Tweek,
Centralized hub doubling has not been a well-kept secret for close to a decade.
I first introduced the theory of Single-Squeeze Centralized Hub Doubling to others on usenet.collecting.coins (if you remember usenet -- you're a dinosaur!) when the 1997 Doubled Ear cent was discovered. It was more or less shrugged off then.
Then in 2006 I reintroduced the theory among my peers after Troy Watkins submitted the 2005-P Extra Tree Minnesota quarter that would ultimately open the floodgates to hundreds of other discoveries on the State and
ATB Quarters and other coins (though
DDR cents were already known for the reverse with little fanfare and no analysis).
Below is the edited reader-friendly version that I published in
Numismatic News that introduced readers to the theory:
" ... represents the virtual dead center of the coin's design. This is an important key their attribution because specialists believe they are the result of tilted hubs that were seated into proper position during hubbing.
Tilted Hub Doubling restricted to such a small area of design within the center region of the die is possible due to the result of either of two related scenarios.
1) The hub is backed off after the initial kiss of the hub into a tilted die blank and is then reset properly and hubbed again.
2) The hub and die blank are titled in relation to each other and are then forced to seat into proper position by hubbing pressure within a split second after the initial kiss of the hub into the tip of the die blank.
It must be understood that the face of a die blank (referred to as a "die block" in Mint jargon) is machined with a slightly conical configuration to aid in the flow of metal during hubbing. This would indicate that the initial kiss of a hub into a die blank would be restricted to this centralized area before continuing on to fill out the rest of the design. During this process the tip of a titled die blank would be positioned slightly off location away from the center of the hub into a different area of design than intended and thus the misplaced area of doubling on the affected die.
We have very similar effects known on several Canadian 1974 Winnipeg Centennial nickel dollars where all the doubling is restricted to the center of the die. In fact, it is ironic that the 1974 Winnepeg dollar DDR#1 and DDR#2 share the exact same design element displaced in two slightly different locations in a like manner to what we see here on our Minnesota quarter DDR#1 and DDR#2! Former Royal Canadian Mint Master Engraver, Walter Ott attributed the first one (the only one he saw first-hand) as being created in the manner described above indicating that the doubling could have been created via either of the two scenarios noted here.
With these Minnesota quarters we are well into the single-squeeze hubbing era (which was not the case with the Canada varieties in 1974) so researchers feel that the doubling would have most likely occurred when a tilted hub/die seated into proper position within the single squeeze of the hub. As the name implies, the single-squeeze hubbing procedure, impresses a complete design into a die with just one pass of the hub. The single-squeeze hubbing process was introduced to US coinage starting in Fiscal Year 1986 at which point it was used for master dies, working hubs and pilot testing for production dies. It was introduced to widespread use of production dies starting in 1997 and phased in for other dies over the next year or so with some exceptions. Prior to FY 1986, all working dies were created via the multiple hubbing process which required anywhere from two to a score or more impressions from a hub into a single die. This process required annealing (softening) of a partially completed die in between hubbings and a perfect alignment between the hub and die for all subsequent hubbings to avoid doubling. When the alignment was off for any reason, hub doubling resulted. From this process was created great numbers of doubled dies recorded by specialist up into the thousands of dies so affected, mostly minor, along with some notable wide spread varieties including the famous 1955 and 1972 doubled die cents.
In 1996 during opening ceremonies of the Denver Mint, Coin World editor Bill Gibbs was advised by an official that the single-squeeze hubbing process could produce some close spread doubled dies but that it would eliminate those of a wider spread. Shortly after, Philadelphia Mint officials took the opposite position and have continued to maintain over the years that there was no possibility of doubled dies being created at all from the single-squeeze process. They have consistently stated that none of the varieties submitted to them for examination in recent years were true doubled dies. This included the 1997 double ear cent that contains 15 areas of doubling in the central regions of the design and the 2004-P Handshake five-cent piece that displays fairly widespread doubling with classic diagnostics that many in the hobby including all the doubled die specialists and major grading services consider a diagnostic of hub doubling."
Since that time, I and many other writers have presented this information in more articles than I can count in
Numismatic News,
Coin World, CONECA's ErrorScope, NECADS, The Hub, and others.
But! I'll try to keep it a secret!
Just kidding! The cat's out of the bag but it's unbelievable how many folks are not looking.
Edited by koinpro
05/15/2015 7:35 pm
First Page
Posted 04/24/2015 3:52 pm
. But that club has taught me ALOT. A lot a lot!
