Interesting 1916 (P) Mercury dime

[coinsandmedals]

In the process of digging through some of the coins I stuffed away years ago I came across this Mercury dime. I remember putting this coin away for two reasons, the first being the odd patina and the second because of the rim. What struck me odd is that I purchased this coin as a kid from an old-time collector who seemed just as puzzled by it. Oddly enough, nearly a decade later while attending the ANA summer camp (maybe 2013?) I found another Mercury dime of the same year and mint that had nearly the same patina and identical rims. Looking back now I wish I had purchased his coin. On a trip back to my home town in North Carolina a few years ago (maybe 2015?) I attended the local coin show and found another Mercury dime (same year and mint) that had the same appearance and identical rims. Again, I wish I had purchased that coin as well. Anyways, I post this to ask if anyone else has seen a mercury dime with similar characteristics. I understand that the picture I took with my desk lamp and iPhone are not adequate to see the luster and patina, but the rim is somewhat interesting. On the obverse the rim behind “TY” and extending uninterrupted to the “1” in 1916 is noticeably raised. This same rim pattern is noticeable from the “D” in UNITED to roughly the “E” DIME. At first glance the appearance would suggest it has been cleaned, but after closer examination I cannot find any evidence of such. Maybe a dip gone wrong? Although, I suppose a dip and or cleaning would not explain the other two examples I stumbled upon unless this rim pattern is super common, and I just never noticed. Any comments and thoughts would be appreciated!  

[coinsandmedals]

Sorry for the double post. The image files were too large to post in one. Here are the images of the reverse. 

[DWLange]

The first emission of Mercury Dimes from the approved dies resulted in what the Mint calls "finning" and what the hobby usually calls "wire rim." A little tweaking of the planchet milling process addressed this problem, and it was fixed. Most new coin designs require some trial and error to get the curvature of the upset planchet just right for the press.

The finned dimes were released alongside the corrected ones, and they do have a distinctive appearance and, usually, very bold strikes.

[coinsandmedals]

1 hour ago, DWLange said:

The first emission of Mercury Dimes from the approved dies resulted in what the Mint calls "finning" and what the hobby usually calls "wire rim." A little tweaking of the planchet milling process addressed this problem, and it was fixed. Most new coin designs require some trial and error to get the curvature of the upset planchet just right for the press.

The finned dimes were released alongside the corrected ones, and they do have a distinctive appearance and, usually, very bold strikes.

Thank you for the clarification. That is pretty interesting! 

[Just Bob]

I read some time back that the first Mercury dimes were supposedly minted on overweight/thicker planchets. which accounted for the bold strike and wire rim. However, the mint had been minting dimes to the same specs since 1873, and the Mercuries were supposed to follow suit. That being the case, it never made sense to me that they would start with thicker, heavier planchets, so that explanation never seemed plausible. Mr Lange's explanation makes a lot more sense.

[Zebo]

I'll have to take a look at mine.  Thanks for mentioning this and thanks to those who offered explanations as well.

[coinsandmedals]

On 12/14/2018 at 2:26 PM, Just Bob said:

I read some time back that the first Mercury dimes were supposedly minted on overweight/thicker planchets. which accounted for the bold strike and wire rim. However, the mint had been minting dimes to the same specs since 1873, and the Mercuries were supposed to follow suit. That being the case, it never made sense to me that they would start with thicker, heavier planchets, so that explanation never seemed plausible. Mr Lange's explanation makes a lot more sense.

It seems as though that theory has been resurfacing on the internet as well. I also came across a thread claiming these were proof coins. It was an interesting read, but that theory was put to rest quickly. 

13 hours ago, Zebo said:

I'll have to take a look at mine.  Thanks for mentioning this and thanks to those who offered explanations as well.

I have always loved Mercury dimes. The first coin set I ever started consisted of Mercury dimes I pulled from junk silver. I got pretty luck with the 21s but never purchased the 16D. I’ll have to keep an eye out for these wire rim 1916 Mercurys in the future. I assume the wire rim is only found on the Ps. Please correct me if I am wrong.