Microscope - Error pics - SBA Dollar

[mikew148]

I've been looking for errors, on some of my coins, with a new hand held microscope. (Celestron 10x-140x)

 

I'm hoping to get some feedback on a couple of interesting finds.

 

Here's the first one.....1979 P SBA Dollar - in mint set

 

 

 

 

 

LED lighting on this thing is not the best but hopefully you can see the details.

[RWB]

...maybe you should describe what you see in the photos?

[19Lyds]

Obvious machine/die deterioration doubling.

[mikew148]

Ok, in the first photo it appears that this could be a die clash...I compared the second S in STATES to the location of the date from the obverse and it appears a portion of the 9 may have transfered to the reverse .

 

The second looks like doubling in all of In God We Trust - heavy in the D. The bottom portion of the N in IN has been affected as well.

 

I'm not sure what caused the top of the 7 in the date to be damaged/missing. (result of a Clash?)

[halfpint]

 

...to me it appears to be machine/shelf doubling as there is evidence of flatness. imho

[WoodenJefferson]

MikeW well, you do have errors on these Susan B's,

but they are common "ejection or machine doubling"

which occurs during the striking process set off by

something vibrating mechanically during the striking process.

 

In the first image, the "S" in STATES is really a weird

type of doubling as I think you may have two different

processes going on here, mainly machine doubling in

conjunction with a die chip. To me this is more plausible

than a die clash.

 

The second image is a classic example of "machine doubling"

 

The third and final image appears to be PMD (post mint damage)

what leads me to believe this, is the rather shiny surface that has been exposed.

 

Keep looking...

[Crohnos01]

This is a facinating thread, thanks for the post Mike.....

 

For my own edification, how can you tell the difference between a double die strike and the ejection or machine doubling described above? Images in books I have been studying seem like they are the same as the images posted by Mike, but it's probably due to my own untrained eye.....

[physics-fan3.14]

This is a facinating thread, thanks for the post Mike.....

 

For my own edification, how can you tell the difference between a double die strike and the ejection or machine doubling described above? Images in books I have been studying seem like they are the same as the images posted by Mike, but it's probably due to my own untrained eye.....

http://conecaonline.org/content/glossary.html

[WoodenJefferson]

This is a facinating thread, thanks for the post Mike.....

 

For my own edification, how can you tell the difference between a double die strike and the ejection or machine doubling described above? Images in books I have been studying seem like they are the same as the images posted by Mike, but it's probably due to my own untrained eye.....

 

 

True "doubled dies" occur in the hubbing process, or the transfer from working hubs to working dies.

It occurs after the initial squeeze of the die when the working die is removed and heat treated (annealed)

to soften the die steel in order to impart the entire design into the die on the next squeeze. During

subsequent squeezing, a misalignment of the dies nay occur and you end up with a slightly rotated

design from the original design. This "doubled" image is then imparted onto every coin subsequently

struck by this particular die.

 

Note: two distinct serfs (ends of the numbers) this is not just a shift when being struck, this is an actual

second set of impressions on the striking die.

 

 

"ejection, machine doubling" is caused by a vibration transmitted to the dies during the striking process. On the upstroke,

the die will move in no particular direction causing this shelf like or sheared off devices. This is a random occurrence during

the minting process and will not appear on consecutive coins.

 

Note: Since the late 80's the "single squeeze" method has reduced the number of "doubled die" coins because in just one press,

all the design features are imparted.

[Crohnos01]

Thanks for the info on this, but I guess I am still not seeing a huge difference between the 1st photo Mike posted and the doubled date photo you posted... Both seem to have full duplicates of the letters/numbers...Although the "S" doubling in Mikes first photo is by far the most dramatic, it looks like there is subtle doubling of the other letters as well.... or is that the difference? Would there by more symmetrical doubling of the rest of the letters as is shown on the "S" if this were a true double die strike?

[mikew148]

 

 

http://conecaonline.org/content/glossary.html

 

I was looking into buying a book with this information.....Thanks for sharing.

 

 

 

Just one more image of this one to look at......

 

 

This coin came out of the mint ready to star in a horror movie ( all images are of the same coin).....look at that EYE!

 

PS.....It's still in the OGP

[WoodenJefferson]

Obviously, her bun was too tight.