class II and Class VI die doubling

[coinguy47]

Can someone help me understand the difference between these two classes of die doubling? I thought I understood them, but there are those that are look like class VI that are in fact class II. Mr, Wiles just put one on variety vista that is a class II, and I'l be dogged if it doesn't look like a class VI to me. HELP!!!

Tom

[JamesWiles]

Tom: This is an excellent question. Some of the older materials describing the classes of doubled dies confused the two classes. Furthermore they can look similar under certain conditions.

Class II describes the doubling caused by the fact that metal expands when it is heated and contracts when it is cooled. In the multiple hubbing process, the die is removed after its first impression and heated to soften the metal. This heating causes the die to expand. If the die is not cooled properly, the design elements will not have moved back into their initial positions by the time of a second hubbing. Thus the two designs will overlap each other either in a direction toward the center or toward the edge (which direction depends upon whether it is the hub or the die which is in the expanded state). Obviously more dies are expanded than hubs, so more class II doubled dies are listed as toward the center than toward the edge.

Class VI describes the doubling caused by a flattening of the design elements on the hub. Remember that the hub has raised design elements. After multiples of squeezings, the design elements begin to distend. These flattened design elements look extra thick and thus appear to have a doubled image. When a die with this extra thick image comes back from annealing and is ready for its next hubbing, it might not be matched with the old distended hub. With a new hub in place, the designs will not be fully registered, resulting in a doubled image. Class VI then incorporates a couple of different characteristics. First are examples were only extra thickness is seen. Second are those with small splits in the serifs. Third are the combinations of class VI with class II. There are many listings for class II+VI.

I suspect you are referring to the 1957 1c on varietyvista. There are couple of curve balls in the photos. First, it is a LDS specimen. LDS coins show mushy design elements, so the class II has been washed out and thus looks like a class VI. Second, it is a circulated specimen, which also hides the class II separation. So I can readily see how you could think this is a class VI. However, I have seen a high grade MDS, and can assure you that there is a distinct separation toward the center, especially on E PLURIBUS UNUM and the upper wheat edges. I'll work on getting photos of the MDS taken and up, so you can see the difference.

[coinguy47]

James,
Thank you. I was referring to the 1957 1-R-II-C Lincoln on varietyvista. The reason I was asking about it is that I found a 1956 Philly Lincoln that looks exactly like the 1957, and I've been calling it a class VI. Maybe I should send it to you to be sure. It also appears to be a late die state coin and is very nearly uncirculated, but stained. I couldn't find one like it in the CONECA variety master listings, so I though I might send it in to be sure of what it is.

Come to think of it, I have a Kennedy half or two I ought to send as well.

Tom