Niewmismatic Error Coins

Mexico Silver Trade Dollar 1862 With Rim Clipped Planchet Error
Rarity: RRR
Trade dollars are silver coins minted as trade coins by various countries to facilitate trade with China and the Orient. They all approximated in weight (26.90gm) and fineness (.900 Silver) to the Spanish dollar, which had set the standard for a de facto common currency for trade in the Far East.
Mexico
Following independence in 1821, Mexican coinage of silver reales and gold escudos followed that of Spanish lines until decimalization and the introduction of the peso. The Mexican 8-reales coin  continued to be a popular international trading coin throughout the 19th century.

Coin blanks are punched out of long metal strips using a high-speed press. The strip is unwound from large rolls and fed through the press automatically. Several times per second the punches descend pushing out the blanks on the downstroke and leaving holes in the strip on the upstroke.
On each cycle the feeder mechanism pushes the strip far enough through the press that the punches descend onto clear metal.Occasionally, however, a misfeed can occur where the strip isn't fed through far enough. When that happens, the punches strike an area of the strip which overlaps the hole left by the previous strike. The result is a blank with a piece missing. If the blank makes it all the way through the coining process then the result is a coin with a "bite" out of it.
Note that in no sense is the blank, or the planchet it becomes after rimming, "clipped". Nothing removed the metal; it was never there to begin with so a more accurate description would be something like "incomplete planchet" or "partial planchet". Nevertheless the term bitten or rim clipped planchet is commonly used to describe this error.
This Mexico Silver Trade Dollar shown on this page are a good illustration of the Rim Clipped planchet error showing a curve rim clip. Clips are normally curved because the blank was punched from an area overlapping the hole left by a previous punching.