Is there a mint tolerance for doubled die varieties? So somewhere along the way, I heard or read that minor (think class 8/9) doubled die varieties were within mint tolerance for hub doubling. But I can't remember anything about the source for this info. If it is true, it seems these varieties would be worth much less than they are. Yet some designs, like the 2015 Homestead quarter, have over 100 known doubled dies. That is a SUBSTANTIAL percentage of total dies used, which lends support that there is a hub doubling tolerance. Another example is the 2001 cent - there are countless minor DDRs. Apparently the working dies are each inspected in a die shop, but they're obviously not doing a great job of detecting hub doubling unless these minors are acceptable to create. Additionally, Mint workers know there is a clunking sound when hub doubling is produced, so it would be simple to pull these affected dies.
There is collector 'tolerance', but no Mint tolerance when it comes to Doubled Dies, as far as I know. If they spot a doubled die, they would pull it. In almost all cases ('55 DD the exception) the Mint doesn't even know their Dies have been double hubbed.
But how loud is that "clunk"? On minor doubled dies it is probably a pretty minor clunk. And how much ambient noise is there in a machine shop? Enough that I would think they probably wear ear protection. So would they hear that clunk? Probably not.