experience under more moderate conditions. I, too, find it difficult to understand how the bubbles form, but they surely do.
 
hay man,

If you try any brittish army store you will gat a real SAS compas for sure, postage should be cool if you sugest to them the best method, I get people to use Global priority mail when i buy from over the big pond for instance.
 
If you unscrew the marble's compasses you'll find that between the fine brass case rides a pedestrian plastic compass body.

Leave it in your car in Arizona temps and you'll find the compass face warps so that the compass can no longer rotate.

Marbles will be happy to replace the compass for a shipping charge only, but I'd suggest you just buy a Tru nord and be done with it.

These are my experiences only.
 
My understanding is that a bubble forms in a compass due to the different rates of expansion and contraction of the compass body and the liquid. The bubble is really a vacuum that develops when the liquid does not expand as much as the case. I read that leaving the compass in sunlight may eliminate the bubble. I did quickly warm a button compass with a bubble and the I could watch the bubble shrink to almost nothing. However, the compass cooled just as fast and the bubble returned. I have not tried warming it slowly for a long period of time yet though.
 
Just to clarify,I was mistaken about the Marbles compass being liquid filled.So I guess if your not a fan of liquid filled compasses,than Marbles should be fine.
 
greg c said:
If you unscrew the marble's compasses you'll find that between the fine brass case rides a pedestrian plastic compass body.

Leave it in your car in Arizona temps and you'll find the compass face warps so that the compass can no longer rotate.

Marbles will be happy to replace the compass for a shipping charge only, but I'd suggest you just buy a Tru nord and be done with it.

These are my experiences only.
Click to expand...



I couldn't unscrew mine,but it appears visually Marbles may have a plastic "crystal" Good to know what can happen in extreme heat.What exactly is the Tru-Nord's cystal made of to avoid this same type of problem?Thanks for the info,that is why I like this place.Can get good feedback and avoid potential problems in the field.Thanks!
 
Tombstone- the new Marble's are liquid filled, the old ones were not. So if you've bought one lately, it's got liquid in it!

The warping of the Marbles was actually the black rotating face with the compass rose printed on it- not the plastic crystal! The Tru nord's also have a plastic "crystal" but the rose is printed on white plastic- maybe this means that the compass won't warp as badly in sunlight, maybe it doesn't- I'm not going to try!

FYI:
The construction of the Tru nord is such that there is a needle at the base of the bottom cup and a coned out bearing in the compass bar that rides on the needle. There is no liquid in the compass.
 
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