1970 S Proof RPM or MD

[viaduct]

Hi all – New to the forum and been lurking and learning. I ran across this 70 S Proof Lincoln and wanted to know if it is RPM or just MD. It looks like MD but not sure if MD happen on proofs also. This is a great forum and I am trying to learn from it. THX Ed

[wavysteps]

I believe that I can see doubling on the date, so that would make it machine doubling seen on both the mintmark and the date.

BJ Neff

[viaduct]

Thank You Mr. Neff. So Proof coins also can have machine doubling. THX Ed

[wavysteps]

Machine doubling can appear on both business and proof struck coins. Error-ref.com has this pertaining to the subject:

http://error-ref.com/machine-doubling-.html

BJ Neff

[viaduct]

Thanks - Will check it out Ed

[jcuve]

Thank You Mr. Neff. So Proof coins also can have machine doubling. THX Ed

Proof coins, more often than not, do have some machine doubling. Hub doubling on proof will show up more as notched corners or splits with subtle, still rounded separation lines. MD is often mild, and retains the cameo frosting, which makes it very deceptive at times.

Below is 1970S DDO-006 - 1DO-028P. A minor class I proof DDO. Greenish arrows show separation lines and minor splits. Black arrows show MD.

[viaduct]

Thanks Jason for the help - also Mr. Neff 's link hepled alot. I understand MD and now know it can happen in many ways. THX Ed

[19Lyds]

It looks like MD but not sure if MD happen on proofs also.

Since Proof coins are stuck "at least" two times and sometimes three times, there is a greater possibility of MD for proofs than there are for business strikes.

[diamond]

The likelihood of machine doubling is theoretically the same in business strikes and proof strikes. The number of strikes is irrelevant, as machine doubling does not reflect the presence of an additional strike. What IS more likely in a proof is the presence of imperfectly aligned strikes, otherwise known as flat field doubling.

[19Lyds]

The likelihood of machine doubling is theoretically the same in business strikes and proof strikes. The number of strikes is irrelevant, as machine doubling does not reflect the presence of an additional strike. What IS more likely in a proof is the presence of imperfectly aligned strikes, otherwise known as flat field doubling.

But, would you not agree that the more times the die comes in contact with the coin that there's more of a likely hood of MD?

I only say this because FF Doubling AND MD is rampant on Silver Proof IKE's.

[diamond]

Since machine doubling appears as the result of a loose die, loose die assembly, vibrating press frame, etc., a single strike is all that is needed to document the problem. But I suppose if the problem is intermittent, a succession of strikes will raise the odds that the instability will appear within the sequence of strikes. So your original claim does have some validity.

[19Lyds]

Since machine doubling appears as the result of a loose die, loose die assembly, vibrating press frame, etc., a single strike is all that is needed to document the problem. But I suppose if the problem is intermittent, a succession of strikes will raise the odds that the instability will appear within the sequence of strikes. So your original claim does have some validity.

Thank You Mike.

[wavysteps]

Actually the hammer die comes in contact with the planchet only once during a proof striking. The initial strike is made by the hammer die, which then stays on top of the struck coin. A ram then strikes the hammer die again producing the sharp relief found on proof coins.

BJ Neff

[diamond]

I have seen videos of presses striking proof coins, and they showed two downstrokes of the hammer die. I suppose there is variability in the methods used to strike proofs, depending on the press brand and model.

[viaduct]

Wow - so much info from the experts - thanks for the education. I hope to learn but need to read and listen more. THX Ed