First, let me say that the dime described below came in change at a cash register. I did not break it out of a proof set. I have a proof 2005-S Roosevelt dime that has a high rim that at first I thought had been removed from a bezel, but the reeding is undamaged. The diameter of the coin is 1.69 mm, which is very close to the nominal diameter of 1.7 mm. However, the thickness measures 0.15 mm, compared to other dimes that measure 0.13 mm. It is possible that it was struck with more than the normal pressure and then the raised rim was created when the coin was reeded? (I am guessing that the coins are first struck and then separately reeded.) I have attempted to upload a photo showing the proof coin beside a 2006-P dime. Any information would be appreciated.
Thanks, for your input. That would mean that this is just an impaired (circulated and touched who knows how many times) proof Roosevelt dime. I have never handled a proof dime before and thought it was unusual for the rim to be so thick. I don't have a proof dime to compare it to that is out of the mint plastic holder. Thanks, again.
Thickness of the rim is a function of the pressure of the strike. The higher the pressure the better struck up the edge will be and the higher the rim. The proofs are struck at a higher pressure and they are struck twice. This results in what you see on your coin, a wide squared off edge where the edge meets the rim at a nice square edge. Sometimes this can happen on a business strike but usually the edge will either round over to the rim as seen on your 2006-P, or you will even see a bevel between the rime and the edge.
Oh ... Now I see! Thank you for an understandable and simple explanation. I knew that proofs were struck twice but didn't think about how that would emphasize the rim. Well done.
