1970 D Kennedy Half variety? Pic added.

ormandh

Is there a DDR for the 1970 D Kennedy? I have one that is still in the cello that appears to have doubling on the "TES OF AMERICA." Any ideas if this is a common occurance? -Dan

cladking

Yes. There are a couple of DDR's that show up in the mint set if memory serves. The better
(yet more common) has the USA as a pick up point. There are also a lot of machine doubled
coins that look something like it though.

cladking

This appears to be mechanical doubling.

There are four listed DDR's in Wile's "The Kennedy Half Dollar Book".

BuffaloIronTail

I believe it to be strike doubling.

Pete

koynekwest

A good example of machine doubling.

coppercoins

Definitely machine doubling - no question about it.

LastExitInNY

I have to plead ignorance here. Can someone explain the diffs in doubling ? Thanks

cladking

Hubs used to be pressed into the dies multiple times to get the design transferred to
the dies. Sometimes something would shift in between impressions so that the die
would have a doubling (visable parts of various impressions).

Mechanical doubling (also known as strike, ejection, machine doubling) is caused by various
problems which occur as a normal die is coming away from a newly struck coin or when the
coin is ejected from the coining chamber. It is believed by some that most of these are caused
by vibration of the press. There is also an effect known as die erosion doubling which is often
seen on highly eroded dies and is caused by the wear of striking many planchets.

Normally only the dies with doubling are in great demand and are usually scarce or uncommon.
Many modern examples are rare.

Otherwise doubled coins can also be rare but there are few who collect such coins.

LastExitInNY

Thanks Cladking, that explanation really helped! Now if only I could ever tell the difference.

cladking

Ususally it's not difficult to tell with the coin in hand. Mechanically doubled coins always
have the secondary image flat and shelf-like. Where fine detail appears such as serifs
these to will have a scraped appearance rather than true doubling.

Die erosion doubling will not look shelf like but should be suspected anytime there is ex-
cessive die wear on a coin.