Very informative. All the recent DDO and DDR posters should look at this.
It looks like the the bounce flattens the first strike which is the giveaway to machine doubling. True DD has full rounded, not flattened, letterers and numbers, right?
@Relaxn said:
We did something like this when we were doing receptor localization studies on mice brains while I was in college. We used topographic mapping software to collate our scans... was pretty awesome!
Your images/work is impressive...
Yep. Coin collecting is quite similar to studying mouse brains -- except for the cheese part.
rmpsrpms - With appropriate narration and advance explanation, that kind of thing would really open eyes and minds in a numismatic education class. Might also help a lot with doubled dies, Simple overdates, and later undercut, filled and repunched overdates, among other things. Too bad no organization does educational grants anymore. (Central States stopped.)
I've long given up trying to monetize this work, and just do it on specific requests, such as the die doubling vs strike doubling requested in this thread, and Insider2's interesting request to use the technique for added letter detection. As I said earlier, the 3D rendering is just an adjunct to the work required for high resolution 2D imaging, so often is done "just for fun" or in the case of this thread to illustrate the capabilities of the technique...ie to see any interest. I'm happy that so many folks found the technique interesting and potentially useful.
Here are a couple more views of the 58-D strike doubling. First, a view of just the 5, cropped from the earlier 5x image, along with a side view showing the topography of the damaged letter:
And here is an image of the 95, taken with 10x objective, and an animation with a different rotational method:
PM me for coin photography equipment, or visit my website:
Fascinating! I am especially interested in the working die view, or the inverse of a coin. Reversing a coin image gives a much different perspective, essentially the same as seen from the engraver.
I have done some inverse images, but not animated. This is how the clasp of 1807 half dollars and half eagles appeared to engraver John Reich on his new designs:
Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
The die view does seem useful, especially when the characteristics of the field around the feature is of interest.
Although it is not really valid, the "die view" rendering of the strike doubled "5" is interesting looking. The die of course did not look like this, though I am not sure that could be proven with this view. I suppose lack of flow lines would be the most obvious giveaway:
PM me for coin photography equipment, or visit my website:
@rmpsrpms said:
I've long given up trying to monetize this work, and just do it on specific requests, such as the die doubling vs strike doubling requested in this thread, and Insider2's interesting request to use the technique for added letter detection. As I said earlier, the 3D rendering is just an adjunct to the work required for high resolution 2D imaging, so often is done "just for fun" or in the case of this thread to illustrate the capabilities of the technique...ie to see any interest. I'm happy that so many folks found the technique interesting and potentially useful.
Here are a couple more views of the 58-D strike doubling. First, a view of just the 5, cropped from the earlier 5x image, along with a side view showing the topography of the damaged letter:
This view, along with a similar one of a legit doubled die, will go a long way to help explain to people the difference between strike doubling and die doubling. Such a side-by-side comparison belongs in a major reference like the CPG. J.T. Stanton put out a 4 page guide to die doubling which I refer to in the Morgan dollar class I teach. While it is excellent in its own right, the low-angle views would improve it immensely, whether they're simply focus-stacked pictures taken at that angle or simulated surface renderings.
The inverted relief (die view) from the other post actually shows what a doubled die would look like were the date an incuse design element. Unnecessary in this context, though, and might confuse people.
The photo also helps show that first contact was at the thin flange to the right of the 5 and the remaining force applied normally as the planchet settled into correct position.
@Kudbegud said:
Very informative. All the recent DDO and DDR posters should look at this.
It looks like the the bounce flattens the first strike which is the giveaway to machine doubling. True DD has full rounded, not flattened, letterers and numbers, right?
Generally true. Strike doubling is caused by the field, which is fairly flat, hitting against a feature with a slight offset from normal due to die misalignment. This has the effect of making the feature appear smaller, though of course there could be some "smearing" of coin metal that causes a bit of extra widening. I think this is present on this coin but I'd need to do an overlay to be sure.
The doubling of a true doubled die (or an RPM) has the same size and shape of the feature, but is offset due to the two hubbings being misaligned. This has the effect of making the feature appear larger, and with same characteristics as the primary feature. Sometimes this looks rounded, or notched, or whatever but it always looks like a doubling of the feature, where strike doubling always looks like damaging of the feature by the die field.
PM me for coin photography equipment, or visit my website:
Help! Would one of you please go over the steps to cause machine doubling to make sure we (me too) understand as I just got confused.
So we have a normal obverse die with a "5" on it moving down to strike a normal planchet. Boom. Out comes a normal coin with no machine doubling.
Now we have the same normal obverse die moving down to strike the next normal planchet. What happens next to make this coin leave the die with machine doubling? Please be detailed. When does the strike doubling occur? Does it occur as the die goes DOWN on the planchet or as the die goes BACK UP back up after the strike?
I'm not expert enough in the 1958 minting process to give you the definitive description you request. My understanding is basic, ie that the loose obverse die would essentially "rattle" against the coin just after striking but before the coin was ejected. This is why this is considered post-strike damage rather than part of the standard minting process.
I'd welcome a more authoritative description of the orientations of the dies, etc.
PM me for coin photography equipment, or visit my website:
This has been one of the most enjoyable posts I have read in quite a while. Luckily, we had honest input and did not have a name calling event. Thanks for sharing this, rmpsrpms, you are very talented and knowledgeable in this regards. I truly appreciate your time and effort in sharing this with us.
Jim
When a man who is honestly mistaken hears the truth, he will either quit being mistaken or cease to be honest....Abraham Lincoln
Patriotism is supporting your country all the time, and your government when it deserves it.....Mark Twain
@rmpsrpms said: "I'm not expert enough in the 1958 minting process to give you the definitive description you request. My understanding is basic, ie that the loose obverse die would essentially "rattle" against the coin JUST AFTER STRIKING BUT BEFORE the coin was ejected.
This is exactly what the MInt technicians told us! The die shifted as it started to open up after the strike. One of the posts above by another member had me confused and thinking someone believed differently.
Does anyone reject the OP's explanation of "strike doubling?
Does anyone reject the OP's explanation of "strike doubling?
No rejection, but more explanation for "double profiles" seen on bust coins. The dies are set in die cups, which become loose over time. The highest part of the dies are the field, and the highest part of the obverse field is the portrait face outline because of the slightly convex die shape. The strike doubling and tripling on bust coins usually appears on the portrait face because just after the strike the obv die could shift - and the second contact will hit at the highest point.
I think that in 1812 the coins were still being individually hand-screw pressed, correct? So is this really strike doubling, as we know it from loose dies rattling in high speed presses? Or some sort of accidental second pressing? It's very cool in any case.
PM me for coin photography equipment, or visit my website:
Yes, screw presses were used until 1836. The double profiles on bust coins are widely accepted as strike doubling (machine doubling) as opposed to a double strike (two distinct strikes). They are sometimes triple profiled or even quadrupled. The mechanics are different with a modern press than a screw press, but both may be caused by loose dies.
There are examples of double strikes on bust coins which are distinctly different than "double profiles."
Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
@Nysoto said:
Yes, screw presses were used until 1836. The double profiles on bust coins are widely accepted as strike doubling (machine doubling) as opposed to a double strike (two distinct strikes). They are sometimes triple profiled or even quadrupled. The mechanics are different with a modern press than a screw press, but both may be caused by loose dies.
There are examples of double strikes on bust coins which are distinctly different than "double profiles."
So the idea that the entire bust on these coins was hubbed into the die twice (once slightly off) is incorrect.
For a toggle press the process is analogous to spinning a coin on a table. As the spin slows the coin wobbles and contacts the table round the rim - rotating. When a press is improperly set, something similar happens to the planchet as it seats in the collar. The dies suppress the planchet;s motion and cause slight, often erratic displacement during the strike time-motion profile. This can be caused by almost any loose part in the press not necessarily a die, die stake, collar flange, feeder, tension spring or any other part. It is common because it is wear-related, and easily overlooked (or maybe "accepted as normal") by inspectors. See JNR Issue #1 for patent drawings and descriptions of a typical 1895 toggle press. See From Mine to Mint for illustrations and additional description.
So the idea that the entire bust on these coins was hubbed into the die twice (once slightly off) is incorrect.
I will quote myself from a 2004 thread, I believe these comments are still correct:
Russ Logan's explanation of double profiles was the metal die cup the hammer die was placed in became worn, causing the die to shift during striking. Some years such as 1822 have no known double profiles. The years 1823, 1824, and 1825 were the most common as mintages increased during those years with apparently not enough preventative maintenance.
One thing is certain, there are 8 years in which doubling is not found in the capped series, and some die marriages within the most prevalent years are not doubled, therefore Logan's theory of lack of maintenance in certain years is correct, as doubling can be found in all die states of selected varieties in certain years. I do not know if the same applies for early copper.
The hubbing process that sinks the bust on the working die sometimes needed two or more impressions, but there is no evidence of hub doubling on bust halves as all die marriages found with machine doubling also exist without machine doubling.
Also from the thread,
"If the working die was serviced at the Mint to strengthen the bust, this would result in double (or more) profiles from this die state on. Die marriages such as 1825 O.103 show double, triple, or quadruple profiles, and also no doubling, and these occur randomly and are not tied to die state. Other doubling is not tied to die state on most die marriages."
Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
"The hubbing process that sinks the bust on the working die sometimes needed two or more impressions, but there is no evidence of hub doubling on bust halves as all die marriages found with machine doubling also exist without machine doubling."
And this is the case for the Large cents also correct?
I found my 95 DDO and shot the BE of LIBERTY at 10x. Here is the animation:
Edited to add: it's unfortunate that the strike doubling shows on the date, and doubled die on the LIBERTY, since the direct comparison of features would be best for educational purposes. I will look to see if I can find a strike doubled LIBERTY to image.
PM me for coin photography equipment, or visit my website:
Yes, it's a hit in a very interesting place. Makes this coin, or at least this view, not really suitable for educational purposes, but it's the only dramatic doubled die I own.
PM me for coin photography equipment, or visit my website:
@Kudbegud said:
Just posted
A perfect candidate for your photo magic
Would certainly be nice to see that MM in more detail, as it's a fairly dramatic repunching, but although there has been interest in the "magic" in this thread, most folks don't really seem to care.
PM me for coin photography equipment, or visit my website:
@Kudbegud said:
Just posted
A perfect candidate for your photo magic
Would certainly be nice to see that MM in more detail, as it's a fairly dramatic repunching, but although there has been interest in the "magic" in this thread, most folks don't really seem to care.
But you'd be doing it for those that do care. That's how "common practice" starts. Those who care and see the advantage slowly grow until those who don't are called "old fuddy duddiys" or "grumpy old men".
@Kudbegud said:
Just posted
A perfect candidate for your photo magic
Would certainly be nice to see that MM in more detail, as it's a fairly dramatic repunching, but although there has been interest in the "magic" in this thread, most folks don't really seem to care.
But you'd be doing it for those that do care. That's how "common practice" starts. Those who care and see the advantage slowly grow until those who don't are called "old fuddy duddiys" or "grumpy old men".
Well, I am not giving up, hence this thread. Mostly I just do these renderings for my own enjoyment, though occasionally they get used for something serious.
I put my system together specifically for documenting die varieties, and I often post on sites that are frequented by variety attributers. I've heard some interesting comments back, such as "these are great but nobody else can do this so any info gleaned isn't really valid" and "there is no more info in these than in regular 2D images". Yeah, right!
PM me for coin photography equipment, or visit my website:
Comments
Very informative. All the recent DDO and DDR posters should look at this.
It looks like the the bounce flattens the first strike which is the giveaway to machine doubling. True DD has full rounded, not flattened, letterers and numbers, right?
Yep. Coin collecting is quite similar to studying mouse brains -- except for the cheese part.
rmpsrpms - With appropriate narration and advance explanation, that kind of thing would really open eyes and minds in a numismatic education class. Might also help a lot with doubled dies, Simple overdates, and later undercut, filled and repunched overdates, among other things. Too bad no organization does educational grants anymore. (Central States stopped.)
I've long given up trying to monetize this work, and just do it on specific requests, such as the die doubling vs strike doubling requested in this thread, and Insider2's interesting request to use the technique for added letter detection. As I said earlier, the 3D rendering is just an adjunct to the work required for high resolution 2D imaging, so often is done "just for fun" or in the case of this thread to illustrate the capabilities of the technique...ie to see any interest. I'm happy that so many folks found the technique interesting and potentially useful.
Here are a couple more views of the 58-D strike doubling. First, a view of just the 5, cropped from the earlier 5x image, along with a side view showing the topography of the damaged letter:
And here is an image of the 95, taken with 10x objective, and an animation with a different rotational method:
http://macrocoins.com
Fascinating! I am especially interested in the working die view, or the inverse of a coin. Reversing a coin image gives a much different perspective, essentially the same as seen from the engraver.
I have done some inverse images, but not animated. This is how the clasp of 1807 half dollars and half eagles appeared to engraver John Reich on his new designs:
The die view does seem useful, especially when the characteristics of the field around the feature is of interest.
Although it is not really valid, the "die view" rendering of the strike doubled "5" is interesting looking. The die of course did not look like this, though I am not sure that could be proven with this view. I suppose lack of flow lines would be the most obvious giveaway:
http://macrocoins.com
This view, along with a similar one of a legit doubled die, will go a long way to help explain to people the difference between strike doubling and die doubling. Such a side-by-side comparison belongs in a major reference like the CPG. J.T. Stanton put out a 4 page guide to die doubling which I refer to in the Morgan dollar class I teach. While it is excellent in its own right, the low-angle views would improve it immensely, whether they're simply focus-stacked pictures taken at that angle or simulated surface renderings.
The inverted relief (die view) from the other post actually shows what a doubled die would look like were the date an incuse design element. Unnecessary in this context, though, and might confuse people.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
The photo also helps show that first contact was at the thin flange to the right of the 5 and the remaining force applied normally as the planchet settled into correct position.
Generally true. Strike doubling is caused by the field, which is fairly flat, hitting against a feature with a slight offset from normal due to die misalignment. This has the effect of making the feature appear smaller, though of course there could be some "smearing" of coin metal that causes a bit of extra widening. I think this is present on this coin but I'd need to do an overlay to be sure.
The doubling of a true doubled die (or an RPM) has the same size and shape of the feature, but is offset due to the two hubbings being misaligned. This has the effect of making the feature appear larger, and with same characteristics as the primary feature. Sometimes this looks rounded, or notched, or whatever but it always looks like a doubling of the feature, where strike doubling always looks like damaging of the feature by the die field.
http://macrocoins.com
@RogerB
@rmpsrpms
Help! Would one of you please go over the steps to cause machine doubling to make sure we (me too) understand as I just got confused.
So we have a normal obverse die with a "5" on it moving down to strike a normal planchet. Boom. Out comes a normal coin with no machine doubling.
Now we have the same normal obverse die moving down to strike the next normal planchet. What happens next to make this coin leave the die with machine doubling? Please be detailed. When does the strike doubling occur? Does it occur as the die goes DOWN on the planchet or as the die goes BACK UP back up after the strike?
Thanks.
I'm not expert enough in the 1958 minting process to give you the definitive description you request. My understanding is basic, ie that the loose obverse die would essentially "rattle" against the coin just after striking but before the coin was ejected. This is why this is considered post-strike damage rather than part of the standard minting process.
I'd welcome a more authoritative description of the orientations of the dies, etc.
http://macrocoins.com
This has been one of the most enjoyable posts I have read in quite a while. Luckily, we had honest input and did not have a name calling event. Thanks for sharing this, rmpsrpms, you are very talented and knowledgeable in this regards. I truly appreciate your time and effort in sharing this with us.
Jim
When a man who is honestly mistaken hears the truth, he will either quit being mistaken or cease to be honest....Abraham Lincoln
Patriotism is supporting your country all the time, and your government when it deserves it.....Mark Twain
@rmpsrpms said: "I'm not expert enough in the 1958 minting process to give you the definitive description you request. My understanding is basic, ie that the loose obverse die would essentially "rattle" against the coin JUST AFTER STRIKING BUT BEFORE the coin was ejected.
This is exactly what the MInt technicians told us! The die shifted as it started to open up after the strike. One of the posts above by another member had me confused and thinking someone believed differently.
Does anyone reject the OP's explanation of "strike doubling?
No rejection, but more explanation for "double profiles" seen on bust coins. The dies are set in die cups, which become loose over time. The highest part of the dies are the field, and the highest part of the obverse field is the portrait face outline because of the slightly convex die shape. The strike doubling and tripling on bust coins usually appears on the portrait face because just after the strike the obv die could shift - and the second contact will hit at the highest point.
Edited to link an example which illustrates this - the second contact is clearly shown to the right of the initial strike https://forums.collectors.com/discussion/543388/1812-bustie-doubled-profile
I think that in 1812 the coins were still being individually hand-screw pressed, correct? So is this really strike doubling, as we know it from loose dies rattling in high speed presses? Or some sort of accidental second pressing? It's very cool in any case.
http://macrocoins.com
Yes, screw presses were used until 1836. The double profiles on bust coins are widely accepted as strike doubling (machine doubling) as opposed to a double strike (two distinct strikes). They are sometimes triple profiled or even quadrupled. The mechanics are different with a modern press than a screw press, but both may be caused by loose dies.
There are examples of double strikes on bust coins which are distinctly different than "double profiles."
So the idea that the entire bust on these coins was hubbed into the die twice (once slightly off) is incorrect.
Good stuff Ray, you taking imaging to another level, keep it up.
For a toggle press the process is analogous to spinning a coin on a table. As the spin slows the coin wobbles and contacts the table round the rim - rotating. When a press is improperly set, something similar happens to the planchet as it seats in the collar. The dies suppress the planchet;s motion and cause slight, often erratic displacement during the strike time-motion profile. This can be caused by almost any loose part in the press not necessarily a die, die stake, collar flange, feeder, tension spring or any other part. It is common because it is wear-related, and easily overlooked (or maybe "accepted as normal") by inspectors. See JNR Issue #1 for patent drawings and descriptions of a typical 1895 toggle press. See From Mine to Mint for illustrations and additional description.
I will quote myself from a 2004 thread, I believe these comments are still correct:
Also from the thread,
"If the working die was serviced at the Mint to strengthen the bust, this would result in double (or more) profiles from this die state on. Die marriages such as 1825 O.103 show double, triple, or quadruple profiles, and also no doubling, and these occur randomly and are not tied to die state. Other doubling is not tied to die state on most die marriages."
"The hubbing process that sinks the bust on the working die sometimes needed two or more impressions, but there is no evidence of hub doubling on bust halves as all die marriages found with machine doubling also exist without machine doubling."
And this is the case for the Large cents also correct?
I found my 95 DDO and shot the BE of LIBERTY at 10x. Here is the animation:
Edited to add: it's unfortunate that the strike doubling shows on the date, and doubled die on the LIBERTY, since the direct comparison of features would be best for educational purposes. I will look to see if I can find a strike doubled LIBERTY to image.
http://macrocoins.com
Is that a scratch off the "E?" It looks raised and I've never seen that on one of these coins before. Neat.
Yes, it's a hit in a very interesting place. Makes this coin, or at least this view, not really suitable for educational purposes, but it's the only dramatic doubled die I own.
http://macrocoins.com
Just posted
A perfect candidate for your photo magic
https://forums.collectors.com/discussion/1003127/just-added-a-major-variety-to-my-washie-set-the-centerpiece#latest
Would certainly be nice to see that MM in more detail, as it's a fairly dramatic repunching, but although there has been interest in the "magic" in this thread, most folks don't really seem to care.
http://macrocoins.com
But you'd be doing it for those that do care. That's how "common practice" starts. Those who care and see the advantage slowly grow until those who don't are called "old fuddy duddiys" or "grumpy old men".
Well, I am not giving up, hence this thread. Mostly I just do these renderings for my own enjoyment, though occasionally they get used for something serious.
I put my system together specifically for documenting die varieties, and I often post on sites that are frequented by variety attributers. I've heard some interesting comments back, such as "these are great but nobody else can do this so any info gleaned isn't really valid" and "there is no more info in these than in regular 2D images". Yeah, right!
http://macrocoins.com
Well, I for one appreciate you efforts. Thanks !