Pulled this from circulation yesterday. A 1971-D lincoln in which the obverse appears to be struck through grease (alot of it), design elements are correct size but very mushy with rippled fields. Reverse normal.
Not to doubt you folks, but wouldn't a late state die cap cause the image to stretch, causing lincoln's bust to be larger than normal?
No, you have to understand the life cycle of a capped die. A coin gets stuck to the hammer die, lets say its the obv die. The first few coins struck from this newly capped die will be full brockage pieces with a normal reverse and an incuse reverse. As the die continues striking coins the relief of the exposed reverse on the capped die is rapidly reduced and the image begins to spread. Coins struck now show a normal reverse and a very shallow, enlarged and distorted reverse image. Striking continues and the image on the rev of the die cap is now so flattened and spread that it may not be recognizable. The material covering the face of the die is now thin enough that the design of the obverse die is beginning to show through. Coins struck now will have a normal reverse the obv will show little or no evidence of the distorted reverse but will show a very faint image of the obv. Striking continues and the metal covering the die face grows thinner and thinner. Coins struck show a stronger and stronger image of a normal obv. Eventually the obv looks almost normal, but possibly like it was struck through a single layer of metal foil, which in effect is exactly what has happened. The metal of the cap has been pounded to foil. In some cases the "foil" over the face of the die will tear and pieces of it may fall away. In that case areas of the obv will look normal and others will show the strikethrough effect. In no case does the image of the obv as it shows through the cap appear enlarged.
Thanks for that description, Condor101, its useful to see the progression of the strike through detailed. It makes it easier to visualize.
