1975-D LMC Collar / Offset

Partial collar errors often co-occur with misaligned die errors. I assume that is because the hammer die whacks the top of the collar and drives it slightly below the plane of the anvil die face.

There was a post awhile back pertaining to a "railroad rim" coin. I don't remember what the coin was in that case but in that case it was not.

This one is what we sometimes call a "railroad rim". Notice how when you look at the edge it has the appearance of a flanged wheel used on the trucks of trains. On some coins, the "flange" is much more pronounced than it is on this one but this one is on the right track:-) (get it?)

As mentioned, it is a partial collar strike.

Thanks,
Bill

Steel to copper contact don't affect the die at the time of the striking. Eventually die wear does happen with continued use of the die, but that is normal. The collar holds the planchet could be affected. But even that would be rare. Most of the time the coins just continue, one like yours and the rest that follows normal. Errors happen and the rest of the coins can continue normal. Just another day at the mint.
Here is a link to an interesting video on U.S. Currency. The 8 choice on the center right shows about coin production. Enjoy.
http://www.history.com/minisite.do?...ini_id=52493