1976D Kennedy Half Dollar Bicentennial Fingerprint Struck on Reverse

[wk113]

I have, what I believe to be an interesting occurrence of a finger or thumbprint that was inadvertently left during the making of the Reverse die for this 1976D Kennedy Half Dollar Bicentennial. This print can be seen on both sides of the tower as well as between the pillars and also bisecting through the pillars. It appears to be a thumbprint and I am very curious if this has been seen before. I have seen how the dies are made for coin production today and am curious to know how the process differed during the 1970's which may have paved the way for an error like this to occur. Further considering the wearing effect the coin minting process has on the dies, I am also curious how long a print like this could last on the die and how many other coins there may be just like this one. I am, as well, very curious to know who's print this is and suspect that the BEP may have this print on file from one of their employees who worked in the die making division in the early 1970's. It would be an incredible project to discover who left this print for me to find almost 50 years after it was left immortalized on the back of a Bicentennial Kennedy Half Dollar. I am absolutely curious as to your thoughts on this and any information you may have. I hope the photos are clear enough for you to see what I see. Thank you so much for checking out this gem and taking the time to share your thoughts.

[Ronald]

I believe this was posted once before, or one very similar.
I am curious, you seem very certain it is a mint thumbprint, what would be your way of verifying this and have you made any attempt other than wanting these folks to do the research for you?


I searched mint fingerprints and found it was not a Kennedy half, but a lincoln cent posted by Anita 9/22.
But similar in theory.

[wk113]

Ronald,

Thank you for your reply. Curious enough, as I was searching my pennies today, I also found a penny with a fingerprint. There is a distinct difference in the two examples: the penny is flat where the print exists and is clearly where the finger oils affected the surface of the penny. Thank you for the heads up on Anita's post. I will check it out and see what she found. On the half dollar, the ridges of the print can be felt as high and low points if you run your fingernail across it. Also, the way the print is both behind as well as bisecting the pillars of the tower seem to indicate that the print is indeed part of the coin itself.

On other methods of verification, to date, I have searched online for other examples of this and have yet to find anything that matches and thought I would join this forum and post it here as my first post. I have other coins I will be posting as well but on this particular half dollar, I am considering contacting the college in our area to see if they might be interested in looking at the coin under their magnification equipment and am hoping that there is someone I can speak with that may be able to actually measure the surface anomalies. It would be amazing to be able to visit a fingerprint specialist that may be able to digitally map the print. I will certainly post any of these findings here as they become available.

Thanks again for your reply.

[Ronald]

If you believe it was done during the minting process, would it be safe to assume there must be many, many others? With the same print?

[wk113]

I do believe that there would be others. With a population of 287,565,248 from the Denver Mint, I assume there are others though I am quite curious as to how the striking process may affect the shallow ridges of the fingerprint as part of the die. We know that the dies are polished to get more life out of them and during that polishing process, fine details are lost as in the 1972D Kennedy Half Dollar "No FG". What I don't know is how many strikes are made before a polish is conducted. It may be safe to assume that this print error would have been near to a First Strike condition and the print may have continued for several hundred if not thousands of coins. With the bisecting of the pillars being a part of this particular example, it would be assumed that the interrupted pillar condition would have continued for many strikes after the print faded and that the separations of the pillars would have increased in severity as the die received it's subsequent polishes. I have now reached out to a company that does Non-Contact Profilometry as well as reaching out to my local university science department to see if there are any possibilities of having this coin scanned. Updates will follow as they are available.

[Ronald]

I am curious to see response from others, maybe on what kind of caustic material/acid a mint worker could possibly have on their fingers that would render a hardened steel die with a new detail engraved in/ on it of a finger print. I wonder what the mint worker’s finger looked like.

[PNWMAKES]

Post mint finger print not from a mint worker touching the die. In my opinion.

[wk113]

Update: I want to thank everyone who replied to this post. Your views of the situation are very helpful in assisting me to continue on the search for the most likely answer to these questions. After a bit of additional research on the die making process as well as having purchased a new digital microscope, I have determined that the fingerprint is most likely the result of Post Mint Damage. It appears that there was a caustic reaction between the nickel alloy of the coin and the chemical composition of the oil contained on the fingerprint which has resulted in the nickel alloy being degraded at the points of contact. This degradation has resulted in the high points of the finger print causing low points on the coin. I have found additional examples of other denominations that exhibit similar characteristics and have used them as further support of this revised opinion of what is on this coin. It is, no doubt, a great asset to have this forum available to discuss these irregularities in an effort to determine what is truly a unique find or simply a coin that has had an interesting post-mint life. Thank you all again for your time. May the hunt continue!

[Ronald]

Update: I want to thank everyone who replied to this post. Your views of the situation are very helpful in assisting me to continue on the search for the most likely answer to these questions. After a bit of additional research on the die making process as well as having purchased a new digital microscope, I have determined that the fingerprint is most likely the result of Post Mint Damage. It appears that there was a caustic reaction between the nickel alloy of the coin and the chemical composition of the oil contained on the fingerprint which has resulted in the nickel alloy being degraded at the points of contact. This degradation has resulted in the high points of the finger print causing low points on the coin. I have found additional examples of other denominations that exhibit similar characteristics and have used them as further support of this revised opinion of what is on this coin. It is, no doubt, a great asset to have this forum available to discuss these irregularities in an effort to determine what is truly a unique find or simply a coin that has had an interesting post-mint life. Thank you all again for your time. May the hunt continue!

Good luck in your endeavors. I have seen many finger printed coins through the years and have come to the determination that you never know what someone is using to fix/hold a coin with to their preference of holder. Two sided tape, wood glue, packaging tape, superglue, silicone etc and how finger prints could vary to other coins while enjoying their way of collecting. Have fun