1932 Irish Farthing, PMD?

Hello.

Just had a question on what would cause this kind of PMD?

Fairly low mintage coin (192,000), but it looks as if someone (or some kind of machine) spent a long time grinding the rim down.

This was in an estate lot and was set aside in flips, so whoever had it prior to me thought it was worth separating. Maybe they thought it was clipped?



A few spots of wear, but generally no raised metal around the edge.



Full coin shot.



One side is more pronounced than the rest, but there are a couple areas which are a little flatter also. Compared to another similar coin, it is missing most of its rim.



The biggest edge. You can see there is a little rounded off spot as well.



The edge at 30x mag.



The edge at 60x mag. Found this interesting because I figured damage would run parallel to the coins edge (if someone were scraping it to wear it down quickly), but this seems to run across the edge.

Thoughts?