Extreme example of strike doubling

[GarryN]

Everyone, take a look at this picture, if you would. The poster, who I understand is a grader at ANACS, described this as extreme strike doubling of a mintmark. The question is: is this really strike doubling? If it is, how does this occur on a mint mark only?


http://www.vamworld.com/message/view/home/16659575

[Bob P]

There is a tiny bit of machine doubling on the ribbon above and to the left. Sometimes, if a mint mark was heavily punched into the die, it means the relief on the struck coin is a bit higher, and is susceptible to doubling during the strike. Machine doubling may also be ejection related. Although it is really difficult to say exactly why only this area was affected, it is not a rare occurrence, and there is little doubt it is machine doubling. No diagnosis would be able to confirm it as an RPM, nor would a subsequent 2nd strike cause this anomaly.

[GarryN]

Thanks Bob ! Do you mind if I ask that question out there?

[Bob P]

I don't mind at all Garry.

[wavysteps2003]

One thing to remember is that we are working with a curved surface. It is possible to get isolated machine doubling like this because of the curvature of the working die.

While many pass by the mechanical doubling as an after mint defect there are a few of us who see more to it than most think it is

To be honest with you, I am fascinated with the multiple (3 or more) machine doublings. If you start delving into how this happens your head will start spinning.

BJ Neff

[GarryN]

You were correct Bob, was there any doubt? If you look at the thread, I gave you credit for the solution.

Gar

[Dick]

GarryN, I would make mention of the fact, which follows BJ's comments. The Canadian coins are, ( the ones with MDD), do have a premium, as opposed to ours, unless it is very outstanding, does not. I have several cets with machine doubling. It looks very much like thedie doubling, but still has th shelf.
Dick

[GarryN]

I try not to post too much on vamworld.

[GarryN]

B J, my head is spinning just contemplating how that mint mark was machine doubled. That's the most interesting machine doubling example I have seen. Others are not so appealing. It seems that descriptions of doubled devices in Morgans more often than not are referring to machine doubling. Very few doubled dies in Morgan Dollars. The most well known being the 1888-O Hotlips.

[wavysteps2003]

Garry, I have always maintained that ALL multiple hubbed dies are doubled dies; it is the degree of magnification needed to see the doubling that we base our findings on.

As to the machine doubling on the mint mark, it is indeed odd. However, we are left with little choice as to what did happen. One or both of the dies were a bit loose, which can cause chatter on the struck coin. It just so happened that the point of contact was the mint mark on the coin. I have seen isolated machine doubling on other coins and it has always seemed a bit weird.

Here is one explanation. When the mint mark is punched into the die, the force of the punch may leave a small indent on the die surface where the mint mark was placed. This would equate to the mint mark and a small portion of the field around the mint mark being slightly above the surrounding design elements. This would subject the mint mark to be the first thing struck (and maybe the only thing struck) on the bounce (machine doubling) since it is the highest object on the coin.

Can we see this increase in height on the coin in this area? Not likely since we are working in extremely small differences in height.

As to the other isolated machine doublings that I have seen; most do involve the mint mark.

BJ Neff

[GarryN]

I agree, but machine or strike doubling is not a multiple hub doubled die from what I understand. Is that correct?

[wavysteps2003]

That is correct; a doubled die or hub doubling is not and should not be confused with machine doubling. Hub doubling is connected to the making of a die (or hub), while machine doubling is an after strike occurrence.

BJ Neff

[GarryN]

That's what I thought.. see I am starting to understand things.

[Dick]

Garry, maybe this will help. I tried to explain something, but after posting, I couldnt make sense of it and deleted it!
What I wanted to say is, the Master hub makes the working hub, and the working hub makes the working DIE. If there is any HUB-Doubling present on the hub, it will be transferred to the working Die. All coins made by this die will carry all "m,arkings" on the die.
In the case where there is no hub-doubling, then you have a different set of rules, that apply.
When the working dies are not set properly. If one is slightly loose, it will chatter, and this micro-movement will cause LATERAL pisplacement of the higher metal in the point(S) of contact. This is what we refer to as Machine-doubling. It is always flat, and when looked at with the imagination working, to place the shelf back under the device, it will be no wider that it was meant to be. The next, and progressive coins will only show what the die was meant to show, when properly set.
Dick

[Bob P]

A very educational piece this has turned out to be. Wouldn't you agree?
Thanks for the credit at VAMworld Garry. There always is a doubt when we talk about trying to determine what causes an anomaly. Unless you are there to see it happen, then that little bit of doubt will always exist.