When examining clipped planchets, the side of the coin opposite of the clip will exhibit what is know in the coin industry as the "Blakesly Effect". During the upsetting process or rimming of planchets, if a section of the planchet is missing, there will be an absence of pressure in that area causing the opposite side of the coin to be flat and not as formed.
Image By Ed Lott
Image By Ed Lott
Image By Sean O'Connell
Image By Ed Lott
Below is a coin that was first thought to be a double clip, but when compared to the webbing it would be impossible.