Lets talk about my Peace Dollar

No, it doesn't happen, because it is impossible for it to happen.

What does happen however is that people will mistakenly call some lines on a coin die polish lines when they are not die polish lines at all. This occurs because many people do not understand how dies are polished, the don't understand the method used to polish them. And unless you understand that then you cannot understand the very nature of die polish lines.

First of all, picture a die for a dollar. The surface of the die is about 1 1/2 inches across, 38mm. It is basically flat, but there are recesses in the die that form the letters, numbers, and devices. These recesses are a good bit lower than the surface of the die, which forms the fields. So if you took something else that is metal like the die is, and it was flat like the die is, and you pressed those objects together so that they touched face to face all the way across, then it is impossible for the surface of the other metal object to touch any part or the die except the highest parts of the die - the fields. The recesses in the die, the letters, numbers, and devices cannot be touched, at all, by this other metal object. It is impossible and cannot be done. With me so far ?

Now this other metal object I am talking about is a round zinc plate, much like a dinner plate only perfectly flat. That is what is used to polish dies. They have used this method since the early days of the mint. The zinc plate has a hole in the center so it can be attached to a spindle, a machine. The machine spins the zinc plate at a high rate. The surface of the zinc plate is impregnated with diamond dust. The dust comes in varying degrees of fineness, it can be course or very fine, or anywhere in between. It is the zinc plate, along with the diamond dust that does the polishing. And the finer the dust the higher the degree of polish.

Now when a die needs polished the die is attached to a press, kind of like a drill press. The die is locked into a chuck so that it is held perfectly flat and parallel to the surface of the zinc plate. The two are then pressed together with the die being held motionless, the zinc plate spins and polishes the surface, the fields, of the die. It is this spinning and polishing that leaves behind fine lines in the fields of the die. If the diamond dust was course then the lines are course. If the dust was fine then the lines are fine. And it is impossible for the surface of the zinc plate to touch any part of the recesses in the die. So there can be no die polish lines on the letters, numbers, or devices of the die.

Now another part of this is pure mathematics. That being that a round object has a given arc. And the larger the diameter of the object, the larger the arc is. But even an arc can appear to be a straight, or nearly straight, line if the arc is big enough, or if you only observe a small portion of that arc. That is just plain geometry - a fact.

Now on a coin die polish lines appear to be straight, or nearly straight lines. That is because when we see them we are only looking at small portions of the original arc. Remember the coin is only 1 1/2 inches across, pretty small to begin with. And usually the lines we see only cover a small portion of that 1 1/2 inches, so the die polish lines are only a fraction of an inch long.

Now we go back to the plate. The coin die is about 1 1/2 inches across. The plate is say 10 to 12 inches across. The die is held stationary, locked in place, it is not moved around. The plate is held stationary too, locked in place but spinning. And where the die and the plate touch, the die is only touching a small portion of that plate. Visualize an object 1 1/2 inches across held against an object 12 inches across and you begin to get the idea. The larger spinning plate crates fine lines on the surface of the die as it polishes the die. But the portions of the arc of the 12 inch plate are but a fraction of an inch on the die because of the size differential. So when we look at the lines on a finished coin the lines appear to be straight, or very nearly so. The lines are also parallel to each other. And they cannot criss-cross each other because of their very nature, they have to be parallel. The mathematics, the geometry, says so.

Once you have all of this in your mind you have to remember something else. There are other things that can cause or create fine lines in the surface of a die - besides die polishing. Those lines can be created by a worker wiping a rag across the surface of a die to remove dirt or grease. The grit in the dirt or grease, as well as the rag itself, is abrasive and when the rag wipes them off the die, those abrasives can lightly scratch the die. Lines can also be caused/created on a die with small hand tools used by a worker when working on the die.

Both of these types of lines or fine scratches can occur on the fields, or in the devices of the die. And both result in raised lines on the finished coin. But since neither one of them is caused by die polishing, they are not die polish lines. And that is where the mistake comes. People call them die polish lines, when in fact they nothing but die scratch lines. There is a difference, a distinct difference, between die polish lines and die scratch lines on a finished coin.

 

Also, it is important to understand something else. On a finished coin you can have die polish lines and die scratch lines, and lines from harsh cleaning or wiping - all at the same time, on the same coin. This is very common. And that is also part of the reason that people tend to just lump them together and call them all die polish lines, when they are not all die polish lines at all.

One more thing. Any time you scratch a coin, whether it be with a sharp object, by sliding the coin across the surface of a table or counter, or by harsh cleaning, every one of those scratches creates an incuse line in the surface of the coin. But, at the very same time every one of those scratches also causes a raised line on the surface of the coin, right along side the incuse line it caused. This occurs because the metal that is displaced by the scratch has to go someplace. But that metal does not leave the coin, it is instead merely pushed up into a raised line.

All of this combined is what causes the misuse of the term die polish lines.

 

Yes, but it is important to remember that when there are die polish lines, which are raised on a coin, in between each of those die polish lines, and they are very close to each other, there is a low spot between the two high spots. So unless you really look close it can be difficult to distinguish those low spots from incuse lines. And as I said, post strike scratches also create incuse and raised lines on a coin. You can't have one without the other.

However, all you have to do is remember that die polish lines cannot criss-cross, they are always parallel to each other. So if you see a bunch of lines on a coin that are criss-crossing then you know without a doubt that some of those lines are not die polish lines. Whenever lines are criss-crossing some of them will be post strike scratches or die scratches.

And die scratches can be differentiated in the same way. Usually they will be short, and they will not be parallel to the other lines. They also may raised a bit higher than the die polish lines are. Die polish lines are always uniform, die scratches are not.