I just picked up my order of stainless steel parts to install my deck compass. Low and behold, they are slightly attracted to a magnet! It turns out that some stainless metals are magnetic. See https://www.scientificamerican.com/article/why-dont-magnets-work-on/
I would think that this would matter with a deck compass, but by how much? And where can I get non-magnetic nuts, nylocks and washers? Home Depot isn’t the answer it seems. Or should I just go with what I have?
A single set of one bolt, 2 washers, and one nylock is enough to move the compass by about 2-3 degrees. But… when all four are in, shouldn’t they cancel each other out?
On the other hand, the 4 screws supplied are completely non-magnetic. I would just rather use bolts/nuts instead of sharp pointy screws.
The problem for accuracy would be that as the needles gets closer to the magnetic bolts/nuts/washers, it would deflect more, so you would have a reading that is foo in some places, and might be good in other places. I would think you could see this by setting the compass on a board, and installing the bolts/nuts/washers loosely, then rotating the board to see how the compass reads, comparing to say a separate compass held far enough away to not be affected. How much it matters depends upon how much accuracy you would like to have. I would get different fasteners, myself, but then I do not have a deck mounted compass, so you need to think about it for yourself.
You might try West Marine, they have quite a selection of SS fasteners.
McMaster sells Type 316 bolts at least… searching now.
Oooo, West Marine, yes, good call!
Yu can buy a deck compass with a plastic case that has bungees attached to it and secure it with hardware some distance away from the compass.
Thanks, but I already own the Brunton compass that fits in the deck receptacle.
Favorite part of our local hardware is the “small drawers” section where you can find nylon nuts, bolts, and washers. Back in the day I zip tied a deck compass to my deck rigging and it worked quite well.