1975 20 centavos on wrong planchet

Kkathyl

This one has me puzzled. Error coin or something else?

Insider2

Someone probably trimmed the edge. Now how can we be sure? What should we look for as a clue?

MasonG

@Kkathyl said:
Error coin or something else?!

Something else. Part of the planchet is missing.

Kkathyl

@Insider2 said:
Someone probably trimmed the edge. Now how can we be sure? What should we look for as a clue?

If you are to trim a coin you would look for a sharp start area and discoloring sides.

Having received this from a master coin collector it does not sound likely he would bother trimming such a coin. I will review to see if any bimetallic pieces issued. It just makes no sense to me yet.

MasonG

Mexico didn't issue bimetallic coins until 1992, the coin pictured could easily have been made using a grinding wheel. What did the master coin collector tell you about the coin?

Abuelo

I think someone messed with the flan. The edges are irregular and is not even round.

MasonG

Here you go...

Kkathyl

Agree

Insider2

@Kkathyl said:

@Insider2 said:
Someone probably trimmed the edge. Now how can we be sure? What should we look for as a clue?

If you are to trim a coin you would look for a sharp start area and discoloring sides.

Having received this from a "master coin collector"

?

it does not sound likely he would bother trimming such a coin. I will review to see if any bimetallic pieces issued. It just makes no sense to me yet.

When a coin is struck on the wrong size planchet it spreads out. Your coin shows no evidence of this.

@Abuelo said:
I think someone messed with the flan [planchet]. The edges are irregular and is not even round.

No one altered the planchet. The coin was struck and then altered outside the mint. An image of the edge would prove it. Additionally, as you pointed out the irregular, multi-faceted shape of the coin screams out "ALTERATION."

carabonnair

The result is a little light, but maybe trimmed to pass as a US dime in a vending machine?