An Proof Halve 1983 MM made me crazy

silviosi

Hi, it is not my coin. I post here to have some opinions. It is proof 1983 Halve perfect the rest except this alien MM. If is an MDD why nothing was touch? Any suggestion or opinion is welcome. Your point of view.

ricko

Looks like machine quadrupling..... Cheers, RickO

acloco

Any double/triple/quadrupling on any other areas?

Could be a repunched mint mark???

wozymodo

Curious ...

BuffaloIronTail

Excuse my ignorance, but isn't that an upside down mintmark?
I'm still trying to figure out this mintmark from a 1968-S Proof:

Pete

silviosi

The MM it is not up-side down is as coin it is.

The lines in the photo as "wozymodo" marks are from the package.

ricko
Looks like machine quadrupling..... Cheers, RickO

Is first time I see this on a coin. Interesting One strike one bounce and second strike another bounce.
For me still the mystery why others parts of the coin was not touch by those bounces.

Steven59

@silviosi said

One strike one bounce and second strike another bounce.

For me still the mystery why others parts of the coin was not touch by those bounces.

Same thing I always asked about normal MD - why one area of the coin (or just one letter) instead of the whole Obverse or Reverse - so far nobody has given a good reply to why that happens.

Shane6596

Possibly die skidding....

"The hammer die is designed to move vertically during its downstroke (which culminates in the strike) and during its retraction phase. Horizontal movements are undesirable and can leave behind a host of errors.

Horizontal movements can occur before impact, during impact, and during retraction. If a lateral shift occurs during impact or early in retraction (before it’s cleared the coin’s surface), the die will drag itself across the coin. This will cause the newly struck design to be repositioned, smeared, scraped or erased. Effects will also vary depending on whether the movement occurs in the course of a single strike or during a second strike."

silviosi

@ Steven59 said
Same thing I always asked about normal MD - why one area of the coin (or just one letter) instead of the whole Obverse or Reverse - so far nobody has given a good reply to why that happens.

@ Shane6596

Thanks for this explanation.

NOW: I agree with Steven59 and I will explain this.:
From point of view of physic, only one letter to has Mechanical Doubling or Machine Doubling it is against all the physical laws know at this point as per today. I can agree that have Strike Doubling on one letter is possible because this kind is due to the Die aging.

Please think that the Hammer strike for example at 180 tones. We have the planchet as sandwich between the Hammer and the Anvil. The anvil move also and has the propriety to imprint the design and also a big role to absorb the forces and dissipate. I had some folks which told me the anvil do mot move, Not true. If do not move the planchet will have molecular failures.

The forces of the strike from the hammer will will dissipate 90 Deg. with the flow of the material (meddle to sides) and 180 Deg. on the Anvil's absorption of the forces.

Take all those factors in consideration, if the planchet move, the second strike must live marks theoretical on both sides of the new coin.

I will not wrote a study for this because I have others studies to finish and I do not have a horizontal and a vertical press to be able to perform a studies. Then i will do for what? Long time ago I pass the 300 studies on Accademia, I need another one? No, just coins, Notes, Stamps, Artifacts and quiet retirement (If my wife let this quiet!!!).