Machine doubling is also known as ejection doubling.i think its caused in the split second of time just after the coin is struck from it's not coming cleanly out of the die on ejection.In other words,the coin shifts slightly while in the ejection mode just after being struck and,characteristic of machine doubling, a "shelf",is created on some features of the coin.
Whoever is careless with the truth in small matters cannot be trusted with important matters.
You can try this thread as well. I typed out a rather long one that explains the difference between machine doubling and doubled dies. It might help you some.
Mint workers have been quoted as saying that machine doubling is often associated with parts of the press being loose. This seem may be especially associated with the hold-downs.
Comments
Whoever is careless with the truth in small matters cannot be trusted with important matters.
I do get to learn quite a bit here. I'm pretty lucky!
The Lincoln cent store:
http://www.lincolncent.com
My numismatic art work:
http://www.cdaughtrey.com
USAF veteran, 1986-1996 :: support our troops - the American way.
associated with parts of the press being loose. This seem may be especially
associated with the hold-downs.