World of Coins

Modern European coins except the euro => Germany => Topic started by: CameronK on May 06, 2021, 02:41:01 AM

Title: Cologne 1793 8 Heller - Clipped planchet or damage?
Post by: CameronK on May 06, 2021, 02:41:01 AM
Hello!

I'm asking if anyone has seen this type of alteration to this type of coin? Any opinion as to whether it's a clipped planchet from the mint, or damage done later?

Thank you for the review & opinions!
Title: Re: Cologne 1793 8 Heller - Clipped planchet or damage?
Post by: Figleaf on May 06, 2021, 09:58:26 AM
I presume you are referring to the straight edge at 9 o'clock on the upper picture, 3 o'clock at the lower picture.

At the time, a mint would roll fresh copper into plates of the required thickness. This would produce large, long, rectangular copper plates. Flans would be cut from this plate by a machine. The plate would be moved forward in that machine between guides. However, to prevent a small irregularity in the long sides of the plate from stopping the machine, the guides would leave some leeway for the plate to move left or right. To compensate, the knives would be placed to cut inside the plate at all times.

You will understand that the leeway and the position of the knives were calculated on the statistical probability of the variance in the width of the plate. If you are on good terms with numbers, look for more detail here (https://en.wikipedia.org/wiki/Standard_error). Assuming that the guides and knives are set at two standard deviations of the width of the plate, you may expect that the machine will produce correct flans 97.5% of the time. This means that the plate will be too wide and not pass 1.25% of the time and it will produce incomplete flans 1.25% of the time because it is too narrow. The former error will result in a malfunction. The latter would show clearly when the plate is held against the light after cutting. However, the plates are usually heavy and unwieldy.

In such circumstances, some flans may be slightly incomplete, showing the straight edge of the side of the plate, rather than the round shape of the knife, as in your coin. This should not be confused with clipping, which happens outside the mint.

Peter
Title: Re: Cologne 1793 8 Heller - Clipped planchet or damage?
Post by: CameronK on May 07, 2021, 04:36:01 AM
What an education, Fig! Thanks for sharing.