when going through some 1953 s pennies i saw this one and it looked like it was missing the letter I and the L and B are barely existent. i was wondering if this is post mint damage or did it genuinely come from the mint missing the letter I? some pics: http://i76.photobucket.com/albums/j36/widemouthmason/Mobile Uploads/IMG_4470.jpg http://i76.photobucket.com/albums/j36/widemouthmason/Mobile Uploads/IMG_3248.jpg http://i76.photobucket.com/albums/j36/widemouthmason/Mobile Uploads/IMG_4039.jpg
so the grease gets stamped in the form of a letter or it just creates enough of a buffer between the planchet and the die that the strike ends up being weak wherever the grease exists?
Grease cannot be compressed, so if it does not have a means escape from the cavity it occupies, it will not allow the metal to flow into the devices in the die. Steve
In the case of minting, grease is not grease like you lube your car with. It is a combination of metal flakes, dirt, and anything lying around at the mint - all being all held together with what probably used to be die grease. Not only is it incompressible, but it can be nearly as hard as the die.
+1 When people talk about "grease" in minting, it is like Rlm states metal shavings and other very hard debris held together by the grease. This is why the mint has to carefully clean the dies during the day or this "grease" could obliterate the entire design. I used to work in auto part manufacturing, and know how carefully they had to clean up in order to minimize errant shavings from destroying press production. Anytime you work with metal those dang little shavings get everywhere.
