Guess I should just jump in feet first and get used to things...some of what I've seen here disturbs me in a way.
Okay...basics to basics. Machine Doubling (note that I don't call it Damage) is the effect of loose parts in a machine that manufactures hundreds of thousands of coins per day. Many machines making many coins - well into the millions per day, tens of millions per week. Inspections of the pieces coming out of the machine is sparse - a couple of times a day. THUS...millions and millions pass through to bagging without a human eye looking at them to make sure there's nothing wrong with them. Machine doubling can happen on a dozen or a dozen million coins every day. The main point is this....the dies are inspected one for one. The coins are inspected one in a few million.
Now..for the dies. If a die receives doubling from a hub during its creation, the die setter is supposed to notice it. Hundreds of spectacular doubled dies were created over time that never made coins because the die shop did their job - they noted and destroyed the dies before they had a chance to make coins. It's only when the die shop didn't properly do their job did a die make it into manufacturing coins that received its doubled image. Now..we may argue that doubling is doubling, but when the doubling is the result of someone sleeping on the job and not inspecting a piece well enough, and not as simple as a set screw coming loose, there's where I want to be collecting.
Okay...so, machine doubling is 'neat'...sure, I'll give you that. Only thing is, machine doubling is very common. In some years' coins in certain denominations it can be gruesomely common - like 1968S cents...1969S cents. These things are SO common, finding a nicely struck piece without machine doubling is actually a bit of a challenge.
You might say that die life is a million or so coins, so a doubled die is repeated a million times over. In theory this could be possible, but my question is, WHERE ARE THE MILLION DOUBLED DIES?? 1969S cent - fewer than 200 pieces known in any grade. 1970S cent - fewer than 100 pieces known in any grade. 1958 cent - only two pieces known. 1936 DDOs, any of the three main dies - rare in grades above MS65. 1980 DDO cent - fewer than 500 pieces known in any grade. 1983 DDR cents - around 1,500 pieces known, and this is a modern issue...should be a million of them out there! Where are the other 998,500??
The fact is, there are NO known doubled dies in existence for which there are more than 30,000 pieces spoken for, and the king of kings, the 1955 doubled die cent is the most spoken for doubled die on the planet...and it's considered a rarity and goes for king's ransome money! At present we are around the one-thousand mark in cataloging different Lincoln cent doubled dies. In OVER 700 of these cases there are fewer than 100 pieces known to exist, and in at least half of those there are fewer than ten pieces known to exist. WHY?? Well, in part because they are truly rare. In another part because people are skipping over them every day, loupe in hand, and have no clue what they are looking for. Yes, true.
Yes, you have some nice machine doubling there. Some of it is very interesting to look at, and I'm sure very interesting to collect. I give it to you that it's indeed mint created doubling, and in a stretch it would be classified as a mint error...but it's not even in the same class as hub doubled dies. Sorry.
Oh...and as for posting images of doubling...gosh, so many to pick from. My site has over 11,000 images of doubling.
I think I'll pick the one published in all the mags of late - the 1982 DDR, recently discovered in Quincy, Mass, and submitted to me for photos and attribution. I nearly fell out of my chair when this one came in. Meet the 1982 cent doubled die reverse, 1982P-1DR-001. This thing sat dormant for 25 years waiting for someone to discover it, and to date is the only known piece of its kind...even though die life at the time this coin was struck would firmly suggest there are at least 15,000 brothers out there....somewhere.