It might just be machine doubling but it might be doubled die. Not sure, still learning. And yea I have read many references and articles and seen many pics of the differences. I know in the back of my mind it's just machine doubling or DDD, but hey, I figured I'd post it anyways to see if I'm wrong or not... just in case
Are all doubled dies as raised as much as the rest of the letters? Cuz it's hard to tell if they are flat or not... so they must be. But looking straight at them they look raised
MD. Check out my thread to see the difference. 1939 Last Coin Purchased For 2019. You can see the difference.
Are all of them that easy to see though? Like those seem to be a couple of the best examples. Are all doubled dies separated like that? I've seen a few articles and there are different types of doubled dies from what I understand, and I cant remember or not if mine is one of those variations or not. But as from what everyone is saying I guess its not
IMHO, it is MD. MD reduces the size of the strike, hub doubling ADDS to the size of the strike. MD is flat, angular and shelf/step like. Hub doubling is fuller, rounder, and not angular and shelflike.
Smart questions. I always say first research and fully understand "how" a doubled die actually happens. Then take a moment to understand the "stages" per your question concerning "types". Visualize how it physically happens then visualize "how" the different stages occur. Once youve done that it is a ton easier to eliminate coins that at first glance you think are doubled dies. This helps so much but still leaves some coins hard to read...and thats where getting the best photos you can for the experts here really help.
Agree with @MatrixMP-9 ...you can find stronger doubling on younger dies and have it diminish and even disappear as the die ages...Spark