Read our article on off-center strikes we wrote for PCGS on their website:

https://www.pcgs.com/news/the-popular-off-center-strike

Struck Through Errors

Building an Error Coin Collection

by Jon Sullivan

U.S. Coins on Argentina 10C Planchets

by Jon P. Sullivan

Split Planchet Jefferson Nickels

By. Jon P. Sullivan

Building An Error Type Set

by

Here is an excellent article on the subject, put out by NGC. It will describe in detail what they are, and how to detect them. http://www.ngccoin.com/news/viewarticle.aspx?IDArticle=4412&Wheel-Marks

Comprehensive Error-Variety Checklist

Compiled by Mike Diamond

This checklist is my attempt to compile a comprehensive listing of all known variety and error types, subtypes, and associated effects.