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1971-D Silver Kennedy

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Pillar of the Community
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 Posted 06/23/2009  6:26 pm  Show Profile   Bookmark this reply Add ratman4762 to your friends list
If indeed it is a silver clad, then you would have a rare one. I'd first weigh it. silver clad weighs 11.5 grams, clad 11.3 grams.
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 Posted 06/23/2009  6:35 pm  Show Profile   Bookmark this reply Add Gilbert to your friends list
I have done the tissue test and the ring test and in both cases it acts as if it is silver. I have not weighed it yet because I'm not sure what it should weigh, being punched from quarter stock. Any ideas on what I could calculate the weight? Also is a quarter and half blank the same size as the finished coin? If they are I could calculate what the weight should be.
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 Posted 06/23/2009  6:51 pm  Show Profile   Bookmark this reply Add ratman4762 to your friends list

Quote:
The second thing I would do is weigh the suspect coin and compare to the known weights for Kennedy half dollars: silver (both 90% and 40% clad versions) are 12.5 grams,
90% are 12.5 grams, 40% are 11.5 grams, clad are 11.3 grams
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 Posted 06/23/2009  8:22 pm  Show Profile   Bookmark this reply Add Conder101 to your friends list
Unfortunately weight is not sufficient to tell a silver clad from a coppernickel clad. A coppernickel clad weighs 11.34 grams but has a tolerance range of .45 grams So it can weigh anywhere from 10.89 grams to 11.79 grams. The silver clad weighs 11.5 grams but also has a .4 gram tolerance. So a silver clad half can weigh anywhere from 11.1 to 11.9 grams. So a coin whose weight falls in the 11.1 to 11.79 grams range could be either one.

You say it passes the tissue test. Then next I would check the edge to see if you can see the center copper or copper/silver core. This is to make sure it isn't a regular coin that has been silver plated.

If the core is visible then it needs to have a specific gravity test run on it. That test will be difinitive because the copper nickel clad has a specific gravity of 8.92 while the silver clad is 9.53 A properly conducted SG test may givee you results that vary from these figures by a few digits in the hundredths place, it will NOT vary by .6

And you don't need to concern yourself with what the weight of a half dollar struck on quarter stock would be, because the quarter stock was all coppernickel just the same as the half dollar stock. The way the 1971-D silver clad halves would have come about was from left over 1970 planchets accidently getting mixed in with the coppernickel planchets. These would have either been left over blanks from striking the 1970-D halves for the mintsets, or rejected proof planchets that were sent to Denver by mistake. (Rejected coppernickel clad proof blanks were routinely sent to Denver, but the 40% silver blanks should not have been. Rejected 40% silver blanks shipped to Denver were how the 1974-D and 1977-D silver Ikes were created and how the 1977-D silver half dollar was created.)

Fankly I supect the note in the RedBook about the 1971-D 40% silver half is a typo. I was not aware of any 1971-D 40%ers, but 1974-D's do exist and they are not mentioned.
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 Posted 06/23/2009  9:39 pm  Show Profile   Bookmark this reply Add Morgans Dad to your friends list
Conder101, Thanks for the great informative reply, (as usual) You have a great understanding of the Numismatic world and it is a pleasure to follow your educational reply, Thanks again, Mike.....
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 Posted 06/24/2009  10:32 am  Show Profile   Bookmark this reply Add Gilbert to your friends list
Thanks for your input! So if I'm getting this right, there are no 1971-D silver Kennedy's and it would not be worth my $ to send it to PCGS? Thanks again.
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 Posted 06/24/2009  10:55 am  Show Profile   Bookmark this reply Add nod2003 to your friends list
No regular silver 1971-D halves. If your coin is truly silver (not just the result of someone plating it), then it could be a rather valuable error.
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 Posted 06/24/2009  11:07 am  Show Profile   Bookmark this reply Add jbuck to your friends list

Quote:
90% are 12.5 grams, 40% are 11.5 grams, clad are 11.3 grams
Ooops!

The CCF Kennedy half dollar Coin Facts page is wrong.

I thought I remembered the 40% clad and Cu-Ni clad being closer in weight, but I did not have my Red Book with me at work to double check. Must remember to verify, verify, and verify!
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 Posted 06/24/2009  11:14 am  Show Profile   Bookmark this reply Add bobby131313 to your friends list
Fixed
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Bedrock of the Community
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 Posted 06/24/2009  12:22 pm  Show Profile   Bookmark this reply Add Conder101 to your friends list

Quote:
So if I'm getting this right, there are no 1971-D silver Kennedy's and it would not be worth my $ to send it to PCGS?

I don't know of any 71-D 40% silver halves. That does not mean that one can't exist, they don't need my permission. But as I said check the edge and if it does show the "sandwich" structure but passes the tissue test get a specific gravity test done on it. If you can find someone close by that can do it, of if you have the right equipment you can do it yourself and it should cost little or nothing. If SG says it is 40% silver THEN it would be worthwhile to send to a TPG. I've never been a big fan of sending money off to the TPG's if you don't have to. If you can run your own tests at no cost and if they prove it can't be silver, you've saved yourself 30 to 70 dollars and weeks of time for the TPG to tell you the same thing.
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 Posted 06/24/2009  1:20 pm  Show Profile   Bookmark this reply Add Gilbert to your friends list
Thanks to you all. I will check into the SG test.
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 Posted 06/24/2009  1:43 pm  Show Profile   Bookmark this reply Add gettingbrowned to your friends list
Here's an idea:

Contact a local high school, and see if maybe an advanced chemistry class could use your half as a learning experience on specific gravity.

Bring in a silver half, a silver clad half, and the mystery coin... and watch the students' surprise when they learn that chemistry can have applications in "real" life. :D

Just an idea!
Edited by gettingbrowned
06/24/2009 1:43 pm
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 Posted 06/24/2009  2:11 pm  Show Profile   Bookmark this reply Add jbuck to your friends list

Quote:
Here's an idea: Contact a local high school...
That is a very good idea!
Edited by jbuck
06/24/2009 2:12 pm
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 Posted 06/24/2009  4:50 pm  Show Profile   Bookmark this reply Add Elimist to your friends list
Normally I would have to say that the owner of this coin is somehow mistaken and what he has is something other than a silver '71-D Kennedy half.


But......

I have glowing memories of the time a person came onto this forum to ask what we knew about this silver 1970 quarter he had. The community promptly told him he was off his rocker and it caused soo much controversy on the forum that Bobby and Susan Personally went to the owner of this quarter and inspected it themselves. And sure enough.....it was a silver 1970 quarter. I never heard much about that quarter after the thread was locked. Maybe Bobby can enlighten me?
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