(Now that You've added the second image, with the incuse devices versus the raised devices, I am adding to this discussion below on incuse devices, rather than removing this discussion on the raised devices. So my next post below)A doubled die has hub doubling on the die when the die was created. Extreme hub doubling is like the stronger doubled dies:


Note the second hub process added new devices to the die in a rotated fashion. That is called a class one doubled die. The illustration is a drawing to show the differences between a normal devices and
Machine Doubling and a doubled die:
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There are 9 different classes of doubled dies.


So on each class different things can happen during the hub creation purposes. But Class One are the more desirable ones.
Other strong examples of Class One DDO's
Here is a side by side to show the differences the illustrations were showing:

Note normal Liberty Compared with a Machine doubled coin versus a true doubled die. Note the doubling of devices seen on the Bottom image. That is what you are seeing in the drawing a spread between the hub process created on the die. This makes all the coins show that same exact doubling on each coin. The spread most times affects the centers of the devices. A doubled die can have
Machine Doubling:

Note the hub doubling on the full date devices, but the mint mark will show no hub doubling on it. But then note the yellow arrows. They are pointing to where there is
Machine Doubling. So a doubled die can have
Machine Doubling, but
Machine Doubling never creates a doubled die. Why, be cause if doubling is on the die. All the machine that is loose does is to alter the outside/inside edges of the devices. Thus when you see the size of the devices on the previous image, the normal devices are one size. The
Machine Doubling removes the contour of the devices, thus making the devices smaller. But on a doubled die, the spread enlarges the devices.

Thus when you see
Machine Doubling, it is often in a 90 degree angle, removing the contour on that side of the devices. That was the purpose of that illustration that you posted part of.
1. A normal coin is from a normal hub die process.
2.
Machine Doubling alters the devices post strike with a loose machine. (Even doubled dies can be affected by this contour removal)
3. A doubled die comes from a die that has doubling created on the die. The machine does not create a doubled die, it is on the die, thus the term
"Doubled Die.".
Hope this helps?
CoopHome:
I keep find Machine Doubling on coins and think they are doubled dies. What am I missing?