I was looking for some good reads this morning and clicked on the site that got me started in coin collecting. www.conecaonline.org Until this morning I hadn't completely wrapped my head around the Single squeeze hubbing process. I knew that In the olden days they used a reduction lathe. which is why we have the major DDO's 55' 69'S, 70'S 72. The below insert is from Wexlers web site. "The Mint started using reduction lathes in 1836 to transfer designs from a master model (galvano) to the face of a master hub. These reduction lathes were pantographs with two arms. One arm traced out the design on the galvano while the other reduced it proportionately and cut it into the face of the master hub. It was a very slow and tedious process and took anywhere from a day and a half to two days to complete a master hub. In 1996 the Denver Mint opened its own Die making shop. Introducing the single squeeze press to make master dies. This was the end of the major DDO or so we thought. You can read the full article written by Ken Potter for Numismatic news on Coneca, below is what he wrote about the single Squeeze process, minus the cool pics. The United States Mint largely replaced the multiple hubbing process in recent years by the “single squeeze” restrained hubbing process. The “single squeeze” process produces doubled dies that are more often than not, restricted to the central areas of the design. 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 tilted die blank would be positioned slightly off location away from the center of the hub into a different area of design than intended. After the initial contact, the pressure of the hub would eventually seat the die blank in proper position, and in turn cause doubling on the affected die. (Below referring to 2006, 2014 and 2015 DDO's) These recent-date Lincoln cent doubled dies have been breaking the rule of centralized doubling for reasons unknown. There could be any number of reasons for this but if I had to guess based on seeing more and more of these more “classic looking” obverse doubled dies since about 2010, I’d say that some part of the tooling in the hubbing process for cents has seen some wear resulting in a sloppy fit. This could allow for a shift to occur further along into the process of hubbing a die with the shift occurring at near the finishing point of the dies’ production. No matter the cause, with the Lincoln cent doubled dies increasing in strength as we move further into this decade, readers need to keep their eyes open for them on future dates. Let us know what you find! All photos except those of the 2006 Doubled Die cent are courtesy of John Wexler; 2006 cent images by author. More on the lesser strength 2015 cent doubled dies can be found on John Wexler’s website here:http://doubleddie.com/228401.html. Ken Potter is co-author of “Strike It Rich With Pocket Change” and has penned many feature articles for “Numismatic News” and for “World Coin News.” He can be contacted via email athttp://koinpro.tripod.com/. I just wanted to add that I am thankful for this day and age, We have all the information that is needed right at our finger tips, with full pics and articles for free. Good luck Hunting!
I am probably in a minority, but since it is a single pressing on the die blank, I do not feel that a doubling effect is a 'doubled die' but machine chatter or "MD" rather than DD from multiple pressings slightly out of position. I understand why some who deal in error coins or collectors who want a 'doubled die' collection of relatively inexpensive coins would 'LOVE' to think of such as important and of high value. But as I do believe in "Collect what you want" I don't press my point to those that do , but to me these are 'machine ( die) chatter errors' . One is human error, and the other is mechanical.
Single squeeze means that there isn't multiple pressings. And wanting to call it MD, is beyond reasoning. Something is moving from start of squeeze to end of squeeze thus, causing a DDO Die.
Then something is loose/ misaligned / or out of calibration. With your analogy, every lincoln from a single master die would have exactly the same doubling, and they don't. Explain how 30-40 different doubling of even a single year lincoln is normal, THAT is the beyond reasoning part? Of course it isn't normal or every coin would have the same defect, and they don't.
I wasn't calling it normal at all, I was only specifying that something has to be moving from start to finish, other wise there couldn't be 30 - 40 different DD to a certain year.
As far as I'm concerned the 1995 DDO is the last of the true doubled dies for Lincoln cents. The modern dd's are more akin to machine doubling during die production. One reason there are so many varieties is because the single hub technique makes the dies more disposable. Therefore, less time is spent extending the dies life because of the lowered cost/increased speed of die production- just swap it out for a new one.
The Mint showed what it was capable of the years before, Since they started the copper/Zinc. Those Poor dies that they tried to save. To be short they had to cut Die life for the production of Billions of cents every year. Therefore the more variety's.
I found this on error-ref.com (putting doubled dies in the search box: http://www.error-ref.com/doubled-di...sign mismatch,of eight classes are recognized.
The 96' Is one that I have been searching for forever in early die state. I have found later die states but the smear included above in Thomas's article makes it appear as DDD.
From Pickin’ and Grinin’ From wexlers website “These recent-date Lincoln cent doubled dies have been breaking the rule of centralized doubling for reasons unknown. There could be any number of reasons for this but if I had to guess based on seeing more and more of these more “classic looking” obverse doubled dies since about 2010, I’d say that some part of the tooling in the hubbing process for cents has seen some wear resulting in a sloppy fit. This could allow for a shift to occur further along into the process of hubbing a die with the shift occurring at near the finishing point of the dies’ production.” - reasons unknown is what gets to me and we are still in the new era of the die designs for shields the lower relief and composition I’m sure on the future we’ll have much more on this subject a better understanding of doubled dies or “doubled dies” on shield cents
Let's blow this thread wide open . We know class 9 and 10 is made from the single squeeze hubbing process ( center doubling ) . So, could anyone tell me why there other classifications of double dies from single squeeze hubbing . Remember only class 9 and 10 supposed to be from single squeeze hubbing . Why is there other classifications of Doubling . This should be interesting . As Ken Potter would say they have no ideal what's going on . Oh yeah don't wanna forget the head-scratching too that comes along with single squeeze hubbing .
I would assume that as the hub is slightly convex, and can meet the die not square until the pressure corrects it's position, leading to the centre doubling, the same should then apply to a badly installed hub which is tilted. This will initially contact the die further away from centre as well and lead to doubling towards the outer edges, although these would still be classed as 9 or 10. But what if the master or working hub was doubled?
