Mildly interesting spiral pattern on these 1881-A 1 Marks

neildrobertson

I was the winning bidder on an MS66 1881-A 1 Mark at Stack's yesterday. I found it interesting that it has the same spiral pattern as my MS64 1881-A 1 Mark that it is replacing. I'm not positive if I have it on any of my other "A" mintmark 1 Marks of the same type. It must be a by-product of how the planchets were prepared during minting, although I couldn't say with certainty which step.

The MS-66:

The MS-64:

Rexford

Edit: actually, they don’t look like lathe lines. They’re similar to the planchet rings commonly found on ZAR South African coinage, which was also produced on Berlin mint machinery. This characteristic can be found on various types struck with Berlin mint machinery and is a remnant of some part of their planchet production process, though I’m also unsure exactly which step.

bidask

you got that at a good price

neildrobertson

@bidask said:
you got that at a good price

The auction market is starting to have some deals. I won a couple in Stack's past two world auctions. It makes me wonder if 2019 is returning.

Paradisaea

That is a curious pattern and not something I have seen (or noticed) before.

I wonder if the pattern could relate to operation of a knurling machine. My understanding is the raw planchets would have passed through this machine to compress and smooth the edge prior to embossing.

Whether the frictional forces involved in this process were sufficient to mark the planchet is questionable. Yet I can’t think of any other process where the planchet would have been rotated under sufficient force in a manner to produce these semi-concentric rings.

Stunning coin regardless!

Paradisaea

Of possible interest - the 4th edition of Meyers Lexikon (German encyclopedia published 1884-90) provides a general overview of the contemporary minting process and illustrates some of the machines used. Its viewable online both in scanned and text-only formats (which greatly aids online translation): https://www.retrobibliothek.de/retrobib/seite.html?id=111607

davewesen

I think the lines are from the die as I do not see any remnants on the struck coin devices.

neildrobertson

@davewesen said:
I think the lines are from the die as I do not see any remnants on the struck coin devices.

It seems like it is on the 1 here:

davewesen

yep, I can see it on that blow up

coinkat

Could be die polish. This is one reason I like to use a high powered glass and a microscope.

edited to add- look for the raised lines. Imperial German coinage is known for die polish- as is the coinage from the years of the Weimar Republic

neildrobertson

Usually any roughness on the planchet gets obliterated during striking, especially in the fields.