World of Coins

Modern European coins except the euro => Austria and Switzerland => Topic started by: mrbadexample on January 11, 2020, 05:09:44 PM

Title: Austria 10 groschen 1983 partial doubling
Post by: mrbadexample on January 11, 2020, 05:09:44 PM
Hello,

What might have caused this please?  ???
Title: Re: Austria 10 groschen 1983 partial doubling
Post by: Figleaf on January 11, 2020, 10:25:24 PM
Some people call it "die jump", others "echo strike". It happens when the pressure of the strike is set too high. The force of the strike will flow back, causing the die to jump up and make a second strike free of charge.

Peter
Title: Re: Austria 10 groschen 1983 partial doubling
Post by: mrbadexample on January 12, 2020, 01:03:18 AM
Thanks Peter. What I can't reconcile is the partial effect. Surely if the scenario you describe is correct, the whole coin would be affected?  ???
Title: Re: Austria 10 groschen 1983 partial doubling
Post by: Figleaf on January 12, 2020, 09:48:05 AM
This is what a die jump usually looks like. I suppose the force of the strike temporarily deforms either the flan or the die. Take into account that a larger area than you think is affected, but the lines are so close together that they are not obvious.

If the whole coin is double-struck, the error is caused by the flan "sticking" to the upper die for a split second and falling off, rotating slightly before being struck again. This seems to happen in old, slower presses only. Currently, presses strike coins at incredible speed, so the die may come down faster than the coin can fall.

Peter
Title: Re: Austria 10 groschen 1983 partial doubling
Post by: mrbadexample on January 12, 2020, 12:36:14 PM
Perhaps I should have said "...affected to the same degree".

It's the progressive nature of the doubling that I don't understand. If you look at the word REPUBLIK the amount of doubling is greatest on the R, and becomes progressively less until by the time you get to the I it is no longer discernible.

My brain can't fathom how that can happen.  :-[
Title: Re: Austria 10 groschen 1983 partial doubling
Post by: FosseWay on January 12, 2020, 02:22:04 PM
Here is something similar. The doubling is much more obvious at the top (on the tiara and D.G. REG.) than the date. And it seems to be entirely absent on the reverse.