2007 P SMS SAC - Double Struck or MDD?

[Russellhome]

I found this in a 2007 mint set I just received. The doubling is extreme near the rim and disappears toward the center of the coin. Both sides have the same extreme doubling - like the entire planchet rotated between strikes. Would this be a case of massive MDD or would it qualify as Double Struck?













And it did a number on the incused designer initials... SS became SS SS.



It may be MDD -- but it is pretty darn interesting.
[edited 10-19-07 to include better photos]

[eagames]

Yes, it's not a doubled die but it's neat.

[mikediamond]

Puzzling. It's very unusual to have machine doubling on both faces. It's even more unusual to show it to the same extent and in the same direction on both faces. That's what you'd expect of a double-strike, but it really doesn't look like a double-strike. It doesn't show the sharp but incomplete penetration of the first strike through the second. On the reverse (the face struck by the anvil die in this case), your coin seems to show the typical marginal shelving of MDD. On the obverse the doubling is much more rounded and resembles a doubled die. The full separation of the designer's initials is impressive.

Whatever it is, it's mighty unusual.

[Dick]

I was going to respond, but Mike beat me to the draw!
I agree, with the general consensus, it is MD, but a very impressive result. It is one that Coop would set aside for "educational" purposes.
Dick

[Russellhome]

Yes - this one gets so bad that looks good. It certainly got my attention.

Months ago, I found a Kasas quarter with MDD nearly as severe as this SAC. I didn'd bother keeping that coin -- but I did do a photo or two. If I recall correctly, it only showed the massive MDD on the KANAS letters -- and it was normal on the flip side of the coin.



Billy Crawford shows a more extreme MDD example of the 2005 Kansas quarter in his DVN issue #7. On that example, the MDD on the 'KANSAS' letters was just about the same as on this Sac dollar. MDD existed on the entire reverse -- but was much weaker the further south on the design. Also - the MDD on that coin was liniar - all from right to left. On this Sac, the MDD is fairly even on all outer lettering and moves in a circle around the coin - clockwise on the reverse and counter-clockwise on the obverse.

This SAC is definitly an interesting example of MDD. I think I'll keep this one just for the fun of it.

[Gabe]

Wow.. the obverse doubling looks like very a very strong doubled die, especially in the designer initials.

Is the concensous is that the coin shows MD?

[Russellhome]

The designer initials are not raised letters - they are incused into the coin. So the normal 'rules' don't apply. Many of the State Quarters have incused letters -- and where significant MDD is present, the incused letters get the characteristics of true die doubling (i.e. notching/separation). The VDB on those massive strike doubled 1969 cents does the same thing - as it too is incused lettering.

MDD on SACs is fairly common - and the SS initials will often look like they are slightly doubled. But this coin with full separation of each S is by far the most extreme example I've seen.

[coppercoins]

I believe it to be a very well positioned double struck in collar...one that would be considered pretty valuable in my book. I really like it. Machine doubling isn't usually ever so complete and so even.

[Russellhome]

[mikediamond]

I have to disagree with Chuck. The doubling of LIBERTY shows none of the characteristics of an in-collar double-strike. You see none of the expected sharp and incomplete penetration of the first strike through the second strike. The doubling on the reverse face resembles machine doubling more than it does a double-strike. I think it is a rare case of two-sided machine doubling. I know of no other form of doubling that would function as an alternative candidate.

[coppercoins]

And I'm no error expert - so take it for what it's worth. It's no case of typical machine doubling, though.

[mikediamond]

I agree, it's very unusual. I've only seen a few examples of two-sided machine doubling. One was on a Sac dollar. I'm not exactly sure how it's produced, as all of the traditional explanations apply to one-sided doubling. Despite not being a double-strike, it's still a fascinating error. I'm an enthusiastic collector of extreme machine doubling and have written a number of articles about it. This is the kind of coin I'd happily spend $100 for.

Would you mind if I borrowed it so I could write an article about it for Errorscope? Your photos are excellent, so I'd probably use those. Naturally, you'll be fully credited. I mainly want to borrow the coin to get a better sense of its 3-dimensional topography.

[Russellhome]

Mike

Sure - I can send it to you. Shall I send it to the PO Box address listed on the CONECA - Officers page?

I was going to pop it out of the Mint packaging today to get better photos.

FYI: The new blister packs used in the 2007 mint sets are kind of neat - and display the coins nicely. However - they are a bugger to work with for DV/Error hunting. The center coins are nearly impossible to get to with my microscope - and the plastic tends to distort the view of the coins near the rim (i.e. IGWT on the 1c is difficult to get a clear view of). Today, I'll find out how easy they are to cut open.

[mikediamond]

Great. I'm looking forward to studying it. Send it to my home address. I only visit my P.O. box sporadically. Contact me at mdia1@aol.com and I'll give you my street address.

[mikediamond]

I've come up with a working hypothesis to explain this wierd case of machine doubling. Several years ago some 2001-P half dollars showed up with a rotating collar chip, indicating that the collar itself was rotating. In a large series of half dollars it completed a 360 degree circuit. Perhaps this coin was struck in a loose and rotating collar. That rotation, combined with die jitter, could cause machine doubling on both faces that looks like what we're seeing here.