A 1962 proof quarter with strike doubling. OK. So it's not "strike doubling." It's doubling from an offset second strike. The obverse die moved a little between strikes. This is fairly common on proof quarters from this period, but this one is a bit extreme. Notice the small area of pitting in the field on the right side of the 'Y'. It is also doubled.
Great example,, Do You consider these to be Errors? I know that there is a split of opinions on this type of doubling.
Yes. This is actually a mint error, an imperfect strike. Multiple strikes are supposed to land in exactly the same spot as the previous strike(s), but this obverse die shifted between strikes. This is similar to one of the ways a doubled die is produced when shifting of the master die occurs between impressions when creating a working die. This is different than ejection doubling or mechanical doubling, as that occurs after the coin has been struck for the final time. Rule of thumb, just about any anomaly with the planchet, die, or strike can be considered an error. Anything after the final strike is damage, not an error. Ejection doubling or mechanical doubling occurs a fraction of a second after the final strike, so it is considered damage to the already struck coin.
OK, so apparently "Strike Doubling", "Ejection Doubling", and "Mechanical Doubling" are all considered to be the same thing according to the Doubled Die monologue. To be more precise, this coin would be an 'offset' second strike, causing flat field doubling along the edge of the devices pressed back into the field by the offset second strike, and device doubling at the opposite edge of the device showing as a partial raised device from the later strike. WHEW! Apparently, strike doubling occurs after the strike, so this coin exhibits doubling from an offset second strike.
Well if you split the time down to nanoseconds I suppose it could be considered after the strike in some cases. Mechanical doubling is my preferred term - for it occurs at the moment of the strike. When the hammer die strikes the planchet - something moves slightly and allows the dies or the planchet to shift ever so slightly which is what causes the doubling effect. Those who call it ejection doubling are also correct in some cases - but again this occurs at the moment that the dies begin to separate but are still in contact with the planchet. Again something shifts causing the doubling effect. But in any case or with whatever name you choose to use - the dies must still be in contact with the planchet for a fraction of a second in order for the effect to happen. Otherwise - it cannot happen.
There are definitely 2 schools of thought on this issue. I tend to go with the assumption that the strike/minting process is finished when the die is no longer pressing metal from the blank into the die's design cavities and starts to pull away from the struck coin. Any movement of the die while it is still striking/pressing metal into the design cavities will not show mechanical doubling on the struck coin. Only after the striking is completed and there is additional incidental contact between the die and struck coin can mechanical/ejection doubling occur.
You are correct - it can occur that way. But it can also occur at the beginning moments of the strike as I reported below. When the hammer die strikes the planchet - something moves slightly and allows the dies or the planchet to shift ever so slightly which is what causes the doubling effect. Imagine this if you will - that the hammer die or the anvil die is not seated correctly. So when strike pressure begins one the dies shifts slightly as more pressure is applied. This shifting or twisting of the dies creates the doubling. All of this from beginning, while the dies are still completely apart - to end, when the dies are once again completely separated - takes place in less than 1 second. And the effect of what we call mechanical doubling can occur at any point in that time frame. It can be at the start - it can be at the end or it can be in the middle. But in any case - the effect is caused by something moving during the strike. That's all that really matters.
Wouldn't any doubling created at the beginning or intermediate stages of a strike be obliterated as the strike progresses? Before the strike, the planchet is blank. At the beginning of the strike, the die touches the planchet and begins to impart design elements. If die movement/doubling occurs at this time, wouldn't it be obliterated as the doubled portion is pressed further up into the die's design cavity as the striking progresses? If the die moved while at the peak of striking pressure, there couldn't be any mechanical doubling because the entire raised portion the coin's surface would be pressed into the die cavities and would only move along with the die, showing no doubling. Only after the strike is complete and the die starts to move away from the struck coin could there be any contact between the die and struck coin that would produce mechanical doubling...???
No - not really. Take for example and overstruck coin. It is quite common to still be able to see the design details of the original coin underneath the new overstrike. I know that's not the same - but the end effects created by the overstrike are. One still came before the other. I understand what you are saying - but that's just not how it always works.
Thanks, GD, for sharing your insights and for your patience! I think an overstrike is a fine example of what we are discussing, with the overstrike being the additional incidental contact between a die and an already struck coin, producing doubling. The only difference is the minting process would be extended past the first strike to the end of the overstrike, so everything that occurs to the coin between these strikes would be a legitimate mint error instead of damage. It's beginning to sound like we are saying the same thing.
