Isn't that illegal?

Its only illegal to deface money to gain advantage. Back in the days coins were actually made out of precious medals, people would file just the outer edges off of a ton of coins down and use that part to make more money etc etc. That is still illegal.

United States Code
TITLE 18 - CRIMES AND CRIMINAL PROCEDURE
PART I - CRIMES
CHAPTER 17 - COINS AND CURRENCY
§ 333. Mutilation of national bank obligations

“Whoever mutilates, cuts, defaces, disfigures, or perforates, or
unites or cements together, or does any other thing to any bank bill,
draft, note, or other evidence of debt issued by any national banking
association, or Federal Reserve bank, or the Federal Reserve System,
with intent to render such bank bill, draft, note, or other evidence
of debt unfit to be reissued, shall be fined under this title or
imprisoned not more than six months, or both.”

That says otherwise. Same applies to Ireland.
I think the actual law was amended.

/edit Never Mind apparently it does not apply to coins at the current time.

This post was edited by King Atrhur on Jul 10 2014 10:48am

Actually we used to beat the edge of a quarter with a table knife handle, rotating the quarter each strike...before we drilled through. When done the ring was about 1/2" wide and banded silver, copper, silver.

The one in the anime above was made slightly differently. It was drilled first, the pressed onto a shaft slightly larger in diameter than the pre-drilled hole. The modern way is a lot faster.

This post was edited by Ghot on Jul 10 2014 01:30pm