I have no idea

[Smilodon]

Went back to an old site and found this. Not sure what it is maybe a lock or something. It looks to have A C and not sure about the other stamped inside a triangle.

 

[cheese]

Allis Chalmers tractors used a diamond with AC in it, and then went to a triangle made up of the letters AC. I haven't seen that exact logo, but it may be a tractor part.

 

[ATpro5]

Agreed. Im also thinking some kind of machinery part