If you have been looking at newer coins for doubled dies you have probably noticed an explosion in the number of hub doubling varieties on US coins since 2022. Some are even of classes that we thought no longer possible in the single-squeeze era (Class II/VI: Example 1 and Example 2)

And I say “hub doubling” there since this explosion is clearly not limited to working dies. I suspect there is a large number of doubled master hubs/dies and working hubs on the 2022-present quarters.

For those two reasons (unexpected and unexplained resurgence of certain classes of doubled dies and an abundance of common doubling likely attributable to earlier in the die making process), there needs to be careful study and consideration for any and all doubling before we can confidently attribute them.

I hope here to publish my current observations so that others can search for more examples to support or rebuke how I would currently attribute this varieties. I can only get my hands on so many coins, and I have not even seen a Denver or San Francisco minted example of some designs, so I am not confident in what to label some of these as.

Do not take any information here to be fact just yet! But please help confirm or rebuke information here where you can.