think it is aluminium

[buckeyehunter]

here again i have no idea, strange shape to just be a chunk of aluminium, had to be used for something

 

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[dg39]

could be the knock out of a hole in a electrical junction box. Not magnetic i presume? They do make alum. junction boxes and conduit for wire .
dg

 

[Boobydoo]

It's hard to say by the photo and info provided, not much to go on.

My guess is that this might have been used as a machine leg/foot support.
Put between the end of the leg of the machine and the floor to protect the floor from being damaged by the angle iron leg of the machine. It looks like it has a lot of grime on it and some dents?

This is just a total fly-by guess of course.

Smiles1
BDoo