474CJ freeze-up

I already looked at that. The strands in all the wire brushes I have are thinner than this thing and they are a little bit flexible. This wire completely rigid. I can not sway it one degree. It still looks familiar to me ...meaning I have a memory of something like it, from a tool ... a piece of wire screen... a filter of some sort. My hunch is that this thing broke off a wire strand or cable inside a honing unit.

Here's my .02 cents worth of forensic prognostication.
The only place that a piece of wire that thick or longer in length could have come from is the oil pan itself. If the pan has a trap door incorporated into it's design.
Compare the wire to the hinge of one of the door/doors. It could simply be left over fall off from the installation process of the trap door. Compare wire diameter to ascertain if it is of the same species.

It's worth a shot....

safety wire?o'ring wire? lifter plunger lock ring ? valve seal wire? welding wire is fairly soft.

Is it stainless?

This darn thing is harder and more inflexible than any such item I have seen. I believe it is a part of a steel wire or cable, a strand .... particle of a larger cable, like seen in those honing units. The honing stones are attached to very stiff steel wires.

I recall taking a freshly rebuilt engine apart many years ago, done by a professional shop . ... inside the crankcase I found an almost complete honing stone that had broken off the honing brush unit.

This thing will not flex one degree ...... look at the oil pump gear. This thing dug into the steel gear like it was a piece of candlewax:

Sounds like spring steel, very similar to a lifter top retaining clip from somewhere.

Mig welding wire.. check it, bet its .023" thick...