Definition: The collar is a part of the coin die apparatus that holds the coin planchet in place while the coin is struck. On all coins except the Presidential Dollar coins, the collar applies the edge to the coin during the actual striking, whether the edge is simply plain (like a penny or nickel) or reeded (like a dime or quarter.)
The Presidential Dollars are being struck with a new collar type, which has 3 parts (rather than the one round piece of the regular collar.) The 3-part collar applies the edge lettering to the coins after they have been struck by normal means. The orientation of the edge lettering (whether the heads side is up, or the tails side up) is random, and coins with the tails side up when you read the edge lettering are not errors.
My article on the subject explains much more about the Presidential Dollar coins.
The Presidential Dollars are being struck with a new collar type, which has 3 parts (rather than the one round piece of the regular collar.) The 3-part collar applies the edge lettering to the coins after they have been struck by normal means. The orientation of the edge lettering (whether the heads side is up, or the tails side up) is random, and coins with the tails side up when you read the edge lettering are not errors.
My article on the subject explains much more about the Presidential Dollar coins.
Examples: The collar not only holds the planchet in place during minting, it causes the reeded edge to appear on certain coins, but a special type of 3-part collar adds the edge lettering to the Presidential Dollars.
