difference between MDD and DD

silverandvinyl · December 14, 2002 3:40AM

Can someone explain the difference between the two so anybody without a coin education can truly understand.I'm trying to understand what the error book states.One part I just read states if the mint mark is not doubled it's a hub doubling.Is a hub doubling a DD? It's kind of complicating.Another states if it doubled on the right obverse it would be doubled on the left reverse.I'm going nuts trying to figure all this out.Would appreciate any easy to understand FD.

coppercoins · December 14, 2002 6:27AM

I'll get to a complete response later this evening, but for now, yes...hub doubling is the effect that creates doubled dies. They are in essence the same thing. Machine doubling, strike doubling, eject doubling, and machine damage doubling are also all essentially the same thing and have no collectible premium value.

I will explain how to tell the difference later, I'm running late.

coppercoins · December 14, 2002 8:19AM

Okay, now I have more time and can attempt to fully explain the difference between machine doubling and hub doubling.

Hub doubling is an effect that happened during the hubbing process of some of the dies back when the mint used the multiple hubbing process. Since the designs could not be fully impressed onto the die safely using only one design pressing (hubbing), the dies were annealed (heated) a number of times and the design was partially hubbed into the die. The die would sit to cool, and the process repeated until the design was complete. This repeated annealing gave more depth to the designs and made the dies stronger so they would last longer.

Where the hub doubling would take effect is during the re-fitting of the die onto the hubbing press. If the die was not placed in the press in exact alignment each time it was to be hubbed, the result would be a doubled design on the die - hence, "doubled die". Hub doubling is what happens to create a doubled die, so they are essentially the same thing. Because the doubling can take on different appearances depending on how the maladjustment works out, there are eight different clasifications of hub doubling. They are:

1. Class 1, rotated hub doubling
2. Class 2, distorted hub doubling
3. Class 3, design hub doubling
4. Class 4, offset hub doubling
5. Class 5, pivoted hub doubling
6. Class 6, distended hub doubling
7. Class 7, modified hub doubling
8. Class 8, tilted hub doubling

Each of these looks distinctively different from one another, especially to the trained eye. Some examples of hub doubling have characteristics of more than one class of hub doubling, thus the classes are put together with one another in numerical order to accurately describe the hub doubling exhibited by a given die. A die with distended and distorted hub doubling would be a class 2 + 6 doubled die.

Machine doubling, in it's many forms, happens when the die is not properly fitted and tightened into the minting press (the machine that makes coins). A loose die tends to bounce under the extreme force of making coins, which gives it the latitude it needs to slide slightly to one side or the other and re-hit the coin. This causes a flattened, shelf-like doubled appearance to some or all of the devices on a coin. This effect is often mistaken for hub doubling.
This photo shows a classic, typical example of machine doubling. Notice two things, especially...first, the doubling is flat, more like something smashed the letters than struck them up into a design. Secondly, notice the outlying shape of the letters, and how they are essentially the same size and thickness of "normal" letters and numbers for the given date. The reason for that is rather simple - the doubling is the effect of a second slightly off kilter strike on top of a complete, normal strike. In other words, by the time the doubling took effect, there was already a complete, normal strike on the coin which had already defined the shapes of the letters as they should be.

Back to doubled dies, remember what was just said, then take a look at this image. Notice how the doubling is not flat, it is not shelf-like, and it "appears" to be a second, complete set of devices overlapping the first. This is the classic appearance of a doubled die (this particular one is 1995P-1DO-001, the famous 1995 DDO).

Now take a look at another image. This is another example of machine doubling, but I bring it up for a point. Look at the doubling, noticing how there is no real "separation" between the devices in the doubling. They appear to be "scooted over" instead of really "doubled". There is no "notching" at the corners of the letters - void areas where the design corners of the primary letters are completely separated from the design corners of the secondary letters.

Although minor, this coin is a doubled die as well. If you look closely you can see the separation in the digits of the date, but it is more prevelant in the mint mark. Remember, however, that the mint marks on all cents dated 1990 to present were a part of the master die, and were not hand-punched as they had been in the past. What this means is that there is no such thing as a repunched mint mark since 1990. Any doubled effect on more recent coins with mint marks would have to be hub doubling, just like the 1995D-1DO-002 shown in the link.

There are different types of machine doubling. What I have shown you so far is considered "die chatter", where a loose die scoots along the surface of the coin while it is hitting the coin, creating a shelf of doubling. There is also, however, eject doubling, which looks much like plain machine doubling, except that there will be a ridge of raised metal along the edge of the doubling, indicating that the feeder arm "scooped" the coin off of the die while it was still attached. There is also strike doubling, which happens when the die lifts off of the coin and strikes it twice. The photo shows remarkable evidence of this effect in that the die scratches in the field are repeated in the doubling. Die deterioration doubling occurs as a die ages and the edges of the letters start to chip away, especially those nearer the rim where die flow is more prevelant. The photo shows an example of one of the infamous "1955 poor man's double dies" which is NOT a true hub doubled die at all.

The important thing to remember is that while there may be some collector following for the machine doubling, they are generally regarded as worthless. The main reason for this is because they cannot be counted, they cannot be cataloged. They are strictly a coin-to-coin thing, a technical error. Since error collectors generally take interest only in those errors that can be seen with the naked eye, and since these are generally not naked-eye visible, they are not collected. Doubled dies are different - they were placed into the die during the die making process, and the dies were supposedly inspected before being placed into use. ALL coins minted with a hub doubled die will exhibit the characteristics of the doubled die, making them catalogable and attributable, thus much more interesting to a much broader base of collectors.

So...I hope that's enough to bring home the difference, but I have a little quiz so you can test yourself. Look at the following images and post whether you think they are hub doubling (doubled dies) or machine doubling. I will post the answers tomorrow.

quiz image #1 - DDO, class 2
quiz image #2 - DDR, class 2
quiz image #3 - machine doubling
quiz image #4 - DDO, class 2
quiz image #5 - machine doubling
quiz image #6 - DDO, class 6

So does all this babble get me the "longest-winded post award?"

MacCoin · December 14, 2002 8:39AM

Thanx CC you are all most as good as having the book

Bulldog · December 14, 2002 9:01AM

CC,

If you are going to give such long responses, the least you could do is buy my printer cartridges....LOL Great Job!

Bulldog

coppercoins · December 14, 2002 9:14AM

The scary part for me is that I did all of that out of my head. I've explained it so many times it's like second nature to me now.

nwcs · December 14, 2002 10:24AM

Truly a wonderful lesson and great pictures! I'm not that great at identifying all the ways the mint screws up, but this was very helpful. Say, do you have on your site (I did look) picture examples of the 83 and 84 dd's for cents? I never know exactly what to look for.

shylock · December 14, 2002 10:33AM

So does all this babble get me the "longest-winded post award?"

No, you get the most comprehensive answer award -- hands down. Looks like it took Silverandvinyl a long time to get an answer here but it was obviously worth the wait!

coppercoins · December 14, 2002 10:47AM

The 1984, yes...somewhere. The 1983, I might, but I'm not sure. I'll have to try digging them out of my old backup CDs for you, unless they happen to be on the server now.

shylock - is the medal for that award made of copper? LOL!

coppercoins · December 14, 2002 11:07AM

<< <i>Say, do you have on your site (I did look) picture examples of the 83 and 84 dd's for cents? I never know exactly what to look for. >>

As for the 1983, like I thought, I don't have photos. I have nver held one of those in my own two hands, thus have had to bargain and barter to get what few photos I have had of them, which don't seem to be on the server currently.

As for the 1984 DDO, listed as 1984P-1DO-001, here it is:

image #1
image #2
image #3

And a LARGE photo that shows the whole obverse at once...

big image

nwcs · December 14, 2002 12:42PM

Thanks, CC! Just what I was looking for. I'm going to get some cents next Friday to play with over the holiday weekend and wanted to know what to look for. So is the 83 one more rare than the 84 or 95?

silverandvinyl · December 14, 2002 12:46PM

What a great explanation.Thank you very,very much.I really believe you have to be in this business for along time to understand all the terms used in most of the coin reference books.They probably are not as complicated as the books make it out to be.I will be printing out your reply.Thank you again.

coppercoins · December 14, 2002 12:59PM

I don't think the 1983 is all that much rarer than the 1984, but there are way more 1995 DDO cents out there than the other two mentioned put together. There are other very nice coins to be looking for while you're at it...

For instance, there is a rather rare, but very valuable 1995D - that's right, D mint - cent that has very nice doubling on the obverse. These little guys have been selling (when they do sell, they are rare) for figures higher than $300:

1995D-1DO-003 photo #1
1995D-1DO-003 photo #2
1995D-1DO-003 photo #3
1995D-1DO-003 photo #4
1995D-1DO-003 photo #5
1995D-1DO-003 photo #6

There is also a 1994P cent that has been receiving some attention because of a nice but weakly hubbed offset doubled die on its reverse. Specimens of this die have been selling for between $125 and $250 in BU. It's pick up point is an extra column inside the last bay of the memorial building:

1994P-1DR-001 image #1
1994P-1DR-001 image #2
1994P-1DR-001 image #3
1994P-1DR-001 image #4
1994P-1DR-001 image #5

Of course there is also the ever-elusive 1969S DDO, of which I have seen one example in my life, and it belonged to Jack Beymer. There is also an even-rarer, yet still very nice 1970S DDO that looks a lot like the 1972 DDO.

Still lots of goodies to find in change, if you're diligent.

silverandvinyl - The lesson was my pleasure. If you have questions about anything else Lincoln cent related, you can post here and I'll be glad to answer if I can, or you can send me an e-mail at your convenience. have fun!

nwcs · December 14, 2002 1:07PM

Great pics! Thank you again. I'll have fun looking through the lincolns I get next week. Still have an original bank roll of 54s that I'm soooo tempted to pick through.

How much mag do you need to authenticate the 1994 example you posted?

coppercoins · December 14, 2002 1:12PM

nwcs - As for the 1994DDR, I would think a 10X loupe should be plenty...but the "typical" magnification to use in die variety hunting is 16X. I have been usng a cheap 16X anco ($10) loupe for years at the shows, and have picked some down-right outstanding stuff over the years.

1954S contains a handful of nice looking repunched mint marks, and has one rather common but nice DDO. It's not particularly a date that a variety hunter would fall over trying to get. If it's still bank wrapped, you might be better off leaving it that way. For some reason, many of the early 50s BW rolls ended up with veining discoloration all over them, probably because of the planchet wash or problems with the alloy. The effect created is called "spider web veining" and is one of many reasons why the 1952 and 1953 Philly cent jumped in value. Good rolls are hard to find. Sealed rolls are assumed good.

Edited to add: Quiz image #4 above is one of the 1954S DDOs. It is 1954S-1DO-002, worth around $5 in BU, and that particular photo shows the typical veining problem exhibited on a lot of early 1950s cents that come from long-sealed original rolls.

Geesh, is it hard to tell I love what I do?? LOL! Get me started and I can't shut up!

Cam40 · December 14, 2002 1:15PM

1Hub Doubling(HD) class 4
2Machine or ejection doubling(MD)
3 MD deteiorating die maybe
4 HD class 1
5 see #3
6 HD class 8

coppercoins · December 15, 2002 5:18AM

TTT - Quiz answers posted next to the links to the photos.

Coindexter · May 24, 2006 9:57AM

TTT for anybody that needed this as much as I did.

difference between MDD and DD

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