Picked 3 SS all thread from the burn pile at marina

They are about 2 foot long and were used long ago in a wooden boat.
They are in good condition. I already used one.
The one I used is non magnetic.
This second other one is also non-magnetic.
It looks and acts like SS all thread.
It does have an overall rusty patina on the surface, it is definitely not mild steel.
It had a wasted ss nut rusted in place on one end, I heated it with a torch and it came off, the All thread was in decent shape under the nut, some slight issues, the nut was corroded all over it's interior threads badly wasted.
I cut off the end where the nut was, so it lost just 1/2" of length. Still too short for my needs.

I also found another SS all thread that is perfect looking laying abandoned near my boat. So will use that as it is the perfect length for the additional bolt hole I drilled into the keel for the repair.

Question is why are the first 2 non magnetic, and the 3rd all thread slightly magnetic?
I thought all these kinds of SS rod are non magnetic.

Old wood boats are cut up and hauled off or burned here for decades. A very popular boat yard. Half the boats here are wood. And a lot are workmen's deadrises.
The ground is covered in old nuts and bolts and screws. Just dig a little and your likely to find lots of stuff. Around my boat, I can park my truck right next to the boat, so I pick up all the screws and huge SS nails and stuff to prevent a flat tire.

I think these 3 all threads were at one time holding together a deadrise keel. It could be the slightly rusty one was burned, causing it to rust.

One of the wood boat guys gave me a decent board riddled with these massive SS ring shank nails. I slammed them backwards out from the board and used a 3 foot pry bar to collect about 20 nails. I don't use nails much, they are in excellent shape about 4 inches long and very thick. Either 3/16 or 1/4" thick SS.

Another guy offered me a 3/4" all thread rod, but I have no use for it. The guys at the yard like my work on the boat, they admire my dedication too.

 

It might be that you have 2 different types of stainless,316 is non-magnetic and 304 is a bit magnetic.

 

I'd suggest a big magnet, and a good relationship with the scrap dealer

 

Here it is ready to go except for me primer paining and smearing with grease.
I sealed it in a layer of JB Weld epoxy.

Both a nut and washer epoxied onto the bottom end.