2003 Wavy Steps Variety

[jtwax]

http://koinpro.tripod.com/Articles/2003CentsWithWavySteps.htm

[coppercoins]

Interesting story - I have one of the mentioned 1994 cents, and have always had a difficult time confidently describing it as a doubled die. What it is, exactly, could fall right in line with Ken's assertion that this could be the effect of the annealing process. It will be interesting to see what follows.

My question would be, if this shows up on a couple of different years of cents because of the annealing process, why doesn't it show on more different years of cents? Secondarily, unless I misunderstand the process, why would there be annealing in the single squeeze method on the first place? I thought the dies were annealed between hubbings to strengthen the metal and soften it for the next hubbing, supposedly unnecessary if there's only one hubbing.

[Robert]

Chuck, your first question is a good one. That makes me think that a change to some other part of the manufacturing process is what's causing this. Perhaps it has something to do with the chrome plating (or other coating processes) on the dies.

Annealing is a softening process, not a strengthening process. Basically you heat the steel die to a certain temperature where the microstructure of the metal is changed. The individual grains within the metal are re-created and/or enlarged, resulting in a softer metal that is easier to work with. You would do this to the blank die just before the first squeeze so that it would pick up the most detail. The hubbing process "work hardens" the die, so in the "multiple squeeze" type of hubbing you'd have to anneal again before the second squeeze. Once your new die had been adequately "squeezed", it would need to be heat treated. This means it will be heated to a different temperature and then cooled in such a manner that the microstructure within the metal has been changed. The result is that the heat treated metal is much stronger/harder/tougher. The tougher die can handle the rigors of coin production much better, without as much die wear, deterioration etc. as an un-heat treated die.